os dejo esta reunion que tuvo lugar en el distrito de conlumbia
mirar bien los datos de temperaturas y lo que tiene marcados como maximo el IPCC.
DISTRICT OF COLUMBIA
April/May 2006 Newsletter
The Arctic is Melting: Does Congress Care?
Report of the April 2006 Meeting of the DC-AMS Chapter
The 25 April 2006 meeting of the DC Chapter of the American Meteorological Society (DC AMS) was held at the National Weather Service headquarters, Silver Spring, MD. Chapter member Stanley Doore gave members posters on the relationships of International System (metric or SI) derived units.
This month's topic was "The Arctic is Melting:Does Congress Care?". The invited guests were Dr. Robert Corell, lead author and chair of the Arctic Climate Impact Assessment 1 (ACIA), and Dr. Paul Higgins, Congressional Science Fellow of the American Meteorological Society (AMS). Both are authorities on modern climate change.
Dr. Corell emphasized the role that the Arctic plays in global climate. The Intergovernmental Panel on Climate Change (IPCC), in the moderate "B2 scenario" 2; predicted that the atmospheric level of CO2 will get to 621 ppm by the year 2100, which is double the value in the middle of the 20th Century, and will be increasing the global warming. Temperature reconstructions of the past 2000 years show that the Arctic climate is now warming faster than we have seen in the past, and that increasing greenhouse gases (especially CO2 ) resulting from human activities, may warm the Earth even more rapidly in the future. Analysis of the global mean temperature over the past 125 years shows that the global mean surface temperature has increased between 0.3o and 0.6oC, and that 2005 may have had the highest mean temperature on record. The IPCC 2001 report (
http://www.ipcc.ch/) states the global temperature must be kept less than 2°C above today's temperatures to avoid 'dangerous' interference in climate change. He expects that the 2007 report of the IPCC will peg the rate of temperature change at 2° to 3°C for a doubling of CO2. Dr. Corell showed a plot based on the NCAR Parallel Climate Model (PCM) suggesting that anthropogenic factors have contributed to global warming over the last 40 years, with a 95% confidence level.
Dr. Corell then looked at the role of the oceans. Rising global temperatures may well disrupt global transport of heat by ocean currents. Showing the work of James Hansen of NASA, he added that the earth absorbs more energy from the Sun than it is re-emitting. Ninety percent (90%) of this excess heat goes into warming the ocean. The oceans are the key to global energy balance. The oceans contain 97% of the earth's water, experience 86% of the evaporation, and are responsible for one-half of the transport of energy from the equatorial to the Polar regions. As stated above, the Earth has already warmed in modern times by about 0.6oC; the oceans have enough stored energy to increase the global temperature by yet another step of 0.6oC. Taken together, we are already 2/3 of the way to the IPCC's threshold of a 2oC increase. Corell spoke to the concern that Arctic climate change may lead to a shutdown of the Atlantic Ocean deep circulation; according to him a "redistribution" of currents is more likely than a "shutdown."
According to Dr. Corell, warming of the Arctic directly impacts some Indigenous Peoples and animals. Many towns around the Arctic Ocean are facing increased erosion and flooding due to ferocious storm surges, which were not a problem when ice was present. The community of Shishmaref, Alaska, which sits on an island only ½ mile wide, lost up to ¼ of the width of the island in recent years. Decreased sea ice threatens polar bears and some seal species with extinction. Steps are now being taken to put polar bears on the list of endangered species. Also, as CO2 rises in the atmosphere over the oceans, pH will decrease in the water. We have already seen a 30% increase in the acidity of the ocean, disrupting phytoplankton production.
Corell spoke of a 10o to 12oC warming in the Arctic over one century. Greenland is projected to warm 3o to 6oC. The area of the Greenland ice sheet that undergoes summer melting has increased on the order of 70% over the last 25 years -- water released from land-based frozen ice sheets and glaciers adds to the rise of sea level, unlike the melting of icebergs and sea ice. The complete melting of the Greenland ice sheet would lead to a 7 meter rise in sea rise. Coastal communities and facilities would face increasing exposure to storms. A one meter sea level rise could inundate Southern Florida and many coral atoll nations that only have 1 - 2 meters of topographic height.
Dr. Corell stated that the warming of the Arctic climate will have a tremendous effect on marine shipping and navigation: Russia and Canada are already planning for routine shipping through the Northwest Passage and along the Arctic shoreline. Major geopolitical issues in the Arctic Basin such as access, seaward claims, and boundary disputes remain unresolved.
His final remark was that the best we can do is to outline plausible paths to the future. For example, over 650 cities in the world, including 150 in the United States, have adopted Climate Plans.
The second speaker of the evening, Congressional Science Fellow Paul Higgins, remarked on climate legislation and policy. Proposed climate regulations have two approaches:
1. A cap-and-trade scheme that imposes limits on greenhouse-gas emissions while allowing companies to buy and sell the right to emit; and
2. An air pollution license fee scheme.
Examples of the former approach are the Kyoto accords, and the 1990 Clean Air Act. Higgins said that he favors the latter approach. Higgins outlined 3 obstacles to enacting meaningful climate legislation:
Misunderstanding of climate economics;
Those who benefit from the legislation are numerous but often unaware that they benefit. They are not organized, and thus are not powerful. Those who are harmed by legislation are usually well aware that they are hurt, are organized, and tend to be politically powerful.
A great fear that the US would act unilaterally, and a great desire that the US obtain international cooperation.
The meeting ended with a vigorous question-and-answer session.
Notes:
1. The Arctic Climate Impact Assessment was published by Cambridge University Press in 2004 and is available online at
http://www.acia.uaf.edu2. In the IPCC Report, the B2 storyline and family of scenarios describes a world in which the emphasis is on local solutions to economic, social, and environmental sustainability. It is a world with continuously increasing global population, intermediate levels of economic development, and less rapid and more diverse technological change. While the scenario is also oriented toward environmental protection and social equity, it focuses on local and regional levels.---Lauraleen O'Connor.
saludos
4628 Respuestas
1305019 Vistas