Antarctica had a slight increase in sea ice, mostly because of the cooling effect of the ozone hole, according to the British Antarctic Survey. At the same time, large chunks of ice shelves — adding up to the size of Delaware — came off the Antarctic peninsula.
While melting Arctic ocean ice doesn't raise sea levels, the melting of giant land-based ice sheets and glaciers that drain into the seas do. Those are shrinking dramatically at both poles.
Measurements show that since 2000, Greenland has lost more than 1.5 trillion tons of ice, while Antarctica has lost about 1 trillion tons since 2002, according to two scientific studies published this fall. In multiple reports from the Intergovernmental Panel on Climate Change reports, scientists didn't anticipate ice sheet loss in Antarctica, Weaver said. And the rate of those losses is accelerating, so that Greenland's ice sheets are melting twice as fast now as they were just seven years ago, increasing sea level rise.
Worldwide glaciers are shrinking three times faster than in the 1970s and the average glacier has lost 25 feet of ice since 1997, said Michael Zemp, a researcher at World Glacier Monitoring Service at the University of Zurich.
"Glaciers are a good climate indicator," Zemp said. "What we see is an accelerated loss of ice."
Also, permafrost — the frozen northern ground that oil pipelines are built upon and which traps the potent greenhouse gas methane — is thawing at an alarming rate, Burkett said.
Another new post-1997 impact of global warming has scientists very concerned. The oceans are getting more acidic because more of the carbon dioxide in the air is being absorbed into the water. That causes acidification, an issue that didn't even merit a name until the past few years.
More acidic water harms coral, oysters and plankton and ultimately threatens the ocean food chain, biologists say.
In 1997, "there was no interest in plants and animals" and how they are hampered by climate change, said Stanford University biologist Terry Root. Now scientists are talking about which species can be saved from extinction and which are goners. The polar bear became the first species put on the federal list of threatened species and the small rabbit-like American pika may be joining it.
More than 37 million acres of Canadian and U.S. pine forests have been damaged by beetles that don't die in warmer winters. And in the U.S. West, the average number of acres burned per fire has more than doubled.
The Colorado River reservoirs, major water suppliers for the U.S. West, were nearly full in 1999, but by 2007 half the water was gone after the region endured the worst multiyear drought in 100 years of record-keeping.
Insurance losses and blackouts have soared and experts say global warming is partly to blame. The number of major U.S. weather-related blackouts from 2004-2008 were more than seven times higher than from 1993-1997, said Evan Mills, a staff scientist at the Lawrence Berkeley National Lab.
"The message on the science is that we know a lot more than we did in 1997 and it's all negative," said Eileen Claussen, president of the Pew Center on Global Climate Change. "Things are much worse than the models predicted."
On the Net:
U.S. government's 2009 report on climate change impacts: http://tinyurl.com/usimpacts
Intergovernmental Panel on Climate Change 2007 report on changes already observed:
United Nations Framework Convention on Climate change: http://unfccc.int