Melting ice threatens sea-level rise
The rumblings of global warming are echoing across Greenland. Groups of scientists studying ancient climate, tweaking computer models of future climate and even listening to earthquakes add to the evidence that global warming is melting polar ice, according to a series of papers in this week’s issue of the journal Science.
At the current rate of rising temperatures, by the year 2100 Arctic summers could be as warm as they were 130,000 years ago. Back then, in a time known as the last interglacial, the oceans were 20 feet higher than they are now.
That does not mean the researchers are predicting a 20-foot ocean rise by the end of this century; more like a couple of feet, they think. But such a warming is expected to accelerate melting of the polar ice and could lead to considerable additional sea-level rise, they said.
At current rate that Earth’s temperature is rising, by 2100 it will probably be 4 degrees warmer than it is now, with the Arctic at least as warm as it was 130,000 years ago, reports a research group led by Jonathan T Overpeck of the University of Arizona.
Computer models indicate that warming could have a substantial impact on melting of the polar ice sheets, according to researchers led by Bette Otto-Bliesner of the National Center for Atmospheric Research.
Melting could raise sea levels by 1 foot to 3 feet over the next 100 years to 150 years, she said.
Otto-Bliesner and Overpeck worked together on looking at the ancient climate and assessing whether or not modern computer models correctly reflect those earlier times.
• Increase in greenhouse gases in the atmosphere over the next century could
raise Arctic temperatures as much as 5 degrees to 8 degrees
• The warming could raise global sea levels by upto 3 feet this century through
a combination of thermal expansion and melting of polar ice
• Researchers say that a modest global warming may put the Earth in danger
zone for a major sea level rise due to deglaciation of one or both ice sheets