Informe científico internacional: “cambios climáticos abruptos e irreversibles¨

Un informe científico internacional, publicado este jueves, prevé para el mundo un progresivo riesgo de “cambios climáticos abruptos e irreversibles” causados por un calentamiento global más fuerte de lo previsto.

El documento que se extiende por 36 páginas sintetizó más de 1.400 estudios presentados en la conferencia sobre el clima celebrada en marzo en Copenhague; mismo lugar que en diciembre espera recibir a las Naciones Unidas para negociar en dicha reunión un acuerdo que tome el relevo del (próximo a expirar en e 2012), Protocolo de Kyoto.

A seis meses de la conferencia de Copenhague, este informe habla de las previsiones de los expertos en cuanto por ejemplo a: los acontecimientos climáticos extremos; el nivel del mar; el deshielo en el Ártico; la superficie global y la temperatura de los océanos han quedado escasas, y estos se están incrementando significativamente más rápido de lo previsto un par de años atrás, expusieron.

Se plantea entonces en la exposición, que las emisiones de gases con efecto invernadero y otros indicadores climáticos están en o cerca de los límites previstos por el Panel Intergubernamental de la ONU sobre el Cambio Climático (IPCC – informe del 2007),  y que la actividad humana es directa parte responsable en contribuir al calentamiento global.

Ahora no solo estamos ante nuestras acciones directas contra el medio, sino contra las consecuencias mismas de nuestras acciones pasadas; grandiosas cantidades de entre otros, el fuerte gas de efecto invernadero, metano, atrapadas durante milenios en la capa subterránea de hielo del Ártico estarían a punto de ser liberadas a la atmosfera, acelerando significativamente el proceso de calentamiento global.

Tambien se encontraría en peligro la capacidad de los oceanos y bosques de absorber naturalemente el CO2 originado por la quema de combustibles fósiles, según lo indica la investigación..

El nuevo informe fue escrito y revisado por muchos de los científicos que estuvierone n la tarea de recopilación del documento del IPCC; y su proposito es llamar a los politicos a dar pasos necesarios y urgentes:

“Una moderación rápida, sostenida y efectiva… es necesaria para evitar el peligroso cambio climático, sea como sea que está definido”; “Una subida de las temperaturas de más de 2 grados dificultará la vida de las sociedades futuras, y es probable que causen mayores trastornos medioambientales y sociales durante y a partir del próximo siglo”, se advirtieron.

Pero según el IPCC, las naciones industrializadas deberán reducir drástica y significativamente sus emisiones de gas de efecto invernadero; y los números propuestos y necesarios, están entre un 20 y un 45% en comparación con los niveles de 1990. De no ser así será difícil, tal vez imposible, revertir el proceso.

“Objetivos más débiles para 2020, incrementan el riesgo de impactos serios, incluyendo la superación de la barrera a partir de la cual las fuerzas naturales empiezan a empujar las temperaturas hacia arriba incluso más rápidamente”.

Los impactos del cambio climático podrían ser peores de lo previsto, y llegar aun más pronto que tarde; por su parte expertos en clima del Instituto Tecnológico de Massachusetts (MIT), hacen cálculos acerca de la cantidad de grados que la temperatura de la Tierra incrementará para el 2010 y en comparación con lo que se predijo por el 2003: ellos diagnostican que a pesar de los grandes esfuerzos que se han hecho para reducir drásticamente la contaminación, la temperatura de la superficie de la Tierra se incrementará más del doble previsto hacia el 2010, en un total de 5,2 grados.

El primer ministro danés, Lars Loekke Rasmussen, ha insitido a los científicos a dar “indicaciones concretas” a los políticos, cuando el informe sea presentado este jueves durante la Cumbre de la Unión Europea (UE) en Bruselas.

Artículos relacionados:

• Según estudio científico, aves migratorias se mueven cada vez más al norte
• Informe postula la irreversibilidad del cambio climático
• Informe advierte sobre la vulnerabilidad del Caribe Insular frente al cambio climático
• Informe de Greenpeace señala el vínculo entre ganadería y deforestación en la Amazonia

Tags: cambio climáticos abruptos, Informe científico internacional

Un cambio climático desastroso puede llegar sin avisar

Pablo Terramo - Posted on 20 February 2010

(vía NeoFronteras.com)

 

Según un estudio los cambios climáticos dramáticos pueden aparecer súbitamente sin que medie ninguna señal de alarma previa y habiéndose cruzado el punto de retorno. Científicos de la Universidad de California en Davis dicen que es más difícil de lo que se creía predecir cuándo se producirá un rápido cambio en los sistemas naturales de la Tierra. Esto representa una preocupación para los científicos que tratan de identificar los momentos claves del cambio que harán que el clima terrestre cambie súbitamente y se produzca un desastre a nivel global.

El ecólogo Alan Hastings dice que muchos científicos están buscando signos de alarma que anuncien cambios súbitos en los ecosistemas naturales en la esperanza de solucionar el problema o prepararse para él. “Nuestro estudio encuentra, desafortunadamente, que el régimen de cambio con potenciales grandes consecuencias puede ocurrir sin aviso ninguno”, dice. “Esto significa que algunos efectos del cambio climático sobre los ecosistemas sólo se pueden ver una vez que los efectos son dramáticos. El retorno del sistema hacia un estado deseable será difícil, si no imposible”.

El estudio de Hastings y Derin B. Wysham se centra en modelos ecológicos, pero sus hallazgos pueden ser aplicables a otros sistemas complejos, especialmente aquellos relacionados con la dinámica humana, como la explotación de recursos pesqueros o la dinámica de los mercados financieros.

Este investigador es uno de los expertos mundiales en el uso de modelos matemáticos para entender los sistemas naturales. Sus actuales estudios van desde la investigación de la dinámica de las poblaciones de salmón y bacalao al modelado de la respuesta de plantas y animales en respuesta al cambio climático global.

La mayoría de los científicos están de acuerdo en que el cambio climático está causando ya efectos medioambientales, tales como cambios en la frecuencia e intensidad en las precipitaciones, sequías, olas de calor, incendios forestales, aumento del nivel del mar, menor suministro de agua en regiones áridas, mayor cantidad de plagas que afectan los cultivos y bosques o expansión de patógenos tropicales que afectan a humanos hacia otras zonas.

Temen que lo peor esté por llegar. El asesor presidencial John Holdren (no implicado en este estudio) afirmó recientemente que los científicos temen los momentos clave de cambio, umbrales más allá de los cuales un aumento pequeño adicional de la temperatura media u otra variable climática dé como resultado un cambio dramático que afecte al sistema climático. Entre estos puntos clave Holdren lista los siguientes: 

- La desaparición completa de hielo del Océano Ártico en verano, que pueda dar lugar a un cambio profundo en la circulación oceánica y patrones climáticos a lo largo de todo el hemisferio Norte.

- La aceleración en la pérdida de hielo en Groenlandia y la Antártida que conduzca a un cambio en el ritmo de aumento del nivel del mar por encima de 2 metros por siglo.

- La acidificación de los océanos debida a la absorción de dióxido de carbono, que produciría una perturbación masiva en las redes de tróficas oceánicas.  

El resultado es alarmante e invita a la reflexión, sobre todo si nos fijamos en la aplicación de este tipo de modelos a los mercados. La explosión en cadena de las burbujas inmobiliarias a lo largo del mundo y el efecto dominó económico que ha hecho caer una economía tras otra sin previo aviso, nos recuerda a aquellos que con modelos similares predecían que en algún momento eso iba a pasar, aunque no pudieran decir exactamente cuándo. A esos físicos y economistas se les hizo el mismo caso que el que se hace a los actuales climatólogos y ecólogos: casi ninguno.

Al igual que la actual crisis ha sorprendido a muchos, el punto de retorno en el clima mundial también pillará por sorpresa a más de uno, que dirá: “¿ahora?, ¿no iba a ser dentro de un siglo?” 

Fuente: NeoFronteras.com (Copyleft) - imagen de "titoalfredo" en Flickr (cc)
Nota de prensa de UC Davis

BP Oil Spill Stalls Gulf Loop Current

Global Consequences if Current Fails to Reorganize

BP Oil Spill Stalls Gulf Loop Current Update #1, 05-August-2010

YOUR OWN WORD  USA
YOWUSA.COM, 01-August-10
 
Updated 02-August-2010

Marshall Masters

Oceanographic satellite data now shows that the Loop Current in the Gulf of Mexico has stalled as a consequence of the BP oil spill disaster. This according to Dr. Gianluigi Zangari, an Italian theoretical physicist, and major complex and chaotic systems analyst at the Frascati National Laboratories in Italy.

He further notes that the effects of this stall have also begun to spread to the Gulf Stream. This is because the Loop Current is a crucial element of the Gulf Stream itself and why it is commonly referred to as the “main engine” of the Stream.

The concern now, is whether or not natural processes can re-establish the stalled Loop Current. If not, we could begin to see global crop failures as early as 2011.

An Open System in Trouble

The Loop Current is a clockwise flow that extends northward into the Gulf of Mexico and joins the Yucatan Current and the Florida Current to the Gulf Stream.

 

Although at first glance the Loop Current appears confined within the Gulf, scientists define it as an “element of an extremely complex, open system”: as all other “elements” of the so-called “Earth System”, are not separable from the others.
These various “elements” of the Earth System (i.e., atmosphere, landmasses and so forth) are so strongly correlated to one another that at some point, they become indivisible.
Why is this important to all life on the planet? The Gulf Stream is a strong interlinked component of the Earth's global network of ocean conveyor currents, which drive the planet's weather systems.
For this reason, Zangari's concern is that should the Loop Current fail to restart, dire global consequences may ensue as a result of extreme weather changes and many other critical phenomena. The repercussions of which could trigger widespread droughts, floods, crop failures and subsequent global food shortages.
While pundits are certain to trivialize the ramifications of this event, “the real worry” says Zangari, “is that that there is no historical precedent for the sudden replacement of a natural system, with a dysfunctional man-made system. That is, except for the atomic bomb blasts and contamination as a result of nuclear waste and nuclear plant accidents, such as the April 1986, Chernobyl disaster."
In what is now widely regarded by many as “Oil's Chernobyl,” Americans, and particularly Gulf Coast residents are disheartened by a steady stream of bureaucratically bungled responses, which are now proving to be just as a deadly as the initial event itself.
Perhaps even more so, as this toxic brew of incompetence, greed, corruption, oil, Corexit dispersant and other chemicals has unleashed a man-made disaster in the Gulf, with frightful possibilities for the future.

The Corexit Curse

The use of Corexit as a dispersant was first brought to the public's attention during the 1989 Exxon Valdez oil spill.
A powerful solvent used as a dispersant for oil slicks, public knowledge about the dispersant and its long-term effects is hampered by the proprietary protections of its manufacturer, Nalco Holding Company, which is associated with British Petroleum (BP) and Exxon.
What is known, is that this petroleum-based formula is regarded as being at least four times more toxic to life, than the oil is disperses by many environmentalists.
Approximately 1.8 to 2 million gallons of Corexit have been spayed in the Gulf of Mexico. This is a critical fact as current satellite data of the Gulf feeds, tell Zangari that the Loop Current in the Gulf of Mexico has clearly stalled. This due to environmental impacts from a man-made introduction of oil, which were then compounded by other agents (Corexit and so on).
Worse yet, these real-time satellite data feeds offers clear evidence to Zangari that a new artificial system has been generated in the Gulf in a remarkably short period of time. It is this new and unnatural system which has changed the viscosity, temperature and salinity of the Gulf's seawater, thereby causing the Loop Current to stall. A system that has existed for millions of years. 

research facility focused on high-energy physics.
However, what makes Dr. Gianluigi Zangari's findings so vital to the common man, is that for over a decade, he has conducted his continuous global analysis climate research, using publicly available data. Unlike the jealously guarded formulas for Corexit, anyone can vet his research without having to run through a gauntlet of corporate lawyers.

Tracking Zangari's Data

Zangari's assessment is based on daily monitoring of real-time data oceanographic satellite public data feeds called “Real-Time Mesoscale Altimetry” from the Jason, Topex/Poseidon, Geosat, Follow-On, ERS-2 and Envisat satellites.

 

These satellite feeds are captured and made publicly available by NASA, NOAA and by the Colorado Center for Astrodynamics Research (CCAR) at the University of Colorado at Boulder.
These CCAR data maps offer researchers like Zangari a continuous stream of markers for sea and ocean dynamics: surface height, velocity, temperature. A fourth marker that Zangari has found to be especially helpful, are chlorophyll infrared emission maps. This is because they show him real-time changes in the shape of the Gulf Stream. 

In addition to changes in ocean velocity, Zangari is reporting an equally troubling analysis with sea surface temperatures. The data published by Rutgers University is from National Oceanic and Atmospheric Administration (NOAA) data maps. Dr. Zangari re-elaborates and checks these data maps using his own calculus system called SHT (patented in 1999.)
Temperature Comparison - August 2, 2009 / August 2, 2010
(Article Updated on August 2, 2010)

Acknowledgments: Frascati National Laboratories, NOAA and Rutgers University. Analysis by Dr. Gianluigi Zangari (Frascati Labs), July 29, 2010.
Taken altogether, these four oceanographic markers began taking a turn for the worse, shortly after the Deepwater Horizon well explosion on April 20, 2010. This rapid turn of events raised Zangari's concerns about the Gulf's Loop Current, and then on July 28, 2010 the worst case imaginable happened. “The Loop Current 

 

simply stalled,” Zangari noted sadly “and we have no idea if it can reorganize itself, because now we're dealing with troubling unknowns.”

Velocity and Temperature Worries

At present, Admiral Thad Allen is trying to assure Americans that the worst of the disaster has passed and that the oil slicks have disappeared due to natural processes. However the markers from oceanographic satellite feeds Dr. Zangari is studying tell him an entirely different story.

The millions of gallons of Corexit sprayed in the Gulf have given BP and the US government a convenient way to mitigate public concerns by removing the threat from sight. The logic being that since the oil is disappearing, so is the crisis. However, taking oil from the surface and spreading through the water column is not a PR matter. Instead, it has become a convenient way to cover up one massive mistake, with a tragically larger one.

To help understand why, let's assume that what is really happening in the Gulf is not much different from what happens when you shake a bottle of oil and vinegar salad dressing. Leave the bottle on the shelf for a while and the oil and vinegar will naturally separate, each with it's own unique viscosity.

However, when the bottle is shaken the two are mixed. This creates a new, and overall thicker viscosity, hence the dressing pours more slowly. In very simple terms, this is what happened in the Gulf of Mexico, which begs another question. Was the Gulf of Mexico intentionally written off early on, so as to protect the Gulf Stream and America's NATO partners?

Will This Stall Spread Into the Atlantic?

The importance of the Gulf Stream was brought to the forefront in the blockbuster film The Day After Tomorrow (2004) where the Gulf Stream stalled, causing temperatures in New York City to plummet from sweltering to freezing in a matter of hours.

Based on real science, the film showed movie audience how the the Gulf Stream transports warm water from the equatorial regions of the Earth, along American's Eastern seaboard and then across the Atlantic to Northern Europe.

Now, current temperature measurements for the Gulf Stream on the Atlantic Front (from 76 to 47 meridian) now appears to be about 10 degrees Celsius cooler than it was this time last year. Consequently, a direct causality nexus has now been established, between the stall of the Gulf Loop Current and this new temperature drop in the Gulf Stream on the Atlantic Front.

For this reason, the focus of Zangari's research is presently centered on finding signs of a return to the former natural equilibrium of the Gulf. Again, he stresses making predictions (pessimistic or optimistic alike) because “these phenomena are unpredictable because they are ruled by strong non-linearities.”

Nonetheless, we must ponder the question: What does this new nexus portend for our future? To that, Zangari says “we can affirm that this system (the Gulf Stream) is changing in an unpredictable way, which may produce serious consequences on planetary scale.”

BP Oil Spill Stalls Gulf Loop Current Update #1, 05-August-2010 

LA PEQUEÑA EDAD DE HIELO EMPEZARA EN 2010

EL NUEVO SATÉLITE JASON INDICA UN ENFRIAMIENTO GLOBAL DE 23 AÑOS

METEORED.CAMBIO CLIMATICO

Ahora no son sólo las manchas solares la que predicen el enfriamiento global. El nuevo satélite oceanográfico Jason muestra que 2007 fue un “frío” año de La Niña –pero Jason dice que algo más importante está sucediendo: La mucho más grande y persistente Oscilación Decadal del Pacífico (PDO) ha ingresado a su fase fría, diciéndonos que debemos esperar temperaturas moderadamente más frías hasta alrededor de 2030.

Por lo menos durante todo el siglo pasado las temperaturas tuvieron la tendencia de reflejar los calen-tamientos y enfriamientos de 20 a 30 años del centro-norte del Océano Pacífico. No sabemos la cau-sa pero el patrón del último siglo es claro: la Tierra se calentó desde más o menos 1915 hasta 1940, mientras que la PDO también estaba también en una fase cálida (1925 a 1946). La tierra se enfrió luego desde 1940 hasta 1975 mientras que la PDO estaba en una fase fría (1946 a 1977). El fuerte calentamiento desde 1976 hasta 1998 estuvo acompañado de un fuerte y casi constante calenta-miento de la región centro norte del Pacífico. Los anillos de los antiguos árboles de la Baja California y México muestran que deben de haber existido cuando menos 11 cambios de la PDO desde 1650, con un largo promedio de 23 años.

 Todo esto desafía al “consenso” de que el dióxido de carbono emitido por la actividad humana es la responsable de nuestro calentamiento global. Pero la evidencia de un calentamiento causado por el hombre nunca ha sido tan fuerte como lo afirman sus partidarios. El calentamiento de la tierra entre 1915 y 1940 fue tan fuerte como el “aterrante” calentamiento entre 1975 y 1998 tanto en amplitud como en duración –y ocurrió demasiado temprano como para echarle la culpa al CO2 emitido por los humanos- Más recientemente, el clima se ha rehusado de manera porfiada a calentarse desde 1998, aún cuando las emisiones de CO2 de los humanos han seguido aumentando fuertemente.

El satélite Jason es una versión actualizada y más precisa del satélite Poseidon que estuvo vigilando los océanos desde 1992, recogiendo la velocidad de los vientos, la altura de las olas, y cambios en el nivel del mar. Jason está operado por el Laboratorio de Propulsión a Chorro de la NASA y por un equipo francés.

¿Cuántos años de temperaturas mundiales en descenso tendrán que pasar –a fines de una década desde 1998 sin aumentos de temperatura- para romper el “consenso del cambio climático” de Al Gore?.

World's climate could cool first, warm later

• 17:56 04 September 2009 by Fred Pearce, Geneva
• For similar stories, visit the Climate Change Topic Guide 

NewScientist

Forecasts of climate change are about to go seriously out of kilter. One of the world's top climate modellers said Thursday we could be about to enter one or even two decades during which temperatures cool.

"People will say this is global warming disappearing," he told more than 1500 of the world's top climate scientists gathering in Geneva at the UN's World Climate Conference.

"I am not one of the sceptics," insisted Mojib Latif of the Leibniz Institute of Marine Sciences at Kiel University, Germany. "However, we have to ask the nasty questions ourselves or other people will do it."

Few climate scientists go as far as Latif, an author for the Intergovernmental Panel on Climate Change. But more and more agree that the short-term prognosis for climate change is much less certain than once thought.

Nature vs humans

This is bad timing. The UN's World Meteorological Organization called the conference in order to draft a global plan for providing "climate services" to the world: that is, to deliver climate predictions useful to everyone from farmers worried about the next rainy season to doctors trying to predict malaria epidemics and builders of dams, roads and other infrastructure who need to assess the risk of floods and droughts 30 years hence.

But some of the climate scientists gathered in Geneva to discuss how this might be done admitted that, on such timescales, natural variability is at least as important as the long-term climate changes from global warming. "In many ways we know more about what will happen in the 2050s than next year," said Vicky Pope from the UK Met Office.

Cold Atlantic

Latif predicted that in the next few years a natural cooling trend would dominate over warming caused by humans. The cooling would be down to cyclical changes to ocean currents and temperatures in the North Atlantic, a feature known as the North Atlantic Oscillation (NAO).

Breaking with climate-change orthodoxy, he said NAO cycles were probably responsible for some of the strong global warming seen in the past three decades. "But how much? The jury is still out," he told the conference. The NAO is now moving into a colder phase.

Latif said NAO cycles also explained the recent recovery of the Sahel region of Africa from the droughts of the 1970s and 1980s. James Murphy, head of climate prediction at the Met Office, agreed and linked the NAO to Indian monsoons, Atlantic hurricanes and sea ice in the Arctic. "The oceans are key to decadal natural variability," he said.

Another favourite climate nostrum was upturned when Pope warned that the dramatic Arctic ice loss in recent summers was partly a product of natural cycles rather than global warming. Preliminary reports suggest there has been much less melting this year than in 2007 or 2008.

In candid mood, climate scientists avoided blaming nature for their faltering predictions, however. "Model biases are also still a serious problem. We have a long way to go to get them right. They are hurting our forecasts," said Tim Stockdale of the European Centre for Medium-Range Weather Forecasts in Reading, UK.

The world may badly want reliable forecasts of future climate. But such predictions are proving as elusive as the perfect weather forecast.

Read more: Would a cooling world undermine the global warming consensus?

Isla de hielo de cuatro veces el tamaño de Manhattan se desprende de un Glaciar en Groenlandia

Publicado en 07 August 2010. Etiquetas: Cambio Climático, Clima, Groenlandia, Iceberg, Medio Ambinte, Oceanografía

Un informe de un investigador de la Universidad de Delaware afirma que una isla de hielo cuatro veces el tamaño de Manhattan se ha partido desde el Glaciar Petermann en Groenlandia. La última vez que el Ártico perdió un pedazo tan grande de hielo fue en el año 1962.

“En la madrugada del 05 de agosto 2010, una isla de hielo de cuatro veces el tamaño de Manhattan, nació en el norte de Groenlandia”, dijo Andreas Muenchow, profesor asociado de la Universidad de Delaware.
Las imágenes del satélite de esta zona remota a los 81 grados de latitud norte y 61 grados de longitud W, unos 1.000 km al sur del Polo Norte, revela que el Glaciar Petermann perdió alrededor de una cuarta parte de sus 70 kilometros cuadrado flotantes de plataforma de hielo.
Trudy Wohlleben del Servicio Canadiense de Hielo descubrió la isla de hielo en imágenes del satélite de la NASA MODIS-Aqua que tomó los datos el 5 de agosto, a las 8:40 UTC (4:40 GMT), dijo Muenchow. Estos datos se han descargado en bruto, procesados y analizados en la Universidad de Delaware casi en tiempo real como parte de la investigación.
El Glaciar Petermann, el padre de la nueva isla de hielo, es uno de los dos mayores glaciares que quedan en Groenlandia que terminan en las estanterías flotantes. El glaciar se conecta el gran hoja de hielo de Groenlandia directamente con el océano.

La nueva isla de hielo tiene una superficie de al menos 100 kilómetros cuadrados y un grosor de hasta la mitad de la altura del Empire State Building.

“El agua dulce almacenada en esta isla de hielo podría mantener a los ríos Delaware o Hudson ríos fluyendo por más de dos años. También podría mantener toda el agua del grifo público corriente de todo los EE.UU. por 120 días”, dijo el autor.
La isla entrará al Estrecho de Nares, un canal de agua profunda entre el norte de Groenlandia y Canadá.  “El hielo recién nacido de la isla puede convertirse en tierra rápida, bloquear el canal, o romperse en pedazos más pequeños, ya que es impulsado al sur por las corrientes marinas predominantes. A partir de ahí, es probable que siga a lo largo de las costas de la isla de Baffin y Labrador , para llegar al Atlántico en los próximos dos años “.
La última vez que una isla de hielo masiva se formó efue en el año 1962, cuando la plataforma de hielo Ward Hunt “parió” una isla de 230 millas cuadradas. El Glaciar Petermann ha generado islas menores de hielo en el 2001 (34 millas cuadradas) y el 2008 (10 millas cuadradas). En el 2005, la plataforma de hielo Ayles se desintegró y se convirtió en una isla de hielo (34 millas cuadradas) a unas 60 millas al oeste de Petermann Fjord.
Referencia
Greenland glacier calves island 4 times the size of Manhattan, UD scientist reports. http://www.udel.edu/udaily/2011/aug/greenland080610.html

Will Arctic thaw progress?

Arctic. © Flickr.com/lechampiondumonde.com/cc-by-nc

The Voice of Rusia

A record reduction in the area of glaciers in the Arctic Region as a result of the anomalous heat is expected to become clearly visible by the beginning of next month, the Rosgidromet specialists say. Their forecast is based on the fact that the historical thawing speed record was set last month.
The experts with the National Snow and Ice Data Centre in the USA have a similar opinion. They  say that the ice area in the Arctic Region has proved the smallest in the history of satellite observations because the Arctic region was losing 88,000  square  kilometers  of ice area  each day, which exceeds the historical average rate by 1.5 times. True, this month the speed of thawing has dropped somewhat.           
A similar situation was registered in 2007, the Head of the Ice Regime Laboratory at the Arctic and Antarctic Scientific-Research Institute Alexander Yulin says:   
"As observations showed, the smallest ice area, 4.4 million square kilometers in length, was registered in August of 2007. But of interest here is the fact that since 2008 the ice area has been increasing gradually but steadily. There’s a lot of ice in the Laptev Sea and in the East Siberian Sea. Meaning one-year-old thick glaciers. True, the number of glaciers in the Sea of Chukotsk and in the Kara Sea has quickly decreased. The thinnest glaciers have thawed in the two Arctic seas."    
Of course, the thawing of glaciers in the Arctic Region affects the condition of the World Ocean. Among the negative consequences specialists mention a quick rise of the water level. This may trigger the flooding of the coastal areas and islands, destroy many eco-systems and lead to the extinction of many species of animals and fishes. And still, for the time being, there’re no grounds for catastrophic scenarios concerning the so-called global warming, Alexander Yulin says:   
"If we take a one-century-long period, we’re now at the very peak of warming, which has caused a whole series of warm years. In the coming decade a period of relative cool is highly probable."    
We should not forget that human activity has a lot to do with the current climate change. If we don’t take care of the Earth, a catastrophic scenario, presented by the supporters of the global warming, becomes a possibility. They say that by the middle of this century the polar hat will thaw completely in summer.
“However, our forecast is more moderate: a cold snap will come in the 30s, and the Arctic ice will not go anywhere. And as regards the current record heat, which is registered on the greater part of Europe, it neither offers proof of nor disproves the theory of global warming,” Alexander Yulin says.
To confirm or disprove this hypothesis, you should observe the weather change within 30 years. We’re keeping track of the ice situation because ice is a good indicator of climate change,” the Russian scientist stressed.

Severe Arctic thaw predicted for this summer: U.S. institute

Thicker, multi-year ice in much of the Arctic Ocean is being replaced by weaker first-year ice, scientists say. (PHOTO BY JANE GEORGE) 

"The old, thick ice... is now beginning to melt out"

SPECIAL TO NUNATSIAQ NEWS

 

RANDY BOSWELL
Postmedia News

Arctic sea ice remains headed for another severe thaw this summer, tracking close to 2007’s record-setting retreat as some of the polar region’s oldest and thickest slabs — driven south into the warmer waters of the Beaufort Sea — are “beginning to melt out,” according to the latest report from the U.S. National Snow and Ice Data Center.

The Colorado-based institute, which bases its analysis on a 31-year satellite record of Arctic ice cover, said in its Aug. 4 report that this summer’s retreat is unlikely to surpass the unprecedented September 2007 meltdown to 4.13 million square kilometres — which alarmed scientists and governments around the world — but is trending toward another severe thaw expected to reach 5.0 million square kilometres or less.

“It would take a very unusual set of conditions in August to create a new record low,” the NSIDC stated in its report.

But echoing warnings issued recently by other U.S. and Canadian scientists that shrinking ice volume in the Arctic has become as much of a concern as declining ice area, the institute highlighted the ongoing replacement of thicker, multi-year ice in much of the Arctic Ocean by weaker first-year ice.

“Back in the 1970s and 1980s, old ice drifting into the Beaufort Sea would generally survive the summer melt season,” the centre stated. “However, the old, thick ice that moved into this region is now beginning to melt out, which could further deplete the Arctic’s remaining store of old, thick ice.”

There were also signs, however, that this year’s ice melt slowed in July compared with the rate of retreat recorded in May and June. Both of those months saw the ice melt faster than in any previous May or June since satellite measurements began in 1979.

But in July, the rate of retreat was closer to the annual average.

Still, this summer’s sea-ice minimum — expected to be reached around Sept. 15, before the annual winter re-growth begins — is on track to be one of the two or three smallest since 1979.

Reductions of sea ice have businesses and governments throughout the circumpolar world preparing for increased ship traffic and economic activity in Arctic waters.

But scientists are generally concerned about the relatively rapid melting in recent years because the Arctic ice is believed to be approaching a “tipping point” that could see ice-free summers in the region in the coming years, with significant impacts on Arctic wildlife and global climate systems.

 

The world's melting glaciers

Glaciers around the world are retreating at unprecedented rates as temperatures rise due to climate change. Some ice caps, glaciers, sea ice and even an ice shelf have disappeared altogether in this century and many more are retreating so rapidly that they may vanish within a matter of decades.

 guardian.co.uk, Tuesday 28 April 2009 17.05 BST 

Antarctica. A polar landscape of snowy hills, dramatic cumulus clouds and coastal glaciers. A glacier is a large, slow-moving mass of ice formed from compacted layers of snow, that slowly deforms and flows in response to gravity and high pressure. Glaciers cover vast areas of the polar regions and are found in mountain ranges of every continent except Australia

 

Biggest ice island for 48 years breaks off Greenland glacier

An ice island 100 square miles in area has broken off Petermann Glacier in Greenland, and is thought to be the biggest formation of its kind for 48 years. Photograph: AP

Scientists say the 100 square mile ice island, 600ft thick, is 'very unusual' and the biggest formation of its kind since 1962

Damien Pearse 
The Guardian, Saturday 7 August 2010 
Article history

An ice island with an area of 100 square miles has broken off from one of Greenland's two main glaciers in what scientists say is the biggest such event in the Arctic in nearly 50 years.

The huge chunk of ice, which is 600ft thick, broke off the Petermann Glacier, located about 620 miles south of the North Pole, on Thursday.

It is now drifting in a remote area called the Nares Strait between Greenland and Canada.

Andreas Muenchow, professor of ocean science and engineering at the University of Delaware, said satellite images have revealed that the glacier has lost about a quarter of its 43-mile-long floating ice shelf.

The last time such a large ice island formed was in 1962 when the Canadian Ward Hunt Ice Shelf calved an island. Smaller pieces of that chunk became lodged between real islands inside the Nares Strait.

Muenchow said he had expected an ice chunk to break off from Petermann, one of the two largest remaining glaciers in Greenland, because it had been growing in size for seven or eight years. But he said he did not expect it to be so large.

"The freshwater stored in this ice island could keep the Delaware or Hudson Rivers flowing for more than two years," said Muenchow, whose research in the area is supported by the National Science Foundation.

"It could also keep all US public tap water flowing for 120 days."

He said it was hard to judge whether the event occurred due to global warming because records on the sea water around the glacier have only been kept since 2003.

"Nobody can claim this was caused by global warming. On the other hand nobody can claim that it wasn't," Muenchow said, adding that the flow of sea water below the glaciers is one of the main causes of ice calvings off Greenland.

Regine Hock, a glacial geophysicist at the University of Alaska Fairbanks, told the National Geographic that the breakup of ice shelves is "a normal process that happens all the time".

But she said that such a "huge, huge piece of ice … is very unusual".

Scientists have said the first six months of 2010 were the hottest globally on record. The El Niño weather pattern has contributed to higher temperatures, but many scientists say elevated levels of man-made greenhouse gases are pushing temperatures higher.

The initial discovery of the breakaway island was made by Trudy Wohlleben of the Canadian Ice Service.

Experts believe the island could fuse to land, break up into smaller pieces, or slowly move south where it could block shipping.

Petermann Glacier spawned smaller ice islands in 2001 (34 square miles) and 2008 (10 square miles).

El albedo de la tierra disminuye

NASA

En promedio, el sol ilumina la tierra y deja 341 vatios por metro cuadrado de energía. El sol emite más energía sobre nuestro planeta cada hora que las aplicaciones de la humanidad en un año entero. Esta energía proporciona es el combustible necesario para soportar la mayoría de las formas de vida de nuestro mundo y lo mantiene lo bastante caliente como para sostenerla. La luz del sol también proporciona la energía al sistema climático de la tierra.

La imagen superior muestra el albedo medio de la tierra para marzo de 2005, medido por el instrumento CERES (Clouds and Earth’s Radiant Energy System) del satélite Terra de la NASA. El albedo es la fracción de la luz del sol entrante que nuestro planeta refleja de nuevo a espacio. Si la tierra fuera cubierta por hielo como una bola gigante de nieve, su albedo sería cerca de 0.84, o sea que reflejaría la mayoría (el 84 por ciento) de la luz del sol que incide sobre ella. Por otra parte, si la tierra estuviera cubierta totalmente por un manto de bosque verde oscuro, su albedo estaría cerca de 0.14, que significa que la mayoría de la luz del sol sería absorbida y nuestro mundo sería más cálido que lo es hoy. Las medidas basadas en los satélites estimaron a finales de los años 70 que el albedo medio de la tierra era del orden de 0.30.

En la imagen de albedo de arriba, el blanco muestra áreas donde la tierra reflejó el porcentaje más alto de la radiación solar de onda corta. Áreas en azul marino muestran las zonas donde la tierra reflejó el porcentaje más bajo de la radiación solar de onda corta.

Nótese cómo los valores más altos de albedo están en las regiones donde la tierra está cubierta sobre todo por la nieve y el hielo, o nubes, o ambas cosas. Los valores más bajos del albedo ocurren en las áreas cubiertas de bosque, océanos y mares.

Hay factores en el sistema climático de la tierra que influyen en cuánta luz del sol es reflejada por nuestro mundo de nuevo al espacio, y cuánto toma y almacena en forma de calor. Cualquier cambio significativo en el brillo de la superficie de la tierra o en el grado de nubes y de aerosoles en la atmósfera afecta a cuánto la tierra refleja la luz del sol, que, a la vez, afecta al sistema climático.

Una caída de tan poco como un 0.01 en el albedo de la tierra tendrían una mayor influencia en el clima como el efecto de doblar la cantidad de dióxido de carbono en la atmósfera, que haría que la tierra conservara 3.4 vatios adicionales de energía por cada metro cuadrado de área superficial.

En de mayo el 6 de 2005, en la revista Science, el equipo de ciencia CERES divulgó que el albedo de la onda corta de la tierra ha estado declinando constantemente como ha puesto de manifiesto el instrumento CERES del satélite Terra, desde que comenzó a tomar medidas en febrero de 2000.

Sobre el periodo de cuatro años (2000 al 2004), el instrumento CERES midió una disminución del albedo de 0.0015, que iguala a la mitad adicional de vatio de energía por el metro cuadrado que conservó en el sistema de la tierra. El equipo de CERES no está seguro sobre qué causó esta disminución en el albedo.

El equipo se centrará en el fututo en comparar datos del CERES con los datos de otros sensores espaciales para considerar si hay algunos cambios significativos en el sistema del clima de la tierra durante ese tiempo que podría explicar el cambio en el albedo.
Imagen de la NASA por Jesse Allen, Earth Observatory Team, usando datos del CERES Science Team Langley Research Center de la NASA.
Más información en:
http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=16905

Cambios estacionales en el albedo superficial de la tierra

Cambios de albedo estacionales. Foto NASA. Ver texto para detalles.

Accionado por los cambios estacionales de la luz del sol disponible, cerca de los 50 millones de kilómetros cuadrados de la superficie de la tierra experimentan una transición de zona helada a deshelada cada año. La nieve y el hielo desaparecen y, de nuevo, la tierra se congela y endurece, la vegetación verde aparece y se descolora. Los ciclos se repiten año tras año.

Los sensores basados en los satélites pueden detectar muchos de estos procesos a través de los cambios estacionales en la cantidad de la luz del sol reflejada por la superficie de la tierra en varias longitudes de onda. El porcentaje de la luz que una superficie refleja respecto de la luz total que incide sobre ella es el albedo de la superficie. Las superficies brillantes, con poder reflectante, tales como nieve fresca, tienen un alto albedo. Las superficies oscuras, absorbentes, tales como bosques densos, tienen un albedo bajo.

Estas imágenes de parte del globo terrestre exhiben el excedente estacional de las observaciones del albedo de Asia tomadas por el Multi-angle Imaging SpectroRadiometer (MISR) de la NASA en el 2004. Las imágenes de la columna de la izquierda están en color natural, o sea, imágenes hechas de manera similar a lo que verían nuestros ojos. Las de la columna derecha muestran el albedo pero solamente en las longitudes de onda de la luz que las plantas utilizan para la fotosíntesis o el albedo para la radiación fotosintético activa (Photosynthetically Active Radiation, PAR). Los lugares en donde la superficie están reflejando la mayoría de las longitudes de onda fotosintéticas (alto albedo) están con tonalidades grisáceas o tántalo, los lugares en donde la superficie están absorbiendo la mayoría de las longitudes de onda fotosintéticas (albedo bajo) son coloreados desde un verde oscuro a negro. Las áreas grises indican la carencia de datos, por ejemplo, debido a nubosidad persistente. Las partículas en la atmósfera pueden interferir con la toma de medidas del albedo superficial porque las partículas dispersan luz del sol entrante en todas las direcciones; sin embargo, todos los efectos de la dispersión de la atmósfera se han quitado de estas imágenes del albedo.

Entre diciembre y febrero, la nieve cubre las latitudes norteñas, haciendo que la superficie de la tierra más reflexiva y, por lo tanto, aumentando el albedo. El albedo en longitudes de ondas fotosintéticas activas es también alto (blanco, tántalo y los valores amarillos) porque es invierno, y las plantas no son muy activas. Mientras que progresan las estaciones, el albedo en longitudes de onda fotosintética activas de la luz disminuye porque las plantas son abundantes y activas; para el período de junio-agosto, la vegetación en Asia está absorbiendo casi toda la luz fotosintética que viene del sol con albedos. Áreas con los albedos más altos uniformes durante la estación de crecimiento del verano incluye la meseta tibetana semiárida (centrada groseramente en los globos), la península árabe (lejos izquierda), y el ártico (arriba).

Para más detalle y globos adicionales, visite la página de la imagen de MISR MISR image page.
Imagen cortesía de NASA/GSFC/LaRC/JPL, MISR Team. Texto de John Martonchik (JPL) y Clare Averill (Raytheon ITSS/JPL).

Todo el texto fue tomado de:
http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=16900

Este año ha dado comienzo una 'mini era de hielo' que bajará la temperatural global

TERRA. Noticias

 

Víctor Manuel Velasco Herrera, investigador del Instituto de Geofísica de la Universidad Nacional Autónoma de México (UNAM), ha pronosticado que debido a una reducción de la intensidad solar va a dar comienzo un periodo glacial que podría extenderse entre 60 y 80 años.

La disminución de la temperatura global es todo un hecho según un comunicado de la Universidad Nacional Autónoma de México (UNAM). La temperatura global bajará de 0,2 grados a un grado centígrado, suscitando importantes cambios en los territorios según sus emplazamientos, además, supondrá diversas consecuencias de gran calado. Esta glaciación está vinculada a la disminución de la incidencia del sol, a los calentamientos globales y a los lapsos de enfriamiento terrestre.
Victor Manuel Velasco Herrera, experto en materia geofísica, ha explicado que el Sol es el factor más importante que contribuye a los calentamientos y enfriamientos que experimenta el planeta. Ha expuesto que después de registrar una década de temperaturas máximas entre los años 80 y 90 y de atravesar un periodo de transición desde 2005, hemos pasado a una mini edad de hielo. “Todas las heladas históricas que están ocurriendo en el mundo son muestra de ello”, ha puntualizado el investigador.
Velasco Herrera ha indicado, además, que esta glaciación no va a equilibrar el calentamiento global que estamos viviendo y que, si las predicciones se cumplen, durante el periodo glacial vamos a sufrir severas sequías e inundaciones. Por este motivo ha aconsejado que, si no queremos lamentar pérdidas económicas y humanas, debemos  adaptar rápidamente nuestras infraestructuras nacionales y estar preparados para las nuevas condiciones climáticas que nos deparan.

 

Thermohaline Experiment

climateprection.net

In Climate science

Details about the experiment follow. This sub-experiment is being led by Nick Faull (climate science) and Tolu Aina (computing).

The experiment is not a prediction of the likelihood of a reduction in the strength of the THC. In this experiment we impose a reduction of the THC consistent with earlier experiments with the Hadley Centre coupled model and study the atmospheric response. The current phase of the project uses the Hadley Centre atmospheric model in conjunction with a simplified thermodynamic ("slab" ocean) which comprises a single layer ocean with prescribed heat and salinity transports. We impose surface fields which reflect the fully-coupled model's response to an imposed THC slowdown. The experiment is thus consistent with previous coupled model work with the same model at the same resolution. The essence of our THC experiment is to look at how the atmosphere would respond to such changes in the ocean, given a THC slowdown. Because (at this stage) we are only using a slab ocean (this will change in later phases of the project) we cannot yet probe feedbacks between the dynamical responses of the atmosphere back on to the ocean.

Motivation of the THC Experiment

The motivation behind the THC expt is to look at the sensitivity of the THC to anthropogenic climate forcing. Rapid climate changes have occurred in the geological recent past, and their coincidence in time with the creation of the North Atlantic Deep Water formation, suggests an active role of the THC in these rapid climate changes. Modelling results show a wide range of responses of the THC to high latitude warming and freshening, characteristic of global warming scenarios. Many models indicate a modest weakening of the THC, but some models produce a substantial breakdown of the THC under sufficiently strong forcing.

The uncertainty regarding the response of the THC to anthropogenic forcing is crucial in identifying and understanding the physical processes which control the stability of the THC. By now it is generally accepted that past changes in the THC have been triggered by large amounts of freshwater discharge from continental ice sheets in the North Atlantic. However, in the future, enhancements in the hydrological cycle may change the freshwater budget in the North Atlantic sufficiently to induce entirely different dynamics of the THC. In this context, it is not unlikely that important components of the climate system are remotely controlled. [An example of this is the suggested impact of the SST pattern in the Pacific on the freshwater budget in the North Atlantic, and consequently on the THC.] Yet another motivation to study the stability of the THC is the evidence compiled by models of various complexity, that the THC may not be far away from an instability threshold and that we may be probably approaching it as a result of greenhouse warming.

Full Description of the THC experiment

A key determinant of possible changes in the THC over the coming century is the atmospheric hydrological cycle response both to externally driven (predominantly CO₂-induced) temperature changes and to THC changes themselves. The hydrological cycle response to CO₂, particularly the extent of freshwater forcing change in the North Atlantic, determines the size of what is likely to be the largest externally imposed forcing on the THC over the coming decades. The hydrological cycle response to surface heat fluxes accompanying any THC change (whether internal or externally generated) determines whether the atmosphere acts to reinforce or damp the development of ocean circulation anomalies.

This is an area of considerable uncertainty at present, for two main reasons.

1. Precipitation changes are extremely sensitive to the details of underdetermined parameterisations in models, particularly at the regional level, reflected in the much wider spread of precipitation responses to increasing CO₂ relative to temperature responses in, for example, the CMIP-2 model inter-comparison project.
2. The mechanisms controlling the large-scale inter-annual hydrological cycle response to external forcing are such that most of the precipitation changes observed over the 20th century have, in contrast to recent temperature changes, been driven by natural (shortwave) forcing. Hence, the recent observational record provides a much less direct constraint on future precipitation changes than it does on future temperature trends. The balance between shortwave forcing, longwave forcing and thermal response will almost certainly change substantially over the next 30 years relative to the past 30 years, leading to much greater uncertainty in future precipitation changes relative to future temperature changes.

Previous model inter-comparison results make clear that any study of the large-scale hydrological cycle response to external forcing must account for model uncertainty. “Perfect-model” studies that are based solely on one specific representation of the atmosphere-ocean system miss, by construction, what is likely to be the most important source of uncertainty in the problem. Accounting for model uncertainty in climate prediction is still in its infancy, but recent years have seen considerable progress with the development of the first “perturbed physics” ensemble forecasting systems for the analysis of the response to anthropogenic (CO₂) forcing. This project will be the first to extend the perturbed-physics ensemble methodology to study the role of the hydrological cycle in possible rapid climate change.

Methodology:

In essence, our methodology extends the climateprediction.net project, using distributed computing to build a perturbed-physics ensemble simulation of the range of responses to increase CO₂, to recent studies by Dong and Sutton (2002) and Palmer (2002) examining the response of a particular atmosphere model to changes in THC. Under climateprediction.net, a current climate-resolution atmospheric general circulation model (the standard version of the HadAM3 model, with longitude/latitude resolution of 3.75 by 2.5 degrees and 19 levels in the vertical) is coupled to a simple thermodynamic “slab” ocean model. The properties of the model atmosphere are then changed using some combination of perturbations to over 20 parameters (including switches that allow entire model sub-systems to be activated or deactivated) and the resulting perturbed model is distributed to a volunteer participant in the project to be run on a personal computer.

The standard climateprediction.net experiment comprises a 15-year integration during which sea-surface temperatures are strongly relaxed back to observed present-day conditions and the Ocean Heat Flux Convergence (OHFC) field is calculated to balance the resulting down-welling surface heat flux from the atmosphere. This is followed by a 15-year “control” phase with pre-industrial CO₂ levels, and a 15-year “doubled-CO₂” phase in which CO₂ levels are increased to 560ppmv. A standard diagnostic set comprising approximately 0.5Gb of output is archived on the participants personal computer while a set of summary diagnostics (~5Mb per experiment) is automatically uploaded to one of the projects’ servers at the end of the experiment. These summary diagnostics provide an indication of the range of behaviour across the ensemble as well as highlighting particularly interesting parameter combinations for which we can either request the full archive to be uploaded (if the participant’s internet connection allows) or repeat the run in-house.

In this revised experiment, an additional OHFC perturbation will be applied at the end of the doubled-CO₂ phase of the standard experiment to represent the change in net ocean-atmosphere surface heat flux that might result from a substantial reduction in the THC and the model integrated for a further 15 years. Although most models will not all have reached equilibrium by the end of this period, feedbacks in a slab-ocean set-up are sufficiently close to linear in the temperature change for the degree of disequilibrium to be inferred from the time-history and energy budget of the response. As an additional check, however, the OHFC perturbation phase will be started from the end of the 14th year of the doubled-CO2 phase thereby ensuring a 1 year overlap between the end of one phase and the beginning of the next. With an initial condition ensemble this overlap will provide information about linearity of the temperature response when the OHFC perturbation is applied.

This heat flux perturbation is derived directly from the work of Palmer (2002), who used a multiple regression analysis to separate out the OHFC changes associated with wind-stress curl anomalies (which affect any index of THC but are not directly relevant to the thermo-haline signal) from the OHFC anomaly associated with THC fluctuations in the HadCM3 coupled model control variability.

Palmer (2002) performed an experiment in which this OHFC response-pattern was scaled to correspond to a ~50% reduction in THC magnitude from HadCM3 control values and obtained a ~2K global mean cooling in response, as compared to Vellinger and Wood (2002) who induced a near-complete THC shut-down associated with a ~4K global mean cooling. We propose initially using double Palmer (2002)’s perturbation, although the perturbed-physics ensemble set-up makes imposing a variety of OHFC perturbations very straightforward, and sensitivity of response to the imposed pattern and amplitude will be explored in the course of this project. Following Palmer (2002), the imposed OHFC perturbation is seasonally varying.

Comparison of the mean precipitation response in the region of the North Atlantic where Vellinga and Wood (2002) imposed a freshwater forcing to induce an THC shutdown reveals that the magnitude (and possibly even the sign) of the atmospheric hydrological-cycle feedback on THC changes is highly sensitive to underdetermined aspects of atmosphere model formulation. Under this project, we will use diagnostics returned from the perturbed-physics ensemble to identify parameter combinations which result in atmospheres that are (1) sensitive to CO₂ forcing; (2) sensitive to THC changes with the precipitation response giving a positive feedback and (3) relatively realistic in terms of their base climate. We will assess to what extent current observations allow us to constrain the ensemble in these “pathological” parameter-space directions and provide a range of representative statistical models of possible atmospheric responses to internal ocean variability, CO₂ and THC changes for use as upper boundary conditions in ocean THC predictability studies.

Figure 1.(a) DJF mean values of the OHFC anomaly imposed in the climateprediction.net client to simulate the impact of a ~100% reduction in AMOC; (b) Temperature response to this OHFC perturbation averaged over years 8-15 of a 15-year simulation following the perturbation; (c) Precipitation response from the same model-version as (b); (d) Precipitation response from another model-version with different, but also physically plausible, values of model parameters.