There is no longer any reasonable doubt that human activities are warming the planet at a dangerous rate, according to a new worldwide assessment of climate science released today by the authoritative Intergovernmental Panel on Climate Change.
.
With at least 90 percent certainty, the IPCC's "Summary For Policymakers" concludes human-generated greenhouse gases account for most of the global rise in temperatures over the past half century. Hundreds of scientists from 113 countries prepared the report, which represents the most comprehensive overview of scientific climate research since 2001.
Climate Change 2007 Report (pdf)
.
Science: Global Climate Report Washington Post staff writer Juliet Eilperin will be online to discuss the global climate change report issued on Friday by the Intergovernmental Panel on Climate Change.
"The observed widespread warming of the atmosphere and ocean, together with ice-mass loss, support the conclusion that it is extremely unlikely that global climate change of the past 50 years can be explained without external forcing, and very likely that is not due to known natural causes alone," the report stated.
The report suggests that it is "very likely" that hot days, heat waves and heavy precipitation will become more frequent in the years to come, and it is "likely" future tropical hurricanes and typhoons will become more intense. Arctic sea ice will disappear "almost entirely" by the end of the century, it says, while snow cover will contract worldwide.
While the summary does not produce any ground-breaking observations -- it reflects a massive survey of the world's peer-reviewed literature on global warming in recent years -- it is significant because it represents the definitive international scientific and political consensus on climate science. It provides a much stronger assessment of global warming than the panel's previous report in 2001, which said it was "likely," meaning a 66 percent chance, that human activity accounted for the warming recorded over the last 50 years.
Governments and scientific organizations across the globe nominate scientists to produce and review the IPCC assessment under the auspices of the United Nations; ultimately, a group of 30 government officials developed and developing countries chose who would write the report. A group of key authors and government officials gathered in Paris this week to finalize the document, which reflects years of work.
"Every government in the world signed off on this document, including the U.S." said the World Bank's chief scientist Robert Watson, who chaired the IPCC's last round of deliberations. Watson added that compared to the 2001 report, "The difference is now they have more confidence in what they're doing."
The earth's average temperature will increase between 3.2 and 7.8 degrees Fahrenheit (1.8 and 4 degrees Celsius) over the next century, according to the report, while global sea levels will rise between 7 and 23 inches (18 and 59 centimeters) during that period.
Bush administration officials said today they welcomed the report, and emphasized that U.S. funding for climate research helped underpin its conclusions.
"Without the great work of our scientists, the advances in knowledge of our planet's climate that were documented in today's IPCC report would not have been possible," said Commerce Secretary Carlos M. Gutierrez.
But environmental advocates said the administration has not done enough to cap U.S. carbon emissions and urged Congress to act quickly in the wake of the IPCC's findings.
"The administration's proposals are at least a decade away.," said Angela Anderson, vice president for climate programs at the National Environmental Trust. "The promise of better technologies tomorrow shouldn't stop us from doing what we can today. Thankfully, political will in Congress is rising faster than temperature readings."
No comments:
Post a Comment