A study by American space agency NASA has concluded that polar ice sheets are losing mass at an accelerated rate and much faster than previously predicted, further highlighting the need for immediate measures to mitigate the effects of global warming.

A study by American space agency NASA has concluded that polar ice sheets are losing mass at an accelerated rate and much faster than previously predicted, further highlighting the need for immediate measures to mitigate the effects of global warming.

The study concluded that the Greenland and Antarctic ice sheets are losing mass at a more accelerated pace than initially foreseen, indicating that sea level rise might be happening faster than previously expected.

The study also suggests that ice loss is a more dominant contributor to global sea level rise than the Earth's mountain glaciers and ice caps. Moreover, this process is happening much sooner than model forecasts have predicted.

One of the findings of the 18 year long study is that in 2006, on average the two sheets lost a combined mass of 475 gigatonnes (Gt) a year. This loss is enough to raise global sea level by an average of 1.3 millimeters a year. In addition, the two ice sheets lose ice at an increasing rate: loss from the Greenland sheet is increasing by 21.9Gt per year and the Antarctic sheet is losing 14.5Gt each year.

As ice sheets hold more ice mass than mountain glaciers these findings are not surprising according to lead author Dr Eric Rignot who said, “what is surprising is this increased contribution by the ice sheets is already happening. If present trends continue, sea level is likely to be significantly higher than levels projected by the United Nations Intergovernmental Panel on Climate Change in 2007.”

If the ice sheets continue to melt at the current rate for the coming four decades, the authors predict that the total loss of the Greenland and Antarctic sheets could raise sea level by 15 centimeters by 2050. When taking into consideration predicted seas level rise from glacial ice caps (8 centimeters) and ocean thermal expansion (9 centimeters) total sea level rise could reach 32 centimeters by that same date.

This study sheds light on the potential contribution of ice sheets to sea level rise, however the authors stress that considerable uncertainties remain in estimating future ice loss acceleration.

MARITIME MEASURES TO REDUCE EMISSIONS

Seas At Risk has been working on the mitigation of greenhouse gas emissions from maritime activities (shipping and fishing) since 2007. According to research done for Seas At Risk in 2009, reducing ship speed could deliver immediate emission cuts of up to 30%, and changing from active to passive gear in fisheries could also reduce fuel consumption significantly, depending on the type of fishery.

In light of the dire scenarios posed by climate change and sea level rise, it is crucial that measures to reduce greenhouse gas emissions from all human activities are rapidly implemented.

For more information on the study

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