El Hilo del Clima y el Cambio Climático

[traspotin]

Al hilo de lo que se comentaba sobre enfermedades y su propagación que es favorecida por el calentamiento global

http://sociedad.elpais.com/sociedad/2012/08/23/actualidad/1345740575_484157.html

EE UU se enfrenta al peor brote de virus del Nilo Occidental de su historia
Hasta el momento, han fallecido 41 personas y más de 1.000 han resultado infectadas. La enfermedad se transmite mayoritariamente por la picadura de un mosquito

Estados Unidos se enfrenta al peor brote de virus del Nilo Occidental (VNO) de su historia, según advirtieron ayer las autoridades sanitarias del país. Según los datos facilitados por el Centro de Prevención y Control de Enfermedades (CDC, por sus siglas en inglés), hasta el momento se han registrado 41 muertes y 1.118 personas infectadas, y el número de casos ha crecido de manera drástica (un 60%) en las últimas semanas. El pasado mes de julio tan solo se habían contabilizado 25 casos.

“Desde 1999, año en el que se descubrió el primer caso en EE UU, nunca había habido tantas infecciones -entonces fueron siete los fallecidos y 62 los infectados-. Aún así, aquella cifra es muy lejana a la actual”, ha asegurado vía telefónica Candice Hoffmann, portavoz del CDC.

Cuarenta y siete Estados de los 50 que conforman el país han comunicado casos de infecciones por este virus en personas, pájaros y mosquitos; en 38 de ellos, se han reportado casos en humanos. Hasta el momento, los únicos Estados libres de infección en animales o personas son Hawai, Alaska y Vermont. Generalmente, el virus del Nilo se transmite por la picadura de un mosquito infectado y, en muy contadas ocasiones, por medio de transfusiones de sangre, trasplantes de órganos o la lactancia materna. No se transmite por el contacto casual como tocar o besar a una persona que tenga el virus.

Aproximadamente, el 75% de los casos se están dando en cinco Estados: Luisiana, Dakota del Sur, Misisipi, Oklahoma y Tejas.
La infección por VNO afecta al sistema nervioso. Cerca de una de cada 150 personas infectadas enferma de gravedad. Sus síntomas pueden incluir fiebre alta, dolor de cabeza, rigidez en el cuello, aletargamiento, desorientación, coma, temblores, convulsiones, debilidad muscular, pérdida de la visión, entumecimiento y parálisis. Estos síntomas pueden durar varias semanas y los efectos neurológicos pueden ser permanentes. Cerca del 20% de los casos padece síntomas leves que pueden durar tan solo unos cuantos días y, aproximadamente, el 80% de las personas infectadas por el VNO (cerca de 4 de cada 5) no presenta ninguna clase de síntomas. Del total de 1.118 infectados, a un 56% de los casos se le ha diagnosticado trastornos neuroinvasivos como meningitis o encefalitis.

“Desconocemos exactamente la causa que ha provocado este brote. Puede ser debido a multitud de factores: como que el pasado invierno fuera cálido; las altas temperaturas que llevan sucediendo desde junio o el número de mosquitos y pájaros portadores del virus entre otros. La buena noticia es que nos encontramos en el pico más alto de la infección -marcado a mediados de agosto-, por lo que lo normal es que la incidencia disminuya en las próximas semanas. Aún así, predecimos que se seguirán produciendo casos por lo menos hasta el final de septiembre”, continúa Hoffmann.

Aproximadamente, el 75% de los casos se están dando en cinco Estados: Luisiana, Dakota del Sur, Misisipi, Oklahoma y Tejas. Este último, el más afectado con el 50% de las infecciones, contabiliza más de 600 infectados y por ahora, 21 muertos -11 tan solo en la ciudad de Dallas-. “En Tejas ya se están tomando medidas como regar con pesticidas los campos y educar a las personas en prevención, que es lo que queremos transmitir a la sociedad civil. Además, se les ha hecho un envío de 2,5 millones dólares (casi dos millones de euros) para reforzar las medidas de control”, argumenta Hoffmann.

El CDC recomienda a los ciudadanos que usen cremas repelentes cuando salgan a la calle, que reparen ventanas y puertas para evitar que entren los mosquitos o se vistan con camisas de manga larga o pantalones largos. “Pequeñas cosas que pueden ayudar mucho. Además, no deberían beber agua del grifo en los Estados más afectados”, sostiene Hoffmann. “También se han detectado casos en donantes de sangre, exactamente 242 casos, por lo que en las zonas donde el virus es más virulento estamos recomendando no donar, para así asegurar y proteger nuestros bancos de sangre”, finaliza.

[traspotin]

http://sociedad.elpais.com/sociedad/2012/08/24/actualidad/1345834022_966235.html

Fundido a negro en el Ártico
La extensión del hielo marino en el Polo Norte, en su mínimo
Los científicos auguran que el calentamiento abrirá del todo las aguas en verano en décadas





El Ártico está a punto de batir la mínima extensión del hielo, medida en 2007. Según científicos noruegos y daneses lo ha hecho ya, aunque el instituto de Estados Unidos que lo sigue afirma que aún falta una semana. Poco importa. Nadie duda de que este año se batirá el récord registrado hace cinco veranos, algo que coincide con el patrón previsto por el cambio climático. Los científicos auguran que el océano quedará sin hielo en verano en solo unas décadas, con enormes implicaciones geopolíticas y climáticas: mayor facilidad para transitar rutas marítimas, acceso a nuevos yacimientos de petróleo y gas, disputa por las fronteras... Es como si el libro de geografía cambiase ante nuestros ojos.

Ola M. Johannessen, director del Nansen Environmental and Remote Sensing Center en Noruega, afirmó ayer por teléfono que el área ocupada por el hielo en el Ártico “ya está por debajo del mínimo de 2007”. Johannessen y su grupo utilizan los mismos datos de satélite que el NSIDC de EE UU, considerada la referencia y que ha anunciado que previsiblemente el mínimo se alcanzará la semana que viene. La diferencia está en cómo analizan las imágenes. El Instituto Danés de Meteorología también da ya por bueno el nuevo récord.

Johannessen señala que la superficie helada “nunca ha sido tan pequeña en los últimos siglos”. Desde que en 1979 los satélites comenzaron a medir la extensión del hielo marino, este ha descendido una media del 7,7% cada década.

El anterior récord data del 16 de septiembre de 2007, y es relevante que este año se haya alcanzado —o casi— en agosto, ya que normalmente el hielo ártico sigue fundiéndose hasta principios de septiembre antes de volver a crecer con el frío.

Johannessen no tiene dudas de lo que está pasando. “Es el cambio climático. En 2008 publicamos un estudio en el que correlacionábamos la concentración de CO2 en la atmósfera con la reducción de hielo en el Ártico”. El CO2 procede principalmente de la quema de combustibles fósiles, se acumula en la atmósfera y retiene parte del calor que emite la Tierra. La mayoría de los científicos coincide en que es el principal vector del cambio climático.

Por supuesto que hay variabilidad natural, igual que los años posteriores a 2007 no hubo mínimos, pero sí que hay una tendencia a la diminución.

Carlos Duarte, investigador del Consejo Superior de Investigaciones Científicas que ha liderado expediciones al Ártico, destaca que lo relevante no es solo la reducción de la extensión del hielo, “sino el volumen que ocupa, y cada vez el hielo es más fino”. El núcleo de hielo que resiste el verano es conocido como hielo multianual y puede medir hasta siete metros de espesor. El que se forma y se deshace cada año es mucho menos espeso. Y cada vez hay más de este y menos del primero.

Duarte añade que cada vez hay más variabilidad entre la extensión del hielo de año a año. “Ha habido un cambio de régimen en el Ártico, que puede ser síntoma de un cambio abrupto inminente”.

Al aumentar el deshielo, hay varios factores que aceleran aún más el proceso. El hielo refleja la mayor parte de la luz que llega, pero al fundirse deja paso al agua, que absorbe mucho más calor, que lo que funde más hielo y así sucesivamente. Su situación es completamente distinta de la de la Antártida, un continente helado, con altitudes mucho mayores y mucho menos sensible al calentamiento.

La mayoría de los científicos estima que en unas décadas el Ártico se quedará sin hielo en verano —no en invierno—. Johannessen calcula que eso ocurrirá cuando la concentración de CO2 en la atmósfera alcance las 500 partes por millones (ahora ronda las 400). Al ritmo actual de incremento de unas 2,5 partes por millón al año, faltarían unos 40 años.

Duarte considera que esa es una proyección moderada. “El deshielo del Ártico es un proceso no lineal que se acelera y en el que es muy difícil de predecir. Antes decíamos que se quedaría sin hielo a final de siglo, luego que en 2050 y ahora que puede que en 2030”. Duarte considera que la situación responde a un “cambio climático peligroso”, justo lo que la Convención Marco de Naciones Unidas del Cambio Climático, de 1992, intenta evitar. “Esto es un fracaso de la Convención”, sentencia Duarte.

La reducción del hielo ártico tiene tantas implicaciones como si el Himalaya estuviese bajando de cota. El Ártico es un magnífico territorio inexplorado de gas y petróleo. Hasta ahora, las condiciones para trabajar allí eran demasiado duras y peligrosas, pero poco a poco las petroleras se adentran cada vez más en sus aguas. Ayer, seis activistas de Greenpeace se encaramaron a una plataforma petrolífera de la rusa Gazprom en el Ártico para denunciar el dramático impacto que tendría un vertido. Su argumento es que si BP tardó meses en controlar el escape del golfo de México, pararlo en condiciones extremas y con el riesgo de icebergs sería mucho más difícil.

Todos los países de la región estudian por reclamar su jurisdicción sobre las aguas. Groenlandia, que también siente el calentamiento, augura una carrera por los recursos naturales. Canadá se prepara para controlar el paso del Noroeste, la mítica ruta entre el Pacífico y el Atlántico en la que encalló entre los hielos en 1851 el explorador Robert Mc Clure a bordo del Investigator. Rusia ultima nuevas rutas por el paso del noreste, la misma que en 2009 transitaron dos cargueros alemanes para acortar un 27% el viaje entre Seúl y Rotterdam. Los vecinos ya no ven hielo y frío en el norte, sino un territorio prometedor.

[Currobena]

Un artículo muy interesante sobre los efectos del cambio climático en la capa de hielo del ártico y sus consecuencias para la humanidad:

Why Arctic sea ice shouldn't leave anyone cold   The sea ice is leaving us a bit more every year. It's time to start contemplating its absence, which is why I teamed up with Kevin McKinney to write an extended version of the shorter piece you might see pop up here and there. Because you know, disappearing sea ice isn't without consequences.
And that's why it shouldn't leave you cold.
---
 Why Arctic sea ice shouldn't leave anyone cold  The first world in ancient Norse mythology, Niflheim,
 sounds just like the Arctic ice. Its snow- and ice-melt gave rise to the frost giant Ymir, from whose body the whole cosmos was formed. Today, science tells us a different story about the sea ice, but in that story, too, the ice is far older than humans. According to Polyak et al. (2010):
…sea ice became a feature of the Arctic by 47 [million years before the present], following a pronounced decline [in carbon dioxide concentrations]… Ice was apparently most widespread during the last 2–3 million years, in accordance with Earth's overall cooler climate.
Since modern humans are just 200,000 years old, the ice might as well be eternal.
 But not unchanging. We live in that part of an ice age that is termed an interglacial, when some of the ice retreats in summer. During modern human history the ice cap has melted back each summer as Earth tipped toward the sun, then grown again with new freezing as the year turned toward the Winter solstice.
Polyak et al. continues:
   Nevertheless, episodes of considerably reduced sea ice or even seasonally ice-free conditions occurred... The current reduction in Arctic ice cover started in the late 19th century, consistent with the rapidly warming climate, and became very pronounced over the last three decades. This ice loss appears to be unmatched over at least the last few thousand years…
This information is based upon the detailed study of ‘proxies’—indirect indicators of sea ice extent, including sea-floor sediments containing distinctive mineral, chemical and biological markers; coastal records which include things as diverse as ancient driftwood and geological beach formations; ice-cores from nearby land ice; and tree-ring records, where available.
 Direct observations of sea ice go back a surprisingly long way: a Greek navigator, Pytheas of Massilia, sailed into the open Atlantic in 325 BCE, reaching:
…a land he called "Eschate Thule," where the Sun only set for three hours each day and the water was replaced by a congealed substance "on which one can neither walk nor sail." He was probably describing loose sea ice known today as "growlers", or "bergy bits." His "Thule" was probably Norway…
Since then, humans have repeatedly encountered the ice, from 11^th century Novaya Zemlya, to the Norse colony in Medieval Greenland, to Henry Larsen’s 1944 transit of the Northwest Passage.  For many it proved a fatal encounter; the names of Hugh Willoughby, Willem Barents, Henry Hudson, and John Franklin would only begin a list of Arctic explorers who bartered their lives for their discoveries.  During this time, the annual melt and refreeze of the ice has been relatively consistent.
But that has changed. Since the turn of the millennium, transits of Northwest and Northeast Passages have increased dramatically. In the Northeast, millions of tons of supertanker traffic have passed already, and Russian infrastructure investments indicate that this is a mere beginning. In the Northwest, Arctic charter cruising has become a growing industry. In both, recreational boaters are increasingly common; and many of them now report that they see no pack ice at all.
 Science confirms this anecdotal evidence: satellite measurements show that the ice extent has shrunk since 1979 by nearly 30%. More alarming still, the estimated volume of the sea ice is down a whopping 75%!  When the IPCC released its Fourth Assessment Report in 2007, it was generally thought that the Arctic could become ice-free somewhere near the end of this century. But ice loss has progressed at such speed that scientists now think 2030 might bring the first ice-free Arctic summer. Some say it could even happen this decade.
 And if it does? Well, the Arctic sea ice is a highly efficient reflector of solar energy; where there is no ice, dark ocean water absorbs most of the sunlight. The less ice there is, then, the more the ocean heats up. This in turn melts more ice—an example of a positive feedback in action. It is a feedback chain bearing all kinds of consequences for the Arctic region. Disappearing ice can be good for some species; for instance, tiny algae may profit from the warmer waters and an extended growing season.  But those species dependent upon the sea ice for sustenance or habitat—species from microscopic sea ice diatoms, to seals and walrus, to those charismatic polar bears—may suffer, perhaps even to the point of catastrophe.
 Rapidly changing conditions also have repercussions for human populations, whose income and culture depend on sea ice. Their communities literally melt and wash away with no sea ice to weaken wave action, and their food supplies—often still 50% ‘country food’—are at risk, as populations of traditional prey species (and frequently access to them
as well) are disrupted.
But what happens in the Arctic doesn't stay in the Arctic. When sea ice cover disappears, the changing interaction between sea and atmosphere can shift atmospheric patterns. The results may be felt all over the Northern Hemisphere. As we have seen, a smaller ice pack, combined with an ever earlier melting season, means more and more sunlight is soaked up by dark ocean waters. These warmer waters then release heat and moisture to the atmosphere during fall and winter—an effect already being observed and measured.
 This change in turn may already be disturbing the jet stream, the high-altitude wind that separates southern warm air from cold Polar air. A destabilized jet stream becomes more 'wavy', allowing frigid air to plunge farther south, a possible factor in the extreme winters that were experienced all around the Northern Hemisphere in recent years.
Another side-effect is that as the jet stream waves become larger, they slow down or even stall at times, leading to a significant increase in so-called blocking events. These cause extreme weather simply because they lead to unusually prolonged conditions of one type or another. The recent prolonged heatwave, drought and wildfires in the USA are one example of what can happen; another is the cool, dull and extremely wet first half of summer 2012 in the UK and other parts of Eurasia.
 The accumulation of heat in Arctic waters also influences other frozen parts of the Arctic, such as glaciers and ice caps on Greenland and in the Canadian Archipelago. As there is less and less sea ice to act as a buffer, more energy can go into both melting glaciers from below, and warming the air above them. This has a marked effect on Greenland's marine-terminating glaciers and the Greenland Ice Sheet. Not only are glaciers flowing faster towards sea, but there is also a rapid increase in the summer surface melt Greenland experiences, leading to accelerating mass loss from the Greenland Ice Sheet. As the Arctic warms, an increased contribution to sea level rise is inevitable.
 Another way Arctic warming could have worldwide consequences is through its influence on permafrost. Permanently frozen soils worldwide contain 1400-1700 Gigatons of carbon, about four times more than all the carbon emitted by human activity in modern times. A 2008 study found that a period of abrupt sea-ice loss could lead to rapid soil thaw, as far as 900 miles inland. Apart from widespread damage to infrastructure in northern territories (such as roads, houses and pipelines), the resulting annual carbon emissions could eventually amount to 15-35 percent of today’s yearly emissions from human activities.  This would make the reduction of atmospheric greenhouse gases a much more difficult task.
 An even more worrying potential source of greenhouse gases is the methane in the seabed of the Arctic Ocean, notably off the coast of Siberia. These so-called clathrates contain an estimated 1400 Gigatons of methane, a more potent though shorter-lived greenhouse gas than carbon dioxide. Methane clathrate, a form of water ice that contains a large amount of methane within its crystal structure, remains stable under a combination of high pressure and low temperature.
At a depth of 50 meters or less, the East Siberian Arctic Shelf may contain the shallowest methane clathrate deposits, and thus those most vulnerable to rising water temperatures. High amounts of methane have been recently been measured over ice-free portions of the Arctic Ocean, and the waters of the East Siberian Sea have been shown to be “super-saturated” with methane; large plumes of methane bubbles have been observed there as well. The origins and significance of these emissions are not yet clear, but Arctic methane emissions in general appear to be rising: methane concentrations in the Arctic now average about 1.90 parts per million, the highest in 400,000 years.
 Apart from these unrecoverable sources of fossil fuel, the Arctic is also endowed with large amounts of recoverable oil and natural gas. As the sea ice retreats, the Arctic's fossil treasures are eyed greedily by large corporations and nations bordering the Arctic Ocean. This might lead to geopolitical tensions in a world where energy is rapidly becoming more expensive.  (It is also highly ironic that the most likely cause of the disappearance of Arctic sea ice - the extraction and burning of fossil fuels - could lead to more extraction of said fuels. Another feedback loop.)
News articles on the dangers of Arctic sea ice loss are usually illustrated with pictures of polar bears.  But although many animals in the Arctic are threatened by the vanishing Arctic sea ice, homo sapiens may be the species with most at stake. While Arctic sea ice may be “out of sight, out of mind” for many, it does affect human civilization over the Northern hemisphere, and even beyond:  after thousands of years in which the sea ice played a vital role in the relatively stable conditions under which modern civilization, agriculture and a 7 billion strong world population could develop, it increasingly looks as if warming caused by the emission of greenhouse gases is bringing these stable conditions to an end.
Whether there still is time to save the Arctic sea ice is difficult to tell, but as we've seen, serious consequences will flow from the disappearance of the sea ice.  It appears that these consequences can only be mitigated by keeping fossil fuels in the ground, and carbon out of the air. Whichever way you look at it, business-as-usual is not a sane option.

El blog es muy bueno.   

http://neven1.typepad.com/blog/2012/08/wasislac.html

[pollo]

Un artículo muy interesante sobre los efectos del cambio climático en la capa de hielo del ártico y sus consecuencias para la humanidad:

El blog es muy bueno.   

http://neven1.typepad.com/blog/2012/08/wasislac.html

Me pregunto qué excusas darán cuando los costes de los desastres superen a las ventajas. Vamos de cabeza a la extinción. Cuando empiece a haber problemas con las cosechas o la vida diaria se haga invivible, ¿la gente qué hará?

Todo el mundo se piensa que un fenómeno a escala planetaria no tiene consecuencias. Pagaremos nuestra idiotez, puede que con nuestras vidas..

[traspotin]

Un artículo muy interesante sobre los efectos del cambio climático en la capa de hielo del ártico y sus consecuencias para la humanidad:

El blog es muy bueno.   

http://neven1.typepad.com/blog/2012/08/wasislac.html

Me pregunto qué excusas darán cuando los costes de los desastres superen a las ventajas. Vamos de cabeza a la extinción. Cuando empiece a haber problemas con las cosechas o la vida diaria se haga invivible, ¿la gente qué hará?

Todo el mundo se piensa que un fenómeno a escala planetaria no tiene consecuencias. Pagaremos nuestra idiotez, puede que con nuestras vidas..

Unos más que otros pollo...unos más que otros. Serán los más desfavorecidos los que se lleven el primer y mayor golpe, no en vano cientos de millones de personas viven del deshielo de glaciares que existen en las montañas. Cuando disminuyan o desaparezcan éstos y los ríos no lleven la suficiente agua como para alimentar los cultivos de los que subsisten veremos si aquí todavía seguimos con los mantras: hay ciclos y ciclos (hay sitios y sitios), las temperaturas son las típicas (los pisos nunca bajan) y vamos hacia una era glaciar (si no lo vendo lo alquilo).

@Currobena de ese blog he sacado mucha información del Ártico y estaba preparando otro post con el deshielo récord. Os pongo una de las gráficas que se ve pequeña para que podamos ver la magnitud del cambio que estamos produciendo.



Hay ciclos y ciclos! hora de morir...

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Todavía hay algunos que piensan (y dicen) que la Antártida está ganando hielo, sin embargo la realidad es otra, la Península Antártica es uno de los lugares del globo donde más han subido las temperaturas, lo cual tampoco es decir mucho pues no hay demasiados datos que nos indiquen si son normales o no esos cambios de temperatura (las medidas empezaron en la década de los 50), eso sí, sabemos que los mares del sur se están calentando más rápidamente que los del norte. La masa de hielo está disminuyendo pero para afectar a esa ingente cantidad de hielo hace falta mucha energía y sobre todo tiempo. Todavía hay que desentrañar muchas incógnitas como el efecto del ozono por ejemplo. Pues bien, un grupo de científicos ingleses han obtenido un testigo de hielo de 50.000 años en la Isla de James Ross (el anterior registro era de 400 años). Interpretar los resultados aún es complicado pues el clima en la Antártida es el más extremo del mundo con una gran variabilidad y por lo tanto con mucho ruido, algo a lo que éste testigo debería arrojar algo de luz. Algunos medios se han hecho de la noticia Most Antarctic Peninsula Warming Human-Caused, Antarctic warming part of longer trend y Humans' Role In Antarctic Ice Melt Is Unclear, aunque la temperatura allí, según el núcleo de hielo, no haya sido tan alta desde por lo menos hace 1500 años. Ya saben, hay zonas y zonas.

[traspotin]

Recientemente la Sociedad Americana de Ciencias y la de Meteorología han publicado declaraciones de información que no tienen desperdicio:

http://www.ametsoc.org/policy/2012climatechange.html

Climate Change
An Information Statement of the American Meteorological Society
(Adopted by AMS Council 20 August 2012)

pdf version

The following is an AMS Information Statement intended to provide a trustworthy, objective, and scientifically up-to-date explanation of scientific issues of concern to the public at large.

Background

This statement provides a brief overview of how and why global climate has changed over the past century and will continue to change in the future. It is based on the peer-reviewed scientific literature and is consistent with the vast weight of current scientific understanding as expressed in assessments and reports from the Intergovernmental Panel on Climate Change, the U.S. National Academy of Sciences, and the U.S. Global Change Research Program. Although the statement has been drafted in the context of concerns in the United States, the underlying issues are inherently global in nature.

How is climate changing?

Warming of the climate system now is unequivocal, according to many different kinds of evidence.  Observations show increases in globally averaged air and ocean temperatures, as well as widespread melting of snow and ice and rising globally averaged sea level. Surface temperature data for Earth as a whole, including readings over both land and ocean, show an increase of about 0.8°C (1.4°F) over the period 1901─2010 and about 0.5°C (0.9°F) over the period 1979–2010 (the era for which satellite-based temperature data are routinely available). Due to natural variability, not every year is warmer than the preceding year globally. Nevertheless, all of the 10 warmest years in the global temperature records up to 2011 have occurred since 1997, with 2005 and 2010 being the warmest two years in more than a century of global records. The warming trend is greatest in northern high latitudes and over land. In the U.S., most of the observed warming has occurred in the West and in Alaska; for the nation as a whole, there have been twice as many record daily high temperatures as record daily low temperatures in the first decade of the 21st century.

The effects of this warming are especially evident in the planet’s polar regions. Arctic sea ice extent and volume have been decreasing for the past several decades. Both the Greenland and Antarctic ice sheets have lost significant amounts of ice. Most of the world’s glaciers are in retreat.

Other changes, globally and in the U.S., are also occurring at the same time. The amount of rain falling in very heavy precipitation events (the heaviest 1% of all precipitation events) has increased over the last 50 years throughout the U.S. Freezing levels are rising in elevation, with rain occurring more frequently instead of snow at mid-elevations of western mountains. Spring maximum snowpack is decreasing, snowmelt occurs earlier, and the spring runoff that supplies over two-thirds of western U.S. streamflow is reduced. Evidence for warming is also observed in seasonal changes across many areas, including earlier springs, longer frost-free periods, longer growing seasons, and shifts in natural habitats and in migratory patterns of birds and insects.

Globally averaged sea level has risen by about 17 cm (7 inches) in the 20th century, with the rise accelerating since the early 1990s. Close to half of the sea level rise observed since the 1970s has been caused by water expansion due to increases in ocean temperatures. Sea level is also rising due to melting from continental glaciers and from ice sheets on both Greenland and Antarctica. Locally, sea level changes can depend also on other factors such as slowly rising or falling land, which results in some local sea level changes much larger or smaller than the global average. Even small rises in sea level in coastal zones are expected to lead to potentially severe impacts, especially in small island nations and in other regions that experience storm surges associated with vigorous weather systems.


Why is climate changing?

Climate is always changing. However, many of the observed changes noted above are beyond what can be explained by the natural variability of the climate. It is clear from extensive scientific evidence that the dominant cause of the rapid change in climate of the past half century is human-induced increases in the amount of atmospheric greenhouse gases, including carbon dioxide (CO2), chlorofluorocarbons, methane, and nitrous oxide. The most important of these over the long term is CO2, whose concentration in the atmosphere is rising principally as a result of fossil-fuel combustion and deforestation. While large amounts of CO2 enter and leave the atmosphere through natural processes, these human activities are increasing the total amount in the air and the oceans. Approximately half of the CO2 put into the atmosphere through human activity in the past 250 years has been taken up by the ocean and terrestrial biosphere, with the other half remaining in the atmosphere. Since long-term measurements began in the 1950s, the atmospheric CO2 concentration has been increasing at a rate much faster than at any time in the last 800,000 years. Having been introduced into the atmosphere it will take a thousand years for the majority of the added atmospheric CO2 to be removed by natural processes, and some will remain for thousands of subsequent years.

Water vapor also is an important atmospheric greenhouse gas. Unlike other greenhouse gases, however, the concentration of water vapor depends on atmospheric temperature and is controlled by the global climate system through its hydrological cycle of evaporation-condensation-precipitation.  Water vapor is highly variable in space and time with a short lifetime, because of weather variability. Observations indicate an increase in globally averaged water vapor in the atmosphere in recent decades, at a rate consistent with the response produced by climate models that simulate human-induced increases in greenhouse gases.  This increase in water vapor also strengthens the greenhouse effect, amplifying the impact of human-induced increases in other greenhouse gases. 

Human activity also affects climate through changes in the number and physical properties of tiny solid particles and liquid droplets in the atmosphere, known collectively as atmospheric aerosols. Examples of aerosols include dust, sea salt, and sulfates from air pollution. Aerosols have a variety of climate effects. They absorb and redirect solar energy from the sun and thermal energy emitted by Earth, emit energy themselves, and modify the ability of clouds to reflect sunlight and to produce precipitation. Aerosols can both strengthen and weaken greenhouse warming, depending on their characteristics. Most aerosols originating from human activity act to cool the planet and so partly counteract greenhouse gas warming effects. Aerosols lofted into the stratosphere [between about 13 km (8 miles) and 50 km (30 miles) altitude above the surface] by occasional large sulfur-rich volcanic eruptions can reduce global surface temperature for several years. By contrast, carbon soot from incomplete combustion of fossil fuels warms the planet, so that decreases in soot would reduce warming. Aerosols have lifetimes in the troposphere [at altitudes up to approximately 13 km (8 miles) from the surface in the middle latitudes] on the order of one week, much shorter than that of most greenhouse gases, and their prevalence and properties can vary widely by region.

Land surface changes can also affect the surface exchanges of water and energy with the atmosphere. Humans alter land surface characteristics by carrying out irrigation, removing and introducing forests, changing vegetative land cover through agriculture, and building cities and reservoirs. These changes can have significant effects on local-to-regional climate patterns, which adds up to a small impact on the global energy balance as well.


How can climate change be projected into the future?

Factors that have altered climate throughout history, both human (such as human emission of greenhouse gases) and natural (such as variation of the Sun’s energy emission, the Earth’s orbit about the Sun, and volcanic eruptions), will continue to alter climate in the future. Climate projections for decades into the future are made using complex numerical models of the climate system that account for changes in the flow of energy into and out of the Earth system on time scales much longer than the predictability limit (of about two weeks) for individual weather systems. The difference between weather and climate is critically important in considering predictability. Climate is potentially predictable for much longer time scales than weather for several reasons. One reason is that climate can be meaningfully characterized by seasonal-to-decadal averages and other statistical measures, and the averaged weather is more predictable than individual weather events. A helpful analogy in this regard is that population averages of human mortality are predictable while life spans of individuals are not. A second reason is that climate involves physical systems and processes with long time scales, including the oceans and snow and ice, while weather largely involves atmospheric phenomena (e.g., thunderstorms, intense snow storms) with short time scales. A third reason is that climate can be affected by slowly changing factors such as human-induced changes in the chemical composition of the atmosphere, which alter the natural greenhouse effect.

Climate models simulate the important aspects of climate and climate change based on fundamental physical laws of motion, thermodynamics, and radiative transfer. These models report on how climate would change in response to several specific “scenarios” for future greenhouse gas emission possibilities. Future climate change projections have uncertainties that occur for several reasons — because of differences among models, because long-term predictions of natural variations (e.g., volcanic eruptions and El Niño events) are not possible, and because it is not known exactly how greenhouse gas emissions will evolve in future decades. Future emissions will depend on global social and economic development, and on the extent and impact of activities designed to reduce greenhouse gas and black carbon emissions.

Changes in the means and extremes of temperature and precipitation in response to increasing greenhouse gases can be projected over decades to centuries into the future, even though the timing of individual weather events cannot be predicted on this time scale. Because it would take many years for observations to verify whether a future climate projection is correct, researchers establish confidence in these projections by using historical and paleoclimate evidence and through careful study of observations of the causal chain between energy flow changes and climate-pattern responses. A valuable demonstration of the validity of current climate models is that when they include all known natural and human-induced factors that influence the global atmosphere on a large scale, the models reproduce many important aspects of observed changes of the 20th-century climate, including (1) global, continental, and subcontinental mean and extreme temperatures, (2) Arctic sea ice extent, (3) the latitudinal distribution of precipitation, and (4) extreme precipitation frequency.

Model limitations include inadequate representations of some important processes and details.  For example, a typical climate model does not yet treat fully the complex dynamical, radiative, and microphysical processes involved in the evolution of a cloud or the spatially variable nature of soil moisture, or the atmospheric interactions with the biosphere. Nevertheless, in spite of these limitations, climate models have demonstrated skill in reproducing past climates, and they agree on the broad direction of future climate.


How is the climate expected to change in the future?

Future warming of the climate is inevitable for many years due to the greenhouse gases already added to the atmosphere and the heat that has been taken up by the oceans. Amelioration might be possible through devising and implementing environmentally responsible geoengineering approaches, such as capture and storage measures to remove CO2 from the atmosphere. However, the potential risks of geoengineering may be quite large, and more study of the topic (including other environmental consequences) is needed. The subject of geoengineering is outside the scope of this statement (for more information see AMS Statement on Geoengineering).

In general, many of the climate-system trends observed in recent decades are projected to continue. Those projections, and others in this section,  are largely based on simulations conducted with climate models, and assume that the amount of greenhouse gas in the atmosphere will continue to increase due to human activity. Global efforts to slow greenhouse gas emissions have been unsuccessful so far. However, were future technologies and policies able to achieve a rapid reduction of greenhouse gas emissions — an approach termed “mitigation” — this would greatly lessen future global warming and its impacts.

Confidence in the projections is higher for temperature than for other climate elements such as precipitation, and higher at the global and continental scales than for the regional and local scales. The model projections show that the largest warming will occur in northern polar regions, over land areas, and in the winter season, consistent with observed trends.

In the 21st century, global sea level also will continue to rise although the rise will not be uniform at all locations. With its large mass and high capacity for heat storage, the ocean will continue to slowly warm and thus thermally expand for several centuries. Model simulations project about 27 cm (10 inches) to 71 cm (28 inches) of global sea level rise due to thermal expansion and melting of ice in the 21st century. Moreover, paleoclimatic observations and ice-sheet modeling indicate that melting of the Greenland and the West Antarctic ice sheets will eventually cause global sea level to rise several additional meters by 2500 if warming continues at its present rate beyond the 21st century.

Atmospheric water content will increase globally, consistent with warmer temperatures, and consequently the global hydrological cycle will continue to accelerate. For many areas, model simulations suggest there will be a tendency towards more intense rain and snow events separated by longer periods without precipitation. However, changes in precipitation patterns are expected to differ considerably by region and by season. In some regions, the accelerated hydrological cycle will likely reinforce existing patterns of precipitation, leading to more severe droughts and floods. Further poleward, the greater warming at high latitudes and over land likely will change the large-scale atmospheric circulation, leading to significant regional shifts in precipitation patterns. For example, the model simulations suggest that precipitation will increase in the far northern parts of North America, and decrease in the southwest and south-central United States where more droughts will occur.

Climate-model simulations further project that heavy precipitation events will continue to become more intense and frequent, leading to increased precipitation totals from the strongest storms. This projection has important implications for water-resource management and flood control. The simulations also indicate the likelihood of longer dry spells between precipitation events in the subtropics and lower-middle latitudes, with shorter dry spells projected for higher latitudes where mean precipitation is expected to increase. Continued warming also implies a reduction of winter snow accumulations in favor of rain in many places, and thus a reduced spring snowpack. Rivers now fed by snowmelt will experience earlier spring peaks and reduced warm-season flows. Widespread retreat of mountain glaciers is expected to eventually lead to reduced dry season flows for glacier-fed rivers. Drought is projected to increase over Africa, Europe, and much of the North American continental interior, and particularly the southwest United States. However, natural variations in world ocean conditions at decadal scale, such as those in the North Pacific and North Atlantic basins, could offset or enhance such changes in the next few decades. For the longer term, paleoclimatic observations suggest that droughts lasting decades are possible and that these prolonged droughts could occur with little warning.

Weather patterns will continue to vary from day to day and from season to season, but the frequency of particular patterns and extreme weather and climate events may change as a result of global warming. Model simulations project an increased proportion of global hurricanes that are in the strongest categories, namely 4 and 5 on the Saffir-Simpson scale, although the total counts of hurricanes may not change or may even decrease. Some regional variations in these trends are possible. Simulations also indicate that midlatitude storm tracks will shift poleward. Interannual variations of important large-scale climate conditions (such as El Niño and La Niña) will also continue to occur, but there may be changes in their intensity, frequency, and other characteristics, resulting in different responses by the atmosphere. Heat waves and cold snaps and their associated weather conditions will continue to occur, but proportionately more extreme warm periods and fewer cold periods are expected. Indeed, what many people traditionally consider a cold wave is already changing toward less severe conditions. Frost days (those with minimum temperature below freezing) will be fewer and growing seasons longer. Drier conditions in summer, such as those anticipated for the southern United States and southern Europe, are expected to contribute to more severe episodes of extreme heat. Critical thresholds of daily maximum temperature, above which ecosystems and crop systems (e.g., food crops such as rice, corn, and wheat) suffer increasingly severe damage, are likely to be exceeded more frequently.

The Earth system is highly interconnected and complex, with many processes and feedbacks that only slowly are becoming understood. In particular, the carbon cycle remains a large source of uncertainty for the projection of future climate. It is unclear if the land biosphere and oceans will be able to continue taking up carbon at their current rate into the future. One unknown is whether soil and vegetation will become a global source rather than a sink of carbon as the planet warms. Another unknown is the amount of methane that will be released due to high-latitude warming. There are indications that large regions of the permafrost in parts of Alaska and other northern polar areas are already thawing, with the potential to release massive amounts of carbon into the atmosphere beyond those being directly added by human activity. The portion of the increased CO2 release that is absorbed by the world ocean is making the ocean more acidic, with negative implications for shell- and skeleton-forming organisms and more generally for ocean ecosystems. These processes are only now being quantified by observation and introduced into climate models, and more research is required to fully understand their potential impacts. As impacts of climate change are of regional and local nature, more research is also required to improve climate projections at local and regional scales, and for weather and climate extremes in particular.


Final remarks

There is unequivocal evidence that Earth’s lower atmosphere, ocean, and land surface are warming; sea level is rising; and snow cover, mountain glaciers, and Arctic sea ice are shrinking. The dominant cause of the warming since the 1950s is human activities. This scientific finding is based on a large and persuasive body of research. The observed warming will be irreversible for many years into the future, and even larger temperature increases will occur as greenhouse gases continue to accumulate in the atmosphere. Avoiding this future warming will require a large and rapid reduction in global greenhouse gas emissions. The ongoing warming will increase risks and stresses to human societies, economies, ecosystems, and wildlife through the 21st century and beyond, making it imperative that society respond to a changing climate. To inform decisions on adaptation and mitigation, it is critical that we improve our understanding of the global climate system and our ability to project future climate through continued and improved monitoring and research. This is especially true for smaller (seasonal and regional) scales and weather and climate extremes, and for important hydroclimatic variables such as precipitation and water availability.

Technological, economic, and policy choices in the near future will determine the extent of future impacts of climate change. Science-based decisions are seldom made in a context of absolute certainty. National and international policy discussions should include consideration of the best ways to both adapt to and mitigate climate change. Mitigation will reduce the amount of future climate change and the risk of impacts that are potentially large and dangerous. At the same time, some continued climate change is inevitable, and policy responses should include adaptation to climate change. Prudence dictates extreme care in accounting for our relationship with the only planet known to be capable of sustaining human life.

[This statement is considered in force until August 2017 unless superseded by a new statement issued by the AMS Council before this date.]

NAS tiene un pdf con unas gráficas muy esclarecedoras y un vídeo con las evidencias del calentamiento global:

http://nas-sites.org/americasclimatechoices/files/2012/06/19014_cvtx_R1.pdf

Climate Change: Lines of Evidence

[Republik]

Al final ese fenómeno de Groenlandia, ¿no se da cada siglo y medio más o menos según la paleoclimatología? Yo insisto, las series de los satélites existen desde 1.979 y se nos pueden estar escapando muchas cosas porque puede que estemos dentro de una parte de un ciclo cuya extensión total no se conoce; si la anomalía persiste a lo largo de esta década ya sería para preocuparse y mucho.

[traspotin]

@Republik
Creo que vas a tener que preocuparte mucho más que mucho. El hecho de que un fenómeno puntual pueda ocurrir cada cierto tiempo no significa que no pueda explicarse. El problema es que ahora no es puntual, es global. Se rompen récords de deshielo en todas partes del globo, el nivel del mar sigue subiendo y también su acidez, las temperaturas siguen su camino ascendente y lo seguirán haciendo inevitablemente en el futuro. Hablando de paleoclimatología, insisto, la última vez que tuvimos una temperatura similar (+0.8ºC de anomalía actual), el nivel del mar era unos 6 metros mayor. Lo único que hace falta es el tiempo necesario para derretir el suficiente hielo para que lleguemos a ello. Lo malo es que los políticos de turno pagados por los de siempre hablan de un objetivo de +2ºC, toda una catástrofe climática.

Cuando? No lo sabemos pero todos los cálculos actuales se están quedando pequeños, todo se acelera y lo peor es que el co2 sigue aumentando. Ya se advirtió que el límite seguro estaba en 350 ppm, ya casi vamos por los 400 y quieren parar en 450.

Dentro de un par de décadas, qué excusas pondrán? No lo sé pero seguro que utilizarán la estupidez humana en su beneficio.

Recuerden, los pisos nunca bajan...al igual que las acciones.

[Currobena]

Cómo adaptarse al cambio climático:

This summer, Americans are experiencing climate change as record-breaking heat and drought. Our new normal, with its massive wildfires and severe storms, has given the whole nation a sense of the economic and social consequences of global warming that coastal communities around the world have been experiencing for decades.
If you live near the sea, you're probably witnessing the consequences of too much carbon dioxide in the atmosphere as rising sea level, coastal flooding, and eroding shorelines. In the western Pacific and Indian Oceans, low-lying islands are being engulfed. Meanwhile, in some parts of the Arctic, the rate of erosion has doubled to tens of meters per year due to thawing and the loss of sea, which increases wind fetch. Rising seas also ruin coastal farmland and fresh water aquifers and can destroy biologically rich habitats like marshlands and mangroves.
The costs of either rebuilding or relocating in response are enormous but unavoidable. Furthermore, since the economies of many coastal communities are based on fisheries and tourism, the impacts of anthropogenic climate change threaten their long-term sustainability [1]. Given their vulnerability, coastal communities are on the front line of global warming. But do they have the capacity to adapt to so much environmental change? Do their responses to past challenges suggest strategies for coping with future change? Can we predict which communities are most vulnerable and help them to become more resilient?
To answer these questions, scientists like Tim McClanahan and Joshua Cinner are merging marine and climate change ecology with modern social science. Their goal is to figure out what aspects of coastal communities facilitate social adaptation and how these traits can be promoted. McClanahan is a renowned coral reef ecologist who lives in Kenya and works for the Wildlife Conservation Society. Cinner, a Research Fellow based at James Cook University in Townsville, Australia, is at the forefront of a revolution in the social sciences. He's leading the way to replace the traditional descriptive case study approach with a sort of human macroecology [2], where relationships between societies and their environment are explored by assembling geographic databases of social and ecological traits. This new approach is inherently large scale and statistical as opposed to the traditional local-qualitative method.
McClanahan and Cinner's new book, Adapting to a Changing Environment: Confronting the Consequences of Climate Change, is a primer and also an application of this emerging holistic science. The book is concise, accessible, and written for students, scientists from other disciplines, and policy makers. The authors use coastal east Africa as a case study to develop their model of estimating the “social adaptive capacity” of communities. Unlike temperate and polar coasts, the shorelines of much of the tropics are fringed by coral reefs that buffer coastal communities from waves and storms, provide productive fisheries, and are the base of a tourism economy. The downside is that corals are quite sensitive to ocean warming, and their ongoing global disappearance [3] is both depriving people of their livelihoods and simultaneously increasing erosion as their buffering function is lost [4]. In other words, the vulnerability of this threatened ecosystem is passed on to its human dependents. (Such interconnectedness is a recurrent theme in the book.)
The book contains thorough but understandable introductory chapters on marine fisheries, climate change, and coral reefs. McClanahan and Cinner highlight the challenges of effective fishery management and describe actions taken on international and national levels to more effectively and sustainably manage marine resources. A chapter on coral reef resilience explains what a coral is (a coelentrate, related to jellyfish), how corals form reefs, and the role of the microscopic zooxanthellae that form a crucial symbiosis with their coral hosts. The authors explain how this symbiosis can be disrupted by small temperature increases, leading to the eviction of the zooxanthellae and the “bleaching” and death of the coral if temperatures remain elevated too long. Coral mortality in turn disrupts fisheries as fish habitat is lost and can wipe out tourism based on SCUBA diving. The chapter also includes a refreshingly honest assessment about what local managers can do to make reefs more resilient to climate change (very little [5]).
Coastal communities have a long history of dealing with disturbances such as cyclones. Social adaptive capacity—the ability of a community to respond effectively to change—can be influenced by social traits such as occupational and institutional flexibility, literacy, household assets, infrastructure, and even the degree of social organization. And it's this capacity, and how to measure it, that lies at the heart of the book. Enhancing the adaptive capacity is the ultimate goal and where global nongovernmental organizations like the World Bank are focusing. However, such social engineering is always easier said than done; even with the best of intentions, it often simply creates more poverty, hardship, and dependency [6].
The next step will be testing what is currently a predictive framework; measuring the rate and then the success of adaptive actions by communities and nations and then asking, retrospectively, which characteristics were the best predictors of social adaptive capacity and which responses were most effective. Unfortunately, actually testing the efficacy of policies designed to limit the impacts of climate change on ecosystems and people is rarely done. And even when an approach is found to be ineffective [5], advocates rarely stop promoting it, such as the idea that the implementation of marine protected areas makes reefs more resilient to ocean warming and acidification. Even more challenging is the prospect of identifying which indicators are actually causally linked with adaptive capacity and which merely co-vary with the traits that actually confer resilience.
Having the capacity to adapt is one thing—actually using it is quite another. Here in North Carolina, where our adaptive capacity index would be off the charts in relation to anything in the Indian Ocean, politicians that don't believe in climate change recently introduced legislation that would effectively block coastal counties' attempts at adaptive planning in response to sea level rise. They were lobbied by real estate investment groups who fear that any form of state-sanctioned adaptation would hamper coastal development and depress real estate values. Ironically, the northern shore of North Carolina was just found to be within a global hot spot of sea level rise [7], where sea level is expected to increase by as much as a meter or more this century, whether or not we plan for it.
Of course, the ultimate strategy for adapting to global warming is to rapidly and radically reduce greenhouse gas emissions, i.e., mitigation. The difficulty of this is obvious and has led many scientists and activists to move on to adaptation, which from a distance seems less complex and more likely to actually happen. But the same forces that have blocked mitigation (e.g., denial, short-term economic thinking, etc.) could just as easily trip up adaptive planning.
The African nations where McClanahan and Cinner work emit relatively little carbon dioxide per capita; therefore, mitigation at a global scale is largely beyond reach. For these nations, adaption is the only means to cope with a changing climate. Whether they can build their adaptive capacity quickly enough to meet the challenges ahead remains to be seen. But we'd all do well to start building the adaptive capacity of our own communities, because the front lines of climate change appear to be accelerating.

Es un resumen de un libro publicado recientemente.

http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.1001387

[traspotin]

Nos va a caer la del pulpo.

Death Spiral Watch: Experts Warn ‘Near Ice-Free Arctic In Summer’ In A Decade If Volume Trends Continue
By Joe Romm on Sep 5, 2012 at 7:46 pm
The sharp drop in Arctic sea ice area has been matched by a harder-to-see — but equally sharp — drop in sea ice thickness. The combined result has been a collapse in total sea ice volume.
Many experts now say that if recent volume trends continue we will see virtually ice-free conditions sometime in the next ten years. And that may well usher in a permanent change toward extreme, prolonged weather events “Such As Drought, Flooding, Cold Spells And Heat Waves.”
It will also accelerate global warming in the region, which in turn will likely accelerate both the disintegration of the Greenland ice sheet and the release of the vast amounts of carbon currently locked in the permafrost.



The European Space Agency’s CryoSat-2 probe confirms what the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) at the Polar Science Center has been saying for years: Arctic sea ice volume has been collapsing faster than sea ice area (or extent) because the ice has been getting thinner and thinner.
In fact, the latest satellite CryoSat-2 data shows the rate of loss of Arctic sea ice is “50% higher than most scenarios outlined by polar scientists and suggests that global warming, triggered by rising greenhouse gas emissions, is beginning to have a major impact on the region,” as the UK Guardian reported last month:
If the current annual loss of around 900 cubic kilometres continues, summer ice coverage could disappear in about a decade in the Arctic.
I have focused on sea ice volume for the past 6 years, since I was fortunate enough to hear Dr. Wieslaw Maslowski of the Oceanography Department at the Naval Postgraduate School in a 2006 American Meteorological Society seminar.  He reported that models suggested Arctic ice volume had dropped sharply since the mid 1990s. He then made an alarming forecast:
“If this trend persists for another 10 years–and it has through 2005–we could be ice free in the summer.”
That was in 2006, so he was talking about the possibility of being ice free in 2016.
Looking at volume and thickness helped me avoid the mistake that so many others made in thinking that the sea ice “recovered” after the 2007 minimum in sea ice extent.  The scientific literature and actual observations continued to vindicate Maslowski’s projection.
Since Maslowski’s warning appears to now have been vindicated by the CryoSat-2 data, I asked him for a comment. He said he didn’t want to comment on that data specifically until he’s seen the published results — since there are many inherent uncertainties involved. But he then added:
Regardless of all these uncertainties and for the record, if any of these estimates of arctic sea ice volume decline is close to reality, a near ice-free Arctic in summer can happen not in 2100, 2050 or 2037 but much sooner. One of the main reasons I believe it will happen sooner (i.e. the trend of sea ice volume decline will continue) is that with the shrinking sea ice cover in summer the Arctic Ocean increases its net annual heat content through absorption and redistribution, especially in the upper water column, below the surface mixed layer.
This constitutes a positive feedback to sea ice melt in addition to ice-albedo and other feedbacks, mainly because it can affect the sea ice cover year around, including in winter through upward heat entrainment and reduction of ice growth. The warmer Arctic Ocean can also affect air temperatures and circulation, not only during freeze-up but also in winter and spring. Observational evidence (Jackson et al., 2010 and 2011) suggests increasing sub-surface temperatures and over increasing area in the Canada Basin through 2009, which independently of models supports the argument about the increasing upper ocean heat content.
I do realize that the above sounds ‘alarmist’ and I’ve heard such criticism more than once before but I believe it’s my obligation to make sure that this message is heard by the policymakers and general public.
Maslowski did not make a new timing prediction, but instead directed me to a recent article he was lead author on, “The Future of Arctic Sea Ice,” in Annual Review of Earth and Planetary Sciences.
That article estimated a loss of 1,120 cubic kilometres per year from 1996 to 2007, quite close to the recently reported CryoSat-2 measurements. It continued:
Given the estimated trend and the volume estimate for October–November of 2007 at less than 9,000 km3 (Kwok et al. 2009), one can project that at this rate it would take only 9 more years or until 2016 ± 3 years to reach a nearly ice-free Arctic Ocean in summer. Regardless of high uncertainty associated with such an estimate, it does provide a lower bound of the time range for projections of seasonal sea ice cover.
This is the same estimate Maslowski made in 2006, although he has couched it more conservatively here and has explained that he wouldn’t be surprised if some summer ice lingers above Greenland and Eastern Canada into the 2020s. That’s why he uses the term “nearly ice-free.”
What’s interesting is that the volume trend has in fact continued according to PIOMAS and CryoSat-2. Many other experts are warning that we have effectively passed the point of no return and nearly ice-free are imminent. Fen Montaigne, senior editor of Yale e360, reports:
Peter Wadhams, who heads the Polar Ocean Physics Group at the University of Cambridge and who has been measuring Arctic Ocean ice thickness from British Navy submarines, says that earlier calculations about Arctic sea ice loss have grossly underestimated how rapidly the ice is disappearing. He believes that the Arctic is likely to become ice-free before 2020 and possibly as early as 2015 or 2016 — decades ahead of projections made just a few years ago.
Mark Drinkwater, mission scientist for the European Space Agency’s CryoSat satellite and the agency’s senior advisor on polar regions, said he and his colleagues have been taken aback by the swiftness of Arctic sea ice retreat in the last 5 years. “If this rate of melting [in 2012] is sustained in 2013, we are staring down the barrel and looking at a summer Arctic which is potentially free of sea ice within this decade,” Drinkwater said in an e-mail interview.
Wadhams told the BBC how much warming is accelerated by just replacing the reflective white ice with the more absorptive open ocean:
Prof Wadhams calculates that this increased absorption of the sun’s rays is “the equivalent of about 20 years of additional CO2 being added by man”.
The Cambridge University expert says that the Arctic ice cap is “heading for oblivion.”

O sea que PIOMAS ha sido totalmente ratificado por CRYOSAT2 y de seguir la tendencia actual el Ártico se quedará libre de hielo en esta década. Pero eso no será mucho problema...o sí? El artículo continúa

Not every expert thinks the Arctic will be necessarily be nearly ice free by 2020. And Dr Seymour Laxon who has been working on the CryoSat-2 data said this of the 2020 projection:
Laxon urged caution, saying: “First, this is based on preliminary studies of CryoSat figures, so we should take care before rushing to conclusions. In addition, the current rate of ice volume decline could change.” Nevertheless, experts say computer models indicate rates of ice volume decline are only likely to increase over the next decade.
But whenever the nearly ice free conditions occur (and I’ve long been in the camp that says it’ll be by 2020), those who think we have not effectively crossed a point of no return — those who think we are not in a death spiral — are not paying attention to the thickness and volume analysis. As Yale e360 reported:
Jay Zwally, chief cryospheric scientist at NASA’s Goddard Space Flight Center and an observer of Arctic ice for 40 years, places little stock in the likelihood of a reversal of disappearing Arctic ice. New satellite technology has given scientists the ability to measure the height of sea ice above the water, and hence ice volume. Those measurements, he said, have vividly underscored that Arctic sea ice is in a swoon.
For example, a recent analysis of data from CryoSat and NASA’s ICESat satellite estimates that the volume of sea ice in a large area of the central Arctic Ocean has plummeted in late winter — February and March — by nearly half in just eight years, from an estimated 13,000 cubic kilometers in 2004 to 7,000 cubic kilometers in 2012.
“We’ve gone through a tipping point, and of all the things a tipping point applies to, sea ice is the most appropriate, because the idea is when it goes below a certain thickness it doesn’t go back under present conditions,” said Zwally. “People can get hung up on the specifics and lose track of the big picture, which is that it’s getting worse and it’s going to get [even] worse.”
And that has serious consequences for every person on this planet and countless future generations.
Related Posts:

http://thinkprogress.org/climate/2012/09/05/799761/death-spiral-watch-experts-warn-near-ice-free-arctic-in-summer-in-a-decade-volume-trends-continue/

Pero el Ártico libre de hielo es bueno o malo?

Arctic ice melt 'like adding 20 years of CO2 emissions

The loss of Arctic ice is massively compounding the effects of greenhouse gas emissions, ice scientist Professor Peter Wadhams has told BBC Newsnight.

White ice reflects more sunlight than open water, acting like a parasol.

Melting of white Arctic ice, currently at its lowest level in recent history, is causing more absorption.

Prof Wadhams calculates this absorption of the sun's rays is having an effect "the equivalent of about 20 years of additional CO2 being added by man".


The sea ice extent at 26 August (white) is markedly different from the 1979-2000 average (orange line)
The Cambridge University expert says that the Arctic ice cap is "heading for oblivion".

In 1980, the Arctic ice in summer made up some 2% of the Earth's surface. But since then the ice has roughly halved in area.

"Thirty years ago there was typically about eight million square kilometres of ice left in the Arctic in the summer, and by 2007 that had halved, it had gone down to about four million, and this year it has gone down below that," Prof Wadhams said.

And the volume of ice has dropped, with the ice getting thinner:

"The volume of ice in the summer is only a quarter of what it was 30 years ago and that's really the prelude to this final collapse," Prof Wadhams said.

Parts of the Arctic Ocean are now as warm in summer as the North Sea is in winter, Prof Wadhams said.

Radiation absorbed
The polar ice cap acts as a giant parasol, reflecting sunlight back into the atmosphere in what is known as the albedo effect.

But white ice and snow reflect far more of the sun's energy than the open water that is replacing it as the ice melts.

Instead of being reflected away from the Earth, this energy is absorbed, and contributes to warming:

"Over that 1% of the Earth's surface you are replacing a bright surface which reflects nearly all of the radiation falling on it with a dark surface which absorbs nearly all.

"The difference, the extra radiation that's absorbed is, from our calculations, the equivalent of about 20 years of additional CO2 being added by man," Prof Wadhams said.

If his calculations are correct then that means that over recent decades the melting of the Arctic ice cap has put as much heat into the system as all the CO2 we have generated in that time.

And if the ice continues to decline at the current rate it could play an even bigger role than greenhouse gases.

UK weather effect
Professor Wadhams stresses that there are uncertainties - cloud cover over the Arctic could change and help reflect back some of the sun's radiation.

But then another greenhouse gas - methane, currently trapped in the Arctic permafrost - could be released with warming and make matters worse.

The melting ice could have knock-on effects in the UK. Adam Scaife, from the Met Office Hadley Centre told Newsnight it could help explain this year's miserable wet summer, by altering the course of the jet stream.

"Some studies suggest that there is increased risk of wet, low pressure summers over the UK as the ice melts."

There may be an effect for our winters too: "Winter weather could become more easterly cold and snowy as the ice declines," Mr Scaife said.

Opinions vary on the date of the demise of summer sea ice. The Met Office says it is not expecting the Arctic to be completely ice-free in summer until after 2030.

http://www.bbc.co.uk/news/science-environment-19496674

Baja el albedo por haber menos hielo, el agua atrapa más calor porque el hielo refleja menos radiación solar, lo que provoca que haya menos hielo, lo que provoca...total la energía que atrapa es como si fuera unos 20 años de emisiones de co2.

Y ahora vine lo mejor el deshielo del permafrost provoca la emisión de múcho más metano y co2 atrapado en la vegetación enterrada en la última edad de hielo. Se calcula que hay 1,6 teratoneladas de carbono allí, lo que equivale a lo que hay actualmente en la atmósfera.

Fire and Ice: Permafrost Melt Spews Combustible Methane

Algunos piensan que ya se ha alcanzado el punto de no retorno por lo que será irreversible.

Podéis seguir discutiendo quién tiene la culpa de la burbuja en el hilo de ppcc pero a mí en realidad me preocupan mucho más este tema.

[Currobena]

Una de terruñismo centralista. 

Artículo que muestra como Madrid fue la ciudad donde se empezó a reconocer la influencia humana en el cambio climático por primera vez oficialmente. Aunque el punto de vista del artículo es contrario a dicha tesis, reconoce que el cambio tuvo lugar en la conferencia mundial del clima que tuvo lugar en Madrid en 1995.

Madrid 1995: The Last Day of Climate Science August 7, 2012 by berniel 
  ...
 
 Pushing and Pulling on Human Attribution As the reader may recall from the previous post, the ‘Concluding Summary’ of Chapter 8 that our Dr Al-Sabban is suggesting for use in the Summary for PolicyMakers is conclusively sceptical. This is primarily due to the influence of the entirely sceptical yet-to-be-published Barnett et al paper for which Santer is also a listed author [see here]. Now here we are at this inter-governmental Plenary, which had been called to reach consensus on the wording of a Summary for PolicyMakers in fidelity with the Chapters, and the Chairman is seen working with the Lead Author in a push to over-rule the conclusions of a chapter forged in a drafting and peer-review process by the IPCC’s chosen scientific experts.
The Chairman’s justification for proceeding in this extraordinary manner is based on the emergence of important new evidence. In fact, this ‘new’ evidence, Santer’s ‘vertical’ pattern correlation results, was already available and had been presented to a plenary of chapter authors at their conference in Asheville back in July [see here]. Moreover, these results had been incorporated into the Chapter with the other recent CO2+Sulphate pattern results and altogether given a heightened emphasis in a new introductory ‘Summary.’ But also in Asheville these new results were used in the same way as they would be later used in Madrid, namely, as a vehicle to push through a stronger, more consistent attribution message. In comments already on the table in Asheville, the US Government had recommended just this – a greater emphasis on the contribution of the CO2+Sulphate pattern studies and their use to strengthen a bottom line attribution claim.1  The trouble is that this push was resisted in Asheville and so incompletely realised in the draft arriving for Madrid [9Oct95]. This is why it is necessary to continue the push in Madrid. However, the great stumbling block left unmoved in Ashville now awaits Dr Big Oil, as though a gift for his demonic performance: the unequivocally sceptical ‘Concluding Summary.’
In fact a beachhead of positive attribution had already appeared in the draft of Chapter 8 sent out for review earlier in the year [18Apr95]. This small statement in an earlier introductory ‘Summary’ was surrounded by caveats that seem to cancel it out. Nonetheless it planted a seed of positive attribution:
 <blockquote>A pattern of climate response to human activities is identifiable in observed climate records.</blockquote> After Asheville, the new introduction with the stronger emphasis on the CO2+Sulphate pattern studies delivered a new attribution statement as a ‘bottom line:’
 <blockquote>Taken together, these results point towards a human influence on climate.</blockquote> This is a contraction of the Summary for PolicyMakers bottom line:
 <blockquote>Taken together these results point towards a detectable human influence on global climate.</blockquote> However, despite the ‘taken together’ language, in the context of the entire draft of the Chapter, this is no bottom line. Even within the introductory ‘Summary’ it is preceeded by a strong statement suggesting that estimating ‘natural variability‘—here including external forcing as well as internal variability or ‘noise’—is a difficult problem that remains unresolved. While it trumpets recent major progress, this is only in that model experiments ‘have provided important information about the possible characteristics of the its internal component.’ With such meager progress on the null hypothesis, this is hardly the basis for a positive claim. Why this inconsistency?
The push for positive attribution had always been vigorously challenged within the research community, and Asheville was no exception. There it was met with ‘spirited’ debate, and even after the progress to a bottom line statement, still its retention remained tenuous. At that stage in proceedings it was not only about winning over the room. There was the legacy of the already drafted chapter to deal with. The version of the chapter they were working with was the one sent out to hundreds of scientific experts and government delegates [18Apr95]. In this version, the powerful criticisms emanating from the Barnett et al investigation was not only powerfully re-stated in the conclusion but also fully integrated into every section of the Chapter. Even if every sailor onboard were to agreed, it was almost too late to turn this ship around. But they did not agree. While we know this, and that there were extensive heated debates at Asheville, precious little detail has yet been obtained. One hint to what was going on came when the controversy broke the following spring.
In an early response to criticism for excising the entire Concluding Summary, Santer points out to his fellow authors a ‘supreme irony’ behind ‘the criticism raised by the Global Climate Coalition,’ which is that…
 <blockquote>…I fought very hard at Sigtuna, Brighton, and Asheville to INCLUDE sections on signal and noise uncertainties in Chapter 8. [3Jun96 pdf Santer’s emphasis]</blockquote> Santer is here referring to all three Working Group 1 Lead Author meetings, the first in October 1994, the others in March and July 1995. This ‘supreme irony’ is later revisited by Santer when responding to what he took as a personal attack by Seitz. In his Wall Street Journal op-ed Seitz had mentioned Santer by name as the responsible Lead Author.  In effect, says Santer, I am being ‘taken out’ as a Scientist.” It is ironic that he should be targeted when it was he who…
 <blockquote>…fought hard during all three IPCC Lead Author Drafting Sessions to keep the extended discussion of signal and noise uncertainties within Chapter 8.’ [12Jun96 pdf]</blockquote> Given the North American usage of ‘irony,’ it seems that Santer is claiming that to blame him is precisely contrary to the facts, and so misguided and unfair. It is unfair that he take the rap because it was he who had defended, again and again, the retention of the extraordinarily extended elaborations of the uncertainties in section 8.2 & 8.3 – elaborations that informed and justified the sceptical conclusion. Early removal of these sections (especially before Asheville) would have made it much easier to remove the various sceptical statements in the following discussions of the evidence, and to remove the entire sceptical conclusion. Retaining them, at his own insistence, meant that, after the full success of the push in Madrid, Santer would then be burdened with the excruciating task of recasting all these uncertainties as caveats to a new positive conclusion. And his reward for doing this? He would be singled out. He would be ‘taken out.’ Fate had delivered a severe blow. No wonder he was angry.2
There is an official reason why the post-Asheville version of Chapter 8 sent out to the delegations the required six weeks in advance of Madrid (9Oct95) remained inconsistent with its own introductory Summary on this monumental point of contention. Santer (and Houghton) will tell how his late appointment as Lead Author meant that his Chapter was ‘less mature and polished’ than the rest. But, in less guarded moments we hear of how Santer fought hard at Sigtuna, Brighton, and Asheville. This does not sound like polishing. The inconsistency appears more the legacy of an unresolved battle. There is all the appearance that after Asheville the bottom line attribution statement was decided upon, inserted in the Policymaker’s summary and then hastily installed into the introduction of a Chapter which nonetheless resisted entirely reconfiguring itself to serve this imposter. And it might even have been thanks to Santer himself that positive human attribution arrived in Madrid as but a seed of hope in a field of doubt and uncertainty.
The version of the chapters circulated to the governmental delegations for Madrid was supposed to be final, and yet the inconsistencies within Chapter 8 and between the Chapter and the Summary for PolicyMakers were picked up and highlighted in the solicited and duly submitted USA government comments on the SPM. The USA (and its allies) arrived in Madrid wishing to resolve this inconsistency one way, while the Saudis (and allies) were wanting to retain the over-riding scepticism. For the Saudis to succeed, the weak and ambiguous ‘…points towards…’ in the new introduction could remain (or remain with a slight qualification) while the Concluding Summary would inform the Summary for PolicyMakers now under review. For the USA to succeed, the content of the Chapter would need changes at multiple points, and in every section. Most difficult of all would be to neutralise the scepticism running through the entire conclusion.

 An Unlikely Alliance in the Last Defence of Science So here we are in Madrid on that last morning with Santer presenting the Side Group’s new expanded and strengthened D&A draft. Then Al-Sabban jumps in and suggests that we retreat to the Chapter’s conclusion, which is when Santer loses his cool. Al-Sabban had been specifically invited to the re-drafting group… Why did he not attend?
After an ‘acrimonious exchange,’ Al-Sabban seeks a ruling from the Chair. Houghton moves in firmly behind the Lead Author to give consent for this inter-governmental Plenary to over-ride the assessment process at the Lead Author’s consent. Given the exceptional circumstance of new evidence, it would not be required that the Summary for PolicyMakers is based entirely on the underlying chapters. Also present at the meeting is the founding Chairman of the IPCC, Bert Bolin. A man of immense prestige among all those involved in the IPCC, his consent on this ruling is sought and received. Al-Sabban then issues his protest: ground rules that were previously used to block his suggestions now seem to have changed.
Next, the USA, UK and Canada delegations all move quickly to make it clear that they will not accept the Chapter 8 conclusions. Nor are they willing to retreat to the Summary text prepared for them by the scientists after Asheville. In fact, in the Side Group, the USA, UK and Canada had all been bullish for an even stronger position than the compromise finally agreed. With even that compromise now under threat, they continue this push for stronger wording in the Plenary. Everyone knew when they arrived in Madrid that the stakes were high, and now on this final morning the fight is really on. The Canadians say that the new evidence of the human ‘fingerprint’ is simply ‘stunning.’ The Kenyan delegate, previously in accord with Saudis, had joined the D&A discussion where he was won over to the other side (read Schneider’s heroic tale (pdf)). A momentum sweeps the entire auditorium. The only remaining obstruction is the requirement for consensus and the infuriatingly polite obstinacy of our Dr Mohammad Big Oil.
Well, hang on there! Despite what you might have heard, he was not the only one. It is not widely known that there was another delegate prepared to stand up with Big Oil on this point of order. This is the head of the Australian Delegation, John Zillman.
 The Australian delegate: John Zillman As director of the Australian Bureau of Meteorology since 1978, Zillman, with Bolin and Houghton, had been there in the international negotiations from the beginning. He had been there when the very idea of this politico-scientific contraption had been invented. He had seen the alarmism emerging from the Villach conference (1985), from Hansen (1988) and elsewhere in the late-80s. He had grown concerned both about the integrity of science and the willingness for governments (especially the USA) to trust the scientists when their most extreme views seemed to gain disproportionate attention. He saw the need for both a sober scientific assessment and for government participation, and he believed the IPCC process got it about right. Now, on this last day in Madrid, one wonders if Zillman is the only scientist in the auditorium to notice the rising spectre of a Faustian monster? Houghton’s ruling means that the integrity of the scientific process would be abandoned and its hard-won authority traded so as to expedite a political end – however virtuous that end might be. If there were others also alarmed by the treatment of the Saudi’s objections, then they must be holding their breath, for their voice is not heard.
In the end Australia is prepared to go along with the approval process on the re-draft, but not before two objections have been noted. The first is about preserving the integrity of the science-to-policy process:
 <blockquote>…we were disturbed at the Chairman’s ruling and Dr Santer’s suggestion that the underlying chapter should not be used as the ultimate source of authority on the current state of the science. [AusDelRpt p9]</blockquote> But Australia’s objection is not only in support of IPCC process, it is also in support of the scientific assessment itself: Australia made a stand specifically in support of the science now under threat following this extraordinary procedural ruling.
Australia’s defence of the science in the IPCC assessment had already been aired in the D&A Side Group itself, to which it did send a delegate. (When interviewed in 2012, Zillman does not recall himself participating, but page 7 of the Delegation Report indicates it was him.) Against the push from its Anglophone allies, Australia expressed concerns that…
 <blockquote>…the warming of the last century is still of the same order as (and according to other parts of the report could be smaller than) the level of natural variability evident in the observed record of the last 600 years.3</blockquote> In the Side Group Australia retained concerns about whether it could be said that we had cleared the ‘yardstick’ of natural variability. This takes us back to those same old concerns that have repeated down through the long history of D&A scepticism, back to Wigley in the First Assessment, and all the way back to 1938 when Callendar first served up human attribution for scientific contention [see here]. While the unpublished Barnett et al paper is saying that we have not yet been able to establish what is normal long-term climate variability, Australia at Madrid is saying, where natural variability has been established, it has not been surpassed. What makes this objection difficult to dismiss is that, on the one hand it cannot be passed off as some rogue claim by a governmental delegation, for it is made by deferral to the underlying report. And then on the other hand, the justification given for not taking the underlying chapters as the ‘ultimate source of authority on the current state of the science’ does not help either. Santer’s ‘new evidence’ could do nought to dispel these concerns for the simple reason that it does not even address them.
Australia’s defence of the science in the IPCC assessment is then aired a second time after Santer presents the new D&A draft, after Al-Sabben’s objection and after the Chairman and the various Anglophones delegations move in behind Santer. And it might be asked why it is necessary for Australia to query the wording in the Plenary when the draft was supposed to be consensual of the Side Group participants. The Australian Delegation Report explains that at the end of their final meeting it had been agreed that Santer actually write the new draft – incorporating inter alia their concerns about unsurpassed natural variability. But the next morning, when Zillman reads the draft circulated to the Plenary, the statement on unprecedented warming since 1400 remains as one of the three planks supporting the bottom line human attribution claim.
In his introduction of the text to the Plenary, Santer had explained that he had attempted to respond to Australia’s concerns – but exactly how, it is hard to see. In fact Zillman thinks that Australia’s concerns had been ‘avoided,’ and he says so. In the subsequent discussion Santer himself uses the term ‘sidestepped.’ Note well, dear reader, this little sidestep of the null hypothesis of natural variability, for it was the beginning of something; as we like to say DownUnder From little things big things grow; like a snowball thrown from the height of scientific authority, from this Fuji summit, gathering speed and size, all the way to…Kyoto.4
Australia is not known for standing up for itself and especially not in opposition to the USA when it comes to major defence issues involving geopolitical alliances. Yet, in the context of the UN and other international forums, Australia will often take its own line even when this involves opposition to the USA.5  And here again is Zillman having his little go. While he would never see it that way, others would. And indeed, while the Global Climate Coalition was working hard in support of the Saudis, Greenpeace was also finding various means of persuasion. When Zillman is seen to be siding with the Arabs against the intentions of Australia’s good North America allies, one of the Greenpeace delegates from Australia wonders aloud to Zillman: What do you think the Australian Minister for the Environment might think when he hears about this?
It was at Madrid, and even more so at Rome two weeks later, that the lobbying by the NGOs was stepped up to unprecedented levels, including such veiled threats, and supported by newsletters, flyers and pamphlets. When arriving and departing from the conference centre in Rome, a delegate would pass through a public demonstration, a flyer showing Rome as a wasteland thrust into his hands. If he were unfortunate enough to be identified as sceptical he might even find himself surrounding by a group chanting Climate Criminal!   Witnessing this political circus enveloping these conferences was shocking and disappointing for Zillman. He still shakes his head at the very thought. Challenge him with: But this is politics, isn’t it? and this is where it gets interesting with Zillman.
One might expect that Zillman’s role as the head of the Australian government delegation—not as scientist, not a lead author, but as a government representative—is to represent the policy position of the Australian Government. Perhaps others saw it that way, and undoubtedly in other delegations. But Zillman is adamant that this was never his role, and he would never have accepted it if it were. This might have been the role of the Australian Greenhouse Office, an agency of the Environment Ministry describing itself as ‘the leading Australian Government agency on greenhouse matters.’ And the Greenhouse Office did not shy from encouraging Zillman to a more zealous stance. Brushing aside these advances, Zillman had always held, and held in trust with his Minister, that the role of the Australian delegation is to ensure that the IPCC Assessment remained true to the science. And this cut both ways. He stood by his Minister by always keeping him well-informed of the progress of the assessment and of the negotiations – like when returning to his hotel exhausted at the end of that final night he sat down and wrote out a preliminary report, faxing it off into the Australian afternoon before hitting the pillow. This was just to be sure that the Minister had an accurate account of the drama in case the press started hounding him to comment on some scandalous rumour for an Australian evening news story.

 A Government License to Change the Report That Santer and Houghton saw their role differently to Zillman is illustrated by their deferral to an extraordinary governmental request in defence of their actions. A week before Madrid, Houghton had received the previously mentioned collated comments on the Summary for PolicyMakers from the USA State Department Office of Tim Wirth. For the D&A section of the Executive Summary—which, you will remember, then included the weakly supported bottom line claim that the evidence is pointing towards a detectable human influence—they provide the following comment attributed to the head of the US delegation Robert Watson:
 <blockquote>This text is not fully consistent with the rest of the SPM and various parts of Chapter 8; because this is such a new and important aspect of the report, we believe particular care must be taken. We believe the text here, with some clarification, does represent current understanding as contained in the body of the chapter, but that the executive summary and concluding sections of the chapter may need to be revised. [emphasis added 6]</blockquote> This recommendation to revise Chapter 8 is re-enforced by a statement in the cover letter addressed directly to Houghton. After noting that there are several inconsistencies between the Summary and the chapters, and within chapters, it says that ‘it is essential that the chapters not be finalised prior to the completion of the discussions‘ in Madrid, and that…
 <blockquote>…chapter authors be prevailed upon to modify their text in an appropriate manner following the discussion in Madrid.</blockquote> Thus, just before the conference is about to begin the US State Department indicates that it is not happy with the conclusion of Chapter 8 and tells Houghton that ‘it is essential’ to prevail upon the chapter authors to make changes according to the outcome of ‘the discussion.’ Although not entirely explicit, there remains a strong suggestion that this is a formal request for Houghton to direct Santer to revise Chapter 8, and especially the Concluding Summary. If that is what is being requested, and we take into account the US delegations strategic influence upon the direction of ‘discussions’ in Madrid, then there appears to be a striking similarity between the desired outcome of the US State Department and what in fact occurred. That is, following the completion of ‘the discussions’ in Madrid, this text of the D&A section of the Executive Summary would be revised and expanded as giving the ‘current understanding’ of the Chapter’s science, and the Chapter would be ‘revised’ accordingly.
Make no mistake; this is not about a government caught attempting to abuse a process of diplomacy. This is not about making a scandal of the Watson-Wirth-Gore campaign to win a positive attribution claim in support of the climate treaty talks. We could even find justification for their extraordinary request and partly excuse it. That governmental delegations might persuade in this way is to be expected. In fact, it was expected and it was anticipated in the very design of the IPCC process. The design protected the scientists from giving way to such pressure. What is indicative of Sander and Houghton is not only that they gave way, but that they revealed and promoted this request as a key article in their defence of their actions.
At the height of the controversy Houghton publishes a defence of the chapter changes prominently in Nature under the heading ‘Justification of Chapter 8.’ Beginning with an explanation that the main tasks of Madrid were to accept the chapters and approve the Summary, he then explains ‘acceptance’ thus:
 <blockquote>According to the rules of procedure, ‘acceptance’ means that the meeting is satisfied that they have undergone a thorough process of peer review by experts and by governments and that they present a ‘comprehensive, objective and balanced view’ of the science. 7</blockquote> Houghton then explains how after the peer-review process the chapters had been duly sent out to the delegates prior to the conference. ‘Subsequently, however, many review comments continued to be received.’ Of course, review comments were expected for the Summary but the suggestion is that these were unexpected comments on the chapters. Houghton does not specify how many requests to change the chapters there were [if there were others we would be keen to see them] before gives his single example:
 <blockquote>For instance, the US government, in submitting its points for review, commented on “several inconsistencies” and stated that “it is essential that the chapters not be finalized prior to the completion of the discussion at the IPCC Plenary in Madrid, and that the chapter authors be prevailed upon to modify their text in an appropriate manner following discussion in Madrid”</blockquote> Along with further pressure by delegates and scientists during the meeting, this constitutes Houghton’s justification for the chapter changes. He finishes with an extended affirmation of the IPCC’s procedural and scientific integrity, concluding that ‘despite pressure…’the IPCC has stuck strictly to its brief’ refusing ‘to compromise its science for any political reason…’
Santer is also quoted deferring to this US government request in an earlier Nature news article.7  But its first appearance in the controversy comes in that widely circulated email to ‘all the lead authors of the IPCC Report and all contributors to Chapter 8’ sent on the very day the controversy went public with Seitz op-ed. In this email Santer quotes the request ‘that chapter authors be prevailed upon to modify their text’ in order to ‘underscore the issue of requests received for changes,’ and then he comments:
Clearly, the official view of the United States was that chapters should NOT be finalised prior to Madrid. [12Jun96 pdf ]
What can we make of this? Why draw attention to an attempt by a government to change what is supposed to be a scientific assessment for a very apparent political reason exactly when you are trying to defend that assessment against accusations of political influence? Both Houghton and Santer use this request in defence against the claims by the Merchants of Doubt that Madrid was not supposed to be about the Chapters; in defence against the concerns of Doubters and Deniers that the deadline for comment on the chapters was clearly stated to be prior to Asheville back in July; and in defence against appeals by Seitz and Singer that politics should not be seen to be driving the science. Moreover, we should remember that this defence was being proffered not by some country delegate, but by the Coordinating Lead Author of the Chapter, and then again by the scientist co-ordinating the entire IPCC Scientific Assessment.
In attempting to understand why the United States ‘official view’ might be relevant to Santer’s defence, it is hard to avoid a number of political realities, like the US domination of global politics and that there was a strong lobby keen to exploit the new Clinton Administration’s strident support for global action on climate. It is also hard to avoid the fact that Santer is employed by the US government and that many of the other Lead Authors and Contributors are also dependant on the vastly inflated funding for climatology emanating from the coffers of USA and those countries (UK, Canada) aligned in the push for a positive and consistent attribution claim. Whether or not the view of the USA on chapter alterations was aired from the floor in Madrid (we are yet to see record of this), it is only by resorting to these considerations that we can understand why its official view would be important to Santer’s defence, especially when contrary views were explicitly expressed by the Saudi Arabian and Australian delegations. When Saudi Arabia expressed the very strong view that in this case, as in all cases, the Summary should be based on the underlying chapters, we now know that, for the Chairman, the ground rules had already been changed.
A defence that celebrates what is the essence of the corruption confirms the completeness of that corruption. To the outsider this defence is absurd, like the delusions of some king completely isolated by a court of flatterers. But did anyone try to break that delusion? Was this defence howled down by the scientific establishment? Was there any suggestion that those who occupy the seat of scientific authority might be taking on shades of the enemy? Not likely. Not likely that anyone saw that the snide ad hominem undermining the protests of the devil’s advocate would now ring hollow. No voice in the scientific establishment would stand up to be counted, not with the Saudis, not with Global Climate Coalition, not with the Merchants of Doubt, and not even with the governmental delegate Zillman. Instead, the court flattery would be piled on in spades. Where the political motive was acknowledged there would be praise and support for responding to the political situation in this way. Thereby, the actions of Houghton and Santer in and after Madrid would be vindicated across the scientific establishment as explicitly serving virtuous political interests.8
This is where we find agreement with Zillman’s defence of Madrid—although he would never grant it!—when he pleas that there was no conspiracy. What outraged Seitz and Singer was no shameful secret but the explicit justification of sincere and virtuous actors. And this provides some of the strongest evidence that here we have the tipping point. With all caution abandoned to the task of slaying the apparent enemy, it was this testing moment in this controversy that tipped climate science over into the service of a political cause, and with it went the entire scientific establishment. The message from institutional science became clear. How could there be climate science after Madrid? And sure enough, on this blog and elsewhere, sceptics bear witness to the encouragement and success of those emboldened to sidestep the ancient lore of repeatability, rigorous scepticism and falsification in a pretence to science that demonizes dissent while promoting the more subtle arts of plausible propaganda.

http://enthusiasmscepticismscience.wordpress.com/2012/08/07/madrid-1995-the-last-day-of-climate-science/

[Currobena]

Un efecto dominó de consecuencias incalculables Predicen un deshielo total del Ártico durante el verano de 2016 La capa de hielo del Polo Norte se fundirá completamente entre agosto y septiembre     Periodista Digital, 19 de septiembre de 2012 a las 17:53

       />  Oso polar, Artico, hielo, clima y calentamiento.    />  Oso polar.    />  La masa de hielo afectada por el calor en Groenlandia.    />  La masa de hielo se achica en el Artico.       El hielo del Ártico podría desaparecer durante el verano de 2016 según Peter Wadhams, uno de los principales expertos mundiales en hielo marino.
Ha remitido lo que él mismo califica de «desastre global» al diario británico The Guardian a través de un correo electrónico.
Wadhams avisa en su email de que ya no es suficiente planear qué hacer para luchar contra el cambio climático en las próximas décadas.
Conmina a tomar decisiones urgentes que vayan mucho más allá de la reducción de las emisiones de CO2.
 <blockquote> «Debemos analizar urgentemente otras vías de frenar el calentamiento global, como las soluciones de geoingeniería propuestas hasta la fecha».
 </blockquote> El investigador, responsable del grupo de investigación de física oceánica polar, estudia el grosor de la banquisa ártica con ayuda de los submarinos que atraviesan por debajo.
«Lo he predicho [el colapso del hielo marino durante los meses de verano] durante años. La causa es el calentamiento global: según el clima se ha templado ha habido menos crecimiento del hielo en invierno y más fusión del hielo en verano».
Explica como, debido a este proceso, durante los meses de verano la banquisa entra en un proceso de colapso, que predice se culminará en 2015 o 2016.
Entonces el Polo Norte pasará a estar libre de hielos. Wardhams califica este hecho de «terrible» y avisa de sus riesgos:
 <blockquote> «El agua se calienta, lo que derrite el permafrost, lo que libera ingentes cantidades de metano, un poderoso gas de efecto invernadero».
 </blockquote> Un efecto dominó de consecuencias incalculables.

Para echarse a temblar. Junto con lo de Fukushima, mucho más importante a largo plazo que los pisos de los que hablamos tanto.

http://www.periodistadigital.com/ciencia/medioambiente/2012/09/19/predicen-un-deshielo-total-del-artico-durante-el-verano-de-2016.shtml

[traspotin]

http://www.guardian.co.uk/environment/2012/sep/17/arctic-collapse-sea-ice

Arctic expert predicts final collapse of sea ice within four years
As sea ice shrinks to record lows, Prof Peter Wadhams warns a 'global disaster' is now unfolding in northern latitudes

"As the sea ice retreats in summer the ocean warms up (to 7C in 2011) and this warms the seabed too. The continental shelves of the Arctic are composed of offshore permafrost, frozen sediment left over from the last ice age. As the water warms the permafrost melts and releases huge quantities of trapped methane, a very powerful greenhouse gas so this will give a big boost to global warming."

http://www.science.unsw.edu.au/news/warming-ocean-could-start-big-shift-antarctic-ice

Warming ocean could start big shift of Antarctic ice

“Despite its potential impact, Antarctica's effect on future sea level was not fully included in the last IPCC report because there was insufficient information about the behaviour of the ice sheet. This research changes that. This new, high-resolution modelling approach will be critical to improving future predictions of Antarctica's contribution to sea level over the coming century and beyond.”

http://www.alternet.org/environment/5-diseases-move-north-america-thanks-climate-change?page=0%2C0

5 Diseases on the Move in North America, Thanks to Climate Change

1. The Amoeba That Wants Your Brains
Last year, Naegleria fowleri killed two people in Louisiana who used a neti pot to rinse unfiltered tap water through their sinuses. Unfortunately, the water was also home to this unpleasant organism. In the same year a 9-year-old boy from Virginia died after swimming near a fishing camp and a 16-year-old girl from Florida died after a dip in the St. John’s River. Found all over the world, this amoeba makes its American home among warm freshwater spots in the South—until recently.
2. Oh, Canada: Lyme Disease on the Move
Climate change may be playing out in North America through the rise of Lyme disease in the north. Carried by ticks, the illness is caused by the bacterium Borrelia burgdorferi . Once infected, humans experience fever, headache and other decidedly unpleasant maladies. Most people recover after taking antibiotics, while up to 20% of sufferers experience symptoms that can continue for years.
The Centers for Disease Control reports that in 2010, the most recent data available, there were over 20,000 confirmed cases in North America. Most of the afflicted lived along the Northeast Corridor, while some resided in Wisconsin and Minnesota. Meanwhile, cases are on the rise in Canada.
3. Malaria Marches On
Malaria was largely eliminated in the United States after 1951. However, in 2002, the CDC reported that the number of malaria cases in the U.S. rose sharply through the 1990s, likely due to the rise of international travel. As many as 1,500 cases are now reported annually in the United States. How the warming planet will impact these statistics remains to be seen.
4. Ciguatera Fish Poisoning Comes to America
5. West Nile Virus and You, Together Since 1999
West Nile virus is an " unstoppable" illness, which can leave its victims with symptoms ranging from fever and vomiting to brain-swelling and death. Since 1999, the CDC reports as many as 30,000 people have been infected. As of Aug. 21, 2012, a total of 1,118 West Nile virus cases have been reported in the U.S, including 41 deaths this year alone. According to the CDC , these are the highest numbers of cases per season since West Nile was first detected in the United States.

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