London: A new study has found that melt off from small mountain glaciers and ice caps will contribute about 12 centimetres to world sea-level increases by 2100.
Scientists from the University of British Columbia said the largest contributors to the projected world sea level increase are glaciers in Arctic Canada, Alaska and landmass bound glaciers in the Antarctic.
Glaciers in the European Alps, New Zealand, the Caucasus, Western Canada and the Western United Sates, though small absolute contributors to global sea-level rise, are projected to lose more than 50 percent of their current ice volume.
Currently, melt from smaller mountain glaciers and ice caps is responsible for a disproportionately large portion of sea level increases, even though they contained less than 1 percent of water in glacier ice.
The scientists arrived at their conclusions by modeling volume loss and melt off from 120,000 mountain glaciers and ice caps. It is one of the first to provide detailed projections by region.
However, their projections don`t include glacier calving - the production of icebergs.
“There is a lot of focus on the large ice sheets but very few global scale studies quantifying how much melt to expect from these smaller glaciers that make up about 40 percent of the entire sea-level rise that we observe right now,” said lead author Valentina Radic.
Increases in sea levels caused by the melting of the Greenland and Antarctic ice sheets, and the thermal expansion of water, are excluded from the results.
Radic and her colleague Regine Hock of the University of Alaska, Fairbanks, modeled future glacier melt based on temperature and precipitation projections from 10 global climate models used by the Intergovernmental Panel on Climate Change.
“While the overall sea level increase projections in our study are on par with IPCC studies, our results are more detailed and regionally resolved,” said Radic.
“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,” she said.
Global projections of sea level rises from mountain glacier and ice cap melt from the IPCC range between seven and 17 cm by the end of 2100.
Radic’s projections are only slightly higher - in the range of seven to 18 cm.
However, the new projections include detailed projection of melt off from small glaciers surrounding the Greenland and Antarctic ice sheets, which have so far been excluded from, or only estimated in, global assessments.
The study is published in Nature Geoscience. (ANI)