Report: Sea levels could rise more than 3 feet by 2100A leaked draft of the latest UN climate change report warns that global sea levels could rise by more than three feet by the end of the century if greenhouse gas emissions continue unchecked.
The draft was written by the Intergovernmental Panel on Climate Change (IPCC), a body consisting of top climate and environmental scientists that won the Nobel Peace Prize in 2007.
The panel publishes a report every five or six years on the state of knowledge and scientific consensus about climate change, its causes and trends.
The report (PDF) is the fifth major publication by the panel since it was created in 1998. Reports by the panel are considered authoritative and influence governmental policy decisions.
According to the New York Times, the group does not conduct any original research. It acts only as a panel of experts who review and summarize recent scientific publications in the field and the overall consensus of experts on key issues affecting climate change.
The group came to international prominence after it won the Nobel Peace Prize in 2007. Its reports have come under heavy scrutiny and severe criticism by climate change deniers who reportedly identified some errors in the 2007 report.
Climate doubters have expressed skepticism about “climate change science.” Some say there is no evidence that the Earth is warming in spite of the fact that research experts say so. Others acknowledge the rising global temperatures but insist that human activity is not to blame. Still others admit that humans might have contributed but say that global warming is unlikely to follow the trajectory that researchers predict if green house gas admissions are not curtailed.
According to the New York Times, however, the international panel concluded in their latest report that they have become even more certain that human activity is to blame for the temperature increases since their 2007 report. The panel warned that if greenhouse gas emissions continue unchecked, sea levels could rise by more than three feet by the end of the century.
The group’s previous report had assessed the likelihood that global warming was the direct result of human activity as 90 percent. The latest report expressed even stronger conviction that most of the observed increases in global average surface temperature from 1951 to 2010 were caused by human activities.
The panel expressed confidence that human activities such as burning of fossil fuels are the major causes of atmospheric warming that is causing the rise in ocean temperatures, melting snow and ice and rising sea levels since the 1950s.
The report assessed the likelihood that human activities were behind rising global temperatures as 95 percent.
The observed apparent drop in the rate of global warming since 1998 in spite of rising greenhouse gas emissions has raised questions and fueled skepticism. However, the report (PDF) said the drop is only a short-term trend that would reverse. The scientists insisted that the facts about the process of climate change have been established and that the concerns being expressed about rising temperatures were justified. The report warned of the need for response to the threat of global warming.
Joe Romm of Climate Progress said the apparent drop “turns out to be only true if one looks narrowly at surface air temperatures, where only a small fraction of warming ends up.”
One of the issues of biggest concern to climate scientists is predicting the impact of climate change on average global sea levels. The new report, unlike the 2007, addressed the problem directly, saying that average sea levels could rise more than three feet by the end of the century if greenhouse emissions continue unchecked.
The report adopted an optimistic tone, saying that if the world’s governments respond effectively to the challenge by controlling emissions we could have much lower average sea level rise, as little as 10 inches by the end of the century. This is only a little greater than eight inches increase that occurred in the last century.
On the contrary if emissions are not brought under control the result would be at least 21 inches rise by 2100. The rise could be as high as three feet and threaten the lives of millions of people who live in the world’s major coastal cities such New York, London, Shanghai and Sydney.
The report also noted the difficulty researchers continue to face in their effort to model and predict climate change trends on a local scale, as distinct from large scale averages.
It addressed uncertainties about predicting how much temperature increases would result if carbon dioxide levels doubled.
While the 2007 report estimated the lowest possible increase at 3.6 degrees Fahrenheit, the latest draft says that although it could be as low as 2.7 degrees Fahrenheit it was not likely that it would be that low. Many researchers think it could be as high as 5 degrees Fahrenheit.
Researchers warn that an increase in average global temperature by 5 degrees Fahrenheit would have drastic effects on the global environment and that the local change in the poles could as high as 10 degrees.
According to researchers an increase of 5 degrees Fahrenheit could cause extensive melting of ice and widespread heat waves. It would also make it more difficult to grow food and might cause extinctions.
Some experts think that the decision of the panel to accept the low estimate of 2.7 degrees Fahrenheit was influenced by the sharp criticism it received from climate change deniers after its last report.
But a member of the panel, Christopher Field, a researcher at the Carnegie Institution for Science, defended the decision saying that the panel had to consider various views on the subject before coming to a decision.
He said: “I think that the IPCC has a tradition of being very conservative. They really want the story to be right.”
The Huffington Post refers to a recently published paper that shows that a sea level rise of about 15.75 inches by the middle of the century could lead to flooding in 136 of the world’s major coastal cities and that the resulting damage could cost $1 trillion annually.
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