The combined analysis was carried out by a team of 89 scientists from 50 international organisations, who combined the findings of 26 ice surveys. About a third of the total sea level rise now comes from Greenland and Antarctic ice loss. Just under half comes from the thermal expansion of warming ocean water and a fifth from other smaller glaciers.
But the latter sources are not accelerating, unlike in Greenland and Antarctica. Shepherd said the ice caps had been slow to respond to human-caused global heating. Greenland and especially Antarctica were quite stable at the start of the s despite decades of a warming climate. Shepherd said it took about 30 years for the ice caps to react. Now that they had a further 30 years of melting was inevitable, even if emissions were halted today. The Ice Sheet Mass Balance Intercomparison Exercise team combined 26 surveys to calculate changes in the mass of the Greenland and Antarctic ice sheets between and The team calculated that the two ice sheets together lost 81 billion tons per year in the s, compared with billion tons of ice per year in the s—a sixfold increase.
All total, Greenland and Antarctica have lost 6. The resulting meltwater boosted global sea levels by 0. Together, the melting polar ice sheets are responsible for a third of all sea level rise. Of this total sea level rise, 60 percent resulted from Greenland's ice loss and 40 percent resulted from Antarctica's. The breadth of such findings underpinned sea level projections in the latest IPCC report. The Antarctic ice sheet once again represented the greatest source of uncertainty in these projections.
The shaded area reflects the large uncertainties in models using the same basic data sets and approaches. The dotted line reflects deep uncertainty about tipping points and thresholds in ice sheet stability.
IPCC reports are intended to guide global policy-makers in coming years and decades. But the uncertainties about ice melt from Antarctica limit the usefulness of projections by the IPCC and others.
Read more: This is the most sobering report card yet on climate change and Earth's future. Future sea level rise poses big challenges such as human displacement, infrastructure loss, interference with agriculture , a potential influx of climate refugees , and coastal habitat degradation.
Significant investment across these projects is needed. Sea levels will continue rising in the coming decades and centuries. Ice sheet projections must be narrowed down to ensure current and future generations can adapt safely and efficiently.
Portsmouth Climate Festival — Portsmouth, Portsmouth. Edition: Available editions United Kingdom.
0コメント