The massive ice sheets of Antarctica and Greenland have long been considered the major suspect contributors of sea level rise in the coming century.
But a study published last month in the journal Nature Geoscience indicates that sea level rise this century may be more of a “death from a thousand cuts” from smaller mountain glaciers and ice caps, particularly those in the Alps and New Zealand. In those regions, researchers project glaciers will lose more than 70 percent of their ice by 2100.
The smaller glaciers scattered across the planet comprise less than one percent of all fresh water bound in glacial ice, but have accounted for nearly half the sea level rise in the past 50 years, according to the report. By century’s end these small glaciers and ice caps will contribute between 8.7 to 16.1 centimeters to sea level, more than expected given their relative small size. Total projected sea level rise is 1 to 2 meters by 2100, most of which will come from the melting ice sheets of Greenland and Antarctica, and thermal expansion of seawater.
This latest study aligns with previous projections of sea level rise says Murray Simpson of Oxford Universiy:
“All studies since 2007 clearly show that, in total, sea levels will rise 1 to 2 meters by the end of the century,” said Simpson, a senior research associate at Oxford’s Centre for the Environment.
Researchers simulated the ice loss of more than 2,000 ice caps and 120,000 mountain glaciers across the globe in response to 10 different climate models. While aggregate sea level projections are consistent with previous studies, lead author Valentina Radic emphasizes that “our results are more detailed and regionally resolved. This allows us to get a better picture of projected regional ice volume change and potential impacts on local water supplies, and changes in glacier size distribution.” Such resolution of data may help some regions the are particularly dependent on glacier runoff, such as Nepal and Bolivia, prepare for coming water shortages.
What is clear from the research, say Radic, is that “small glaciers and ice caps will be an important and increasing contributor to sea level rises this century”.