Arctic Melting Fast; May Swamp U.S. Coasts by 2099
Date: Tuesday, November 09, 2004 @ 20:02:34 GMT
for National Geographic News
November 9, 2004
Scientists have determined that the ice in Greenland and the Arctic is melting so rapidly that much of it could be gone by the end of the century. (See photos from the Arctic.)
The results could be catastrophic for polar people and animals, while low-lying lands as far away as Florida could be inundated by rising sea levels.
The Arctic Climate Impact Assessment was released yesterday. It will be discussed by the Arctic Council (the governments of Canada, Denmark, Finland, Iceland, Norway, the Russian Federation, Sweden, and the U.S., as well as six indigenous-peoples organizations) at a meeting in Iceland today.
The four-year study of the Arctic climate involved an international team of more than 300 scientists. They used a number of climate models and made a "moderate estimate" of future emissions of carbon dioxide and other greenhouse gases that are widely believed to be contributing to the recent warming trend of the Earth's climate.
The study concluded that in Alaska, western Canada, and eastern Russia, average temperatures have increased as much as 4 to 7 degrees Fahrenheit (3 to 4 degrees Celsius) in the past 50 years, nearly twice the global average. Temperatures are projected to rise 7 to 13 degrees Fahrenheit (4 to 7 degrees Celsius) over the next hundred years.
The rising temperatures are likely to cause the melting of at least half the Arctic sea ice by the end of the century. A significant portion of the Greenland ice sheet—which contains enough water to raise the worldwide sea level by about 23 feet (about 7 meters)—would also melt.
Computer models project how the Arctic ice cap may melt over the next century. The blue perimeter (marked by arrows) is actual ice in September 2002. The top illustration projects how the ice may shrink by 2030, the middle shows what may be left by 2060, and the bottom indicates what it could look like in 2090. Some computer models project all the ice will be gone within a century. A combination of computer models indicates that at least half of today's ice cover will have melted within a hundred years.
The consequences of such a massive meltdown of northern ice would be dramatic, according to the study.
• Low-lying coastal areas in Florida and Louisiana could be flooded by the sea. A 1.5 feet (50-centimeter) rise in sea level could cause the coastline to move 150 feet (45 meters) inland, resulting in substantial economic, social, and environmental impact in low-lying areas.
• The health and food security of some indigenous peoples would be threatened, challenging the survival of some cultures.
• Should the Arctic become ice-free in summer, it is likely that polar bears and some seal species would become extinct.
• The melting of so much ice, and the resulting addition of so much fresh water to the ocean, could impact the circulation of currents and affect regional climate.
Science and Policy
Susan Joy Hassol is an independent global warming analyst and author of the Arctic Climate Impact Assessment (ACIA) synthesis report Impacts of a Warming Arctic.
The assessment was four years in the making, made possible by the work of some 300 scientists from nations around the world.
"We found that scientific observations and those of indigenous people over many generations are meshing," Hassol said from her Denver office. "Sea ice is retreating, glaciers are reducing in size, permafrost is thawing, all [these indicators] provide strong evidence that it has been warming rapidly in the Arctic in recent decades."
As the Arctic evolves, climate around the world may be severely altered.
"The Arctic is the air conditioner for the world and we're looking at having a less efficient air conditioner," Hassol noted.
The report strived to stay out of the realm of policy but certainly gives decision makers some food for thought.
"I think that, from a scientific point of view, we try to present facts," she said. "It really is a fact that in order to slow climate change we need to start now. A climate system is like a supertanker, you can't turn on a dime so you have to turn the wheel now to avoid that iceberg [far] ahead."
Mark Serreze is a polar sea ice expert at the University of Colorado, Boulder. He's seen dramatic Arctic changes over the past 25 years.
"What's really interesting is that the past three summers (2002, 2003, and 2004) have been characterized by record or near record minimums [of total Arctic sea ice area]," Serreze said. "It begs the question: Have we approached a threshold beyond which large parts of the ice are unable to survive the summer? We don't know."
Serreze believes the ACIA findings illustrate that at least some Arctic changes are due to global warming, but cautions that the extent is difficult to discern.
"The Arctic is changing and changing rapidly, there is absolutely no doubt about that," he said. "It's the attribution that is difficult. You always have to remember the climate system, and the Arctic in particular, are inherently variable. It's difficult to separate natural variability from greenhouse gasses. It's not black-and-white."
People Are Already Affected
"The impacts of global warming are affecting people now in the Arctic," said Robert Corell, chairperson of the Arctic Climate Impact Assessment, in a news release. "The Arctic is experiencing some of the most rapid and severe climate change on Earth. The impacts of climate change on the region and the globe are projected to increase substantially in the years to come."
In a separate statement released with the assessment, the Arctic indigenous peoples said they are asking the eight Arctic countries to use the assessment to show leadership in the field of global warming.
"Everything is under threat," said Chief Gary Harrison of the Arctic Athabaskan Council. "Our homes are threatened by storms and melting permafrost, our livelihoods are threatened by changes to the plants and animals we harvest. Even our lives are threatened, as traditional travel routes become dangerous."
"The Arctic is the early warning for the rest of the world," said Sheila Watt-Cloutier of the Inuit Circumpolar Conference. "What happens to the planet happens first in the Arctic. Protect the Arctic and we save the planet. … We must all take what action we can to slow the pace of climate change, while there is still time."
The indigenous peoples are also asking for help with adapting to global warming impacts.