U.N. panel: Man-made global warming ‘unequivocal’ comment (0)
April 3, 2008
The most-often quoted authority on global climate change is the Intergovernmental Panel on Climate Change (IPCC), a scientific group established in 1988 by the United Nations to evaluate the risk of human-induced climate change. It was the IPCC that shared the 2007 Nobel Peace Prize with Al Gore, former vice president of the United States.
Since its inception, the panel has published four assessment reports — the most recent in 2007 — that reviewed climate research conducted around the world and summarized the findings.
Twelve key findings are summarized in the “Summary for Policymakers” document in “The Physical Science Basis,” a report from one of the three IPCC working groups released in February 2007. Among those findings:
1. “Global atmospheric concentrations of carbon dioxide, methane and nitrous oxide have increased markedly as a result of human activities since 1750 and now far exceed [preindustrial] values determined from ice cores spanning many thousands of years.”
2. “Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level.”
3. “[T]he warmth of the last [half-century] is unusual in at least the previous 1,300 years. The last time the polar regions were significantly warmer than present for an extended period (about 125,000 years ago), reductions in polar ice volume led to 4 to 6 [meters] of sea level rise.”
4. “Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.”
5. “Anthropogenic warming and sea level rise would continue for centuries due to the time scales associated with climate processes and feedbacks, even if greenhouse gas concentrations were to be [stabilized].”
6. “Some aspects of climate have not been observed to change.”
Criticisms of the four reports vary widely. Some of the earlier reporting brought the 2005 resignation of panel member Christopher Landsea, who complained that the process was scientifically unsound and motivated by preconceived agendas. There are also those who contend that the reports understate the dangers of global warming.
In late April 2007, after another working group’s report reaffirmed the panel’s predictions of increased hunger, drought, heat and rising ocean levels, the IPCC issued recommendations about solutions to forestall catastrophic climate change.
“We’re moving from two very sobering reports to what we can do about climate change. And we can do it,” Achim Steiner, head of the United Nations Environment Program, told Reuters news service at the time.
“Having shown us the path [toward] greater and greater problems, the IPCC raises our horizons to where the solutions lie and shows that they are within our grasp,” he said. (BP)