Irreversible Warming

Sea Levels to Rise for Thousands of Years

Greenhouse gas emissions up to now have triggered an irreversible warming of Earth that will cause sea levels to rise for thousands of years to come.

The results come from a study, published today (Oct. 2) in IOP Publishing's journal Environmental Research Letters, which sought to model sea-level changes over millennial timescales, taking into account all of Earth's land ice and the warming of the oceans - something which has not been done before. The research showed that we have already committed ourselves to a sea-level rise of 1.1 meters by the year 3000 as a result of our greenhouse gas emissions up to now. This irreversible damage could be worse, depending on the route we take to mitigating our emissions. If we were to follow the high A2 emissions scenario adopted by the Intergovernmental Panel on Climate Change (IPCC), a sea-level rise of 6.8 meters could be expected in the next thousand years.

The two other IPCC scenarios analyzed by the researchers, the B1 and A1B scenarios, yielded sea-level rises of 2.1 and 4.1 meters respectively. "Ice sheets are very slow components in the climate system; they respond on time scales of thousands of years," said co-author of the study Professor Philippe Huybrechts. "Together with the long life-time of greenhouse gases in the atmosphere, this inertia is the real poison on the climate system: anything we do now that changes the forcing in the climate system will necessarily have long consequences for the ice sheets and sea level." In all of the scenarios that the researchers analyzed, the Greenland ice sheet was responsible for more than half of the sea level rises.

 

Thermal expansion of the oceans was the second highest contributor, and the contribution of glaciers and ice was only small.

 

Kemo D. 7

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