Ice sheet melting may be slow, but it’s inexorable
By Summit Voice
SUMMIT COUNTY — Study after study has been done on how global warming will affect sea level, and it appears that, no matter how you slice and dice it, coastal areas will see significant impacts during the coming centuries.
In one of the latest research projects, scientists tried to factor in all of the Earth’s ice, including some 200,000 glaciers worldwide, concluding that a sea-level rise of 1.1 (about 3.5 feet) meters by the year 3000 is inevitable.
Modeling sea-level rise is challenging because the ice sheets are slow components of the climate system, but the best available data suggests that unchecked emissions of greenhouse gases will result in a much greater rise in sea level — up to 6.8 meters in the next 1,000 years.
“Ice sheets are very slow components in the climate system; they respond on time scales of thousands of years,” said co-author of the study Professor Philippe Huybrechts.
“Together with the long life-time of greenhouse gases in the atmosphere, this inertia is the real poison on the climate system: anything we do now that changes the forcing in the climate system will necessarily have long consequences for the ice sheets and sea level.”
In all of the scenarios that the researchers analyzed, the Greenland ice sheet was responsible for more than half of the sea level rise; thermal expansion of the oceans was the second highest contributor, with melting glaciers contributing only a small percentage.
The researchers believe this is the first study to include glaciers, ice caps, the Greenland and Antarctic ice sheets and the thermal expansion of the oceans into a projection of sea-level rises.
The polar ice sheets are not normally included into projections due to computational constraints, while researchers often find it difficult to account for the 200 000 individual glaciers that are found all over the world in very different climatic settings.
“Ultimately the current polar ice sheets store about 65 metres of equivalent sea level and if climatic warming will be severe and long-lasting all ice will eventually melt,” Huybrechts said.
“Mankind should limit the concentration of greenhouse gases at the lowest possible level as soon as possible. The only realistic option is a drastic reduction of the emissions. The lower the ultimate warming will be, the less severe the ultimate consequences will be,” he concluded.