See Level Rise: "The IPCC Understates What Is Going to Happen"
19 Jul, 2007 08:19 pm
Mark Meier is a professor emeritus of geological sciences. He explains his findings on the contribution of small glaciers and ice caps on sea level rise, published today in Science.
The majority of Sea-Level Rise by 2100 will originate from small glaciers and ice caps, and not the polar ice sheets, according to your study published in this week’s issue of Science.What are the figures in your study?
We are saying that glaciers and ice caps are gaining about 400 cubic kilometers of water to the ocean, which is raising the global sea level to about 1.1 millimeters per year. This rate is rising at about 12 cubic kilometers of additional water each year.
What other factors contribute to the rising of the ocean levels?
First, there is the warming of ocean water, which causes it to expand. Secondly, Greenland and Antarctic ice sheets are contributing a little extra water from land into the ocean.
What are the ratios between the two?
In terms of millimeters per year the IPCC reports that the current warming of the water is causing an expansion of about 1.6 millimeters per year. We say that the small glaciers are causing additional water that raises the sea level by about 1.1 millimeters per year. While the Greenland and Antarctic ice sheets are raising sea level by about 0.18 millimeters per year.
What are the prognostications up until 2100?
We suggest that the contribution to seawater by these small glaciers by 2100 will have caused a sea level rise of 100 to 240 millimeters. For the Greenland ice sheet we get a number that is close to that. The East and West Antarctic ice sheets combined give a number that is about 50 millimeters. For a global total we get a total of up to 560 millimeters of sea level rise due to this addition of new water by 2100.
But the IPCC report said that the total sea rise would be 200 to 500 millimeters. We are putting the water added to the ocean due to ice melt at even more than what the IPCC says the total rise will be. When you add the thermal expansion of the ocean, you get an even larger number. Therefore the IPCC understates what is going to happen.
Interview by: Christopher Le Coq
Mark Meier you are a Professor Emeritus of Geological Sciences at the University of Colorado, a fellow at the Institute of Arctic and Alpine Research
