Expert Assessment: Sea-Level Rise Could Exceed One Meter in This Century

News ID: 201799 Service: Science
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TEHRAN (Tasnim) - Sea-level rise in this century is likely to be 70-120 centimeters by 2100 if greenhouse-gas emissions are not mitigated, a broad assessment of the most active scientific publishers on that topic revealed.

The 90 experts participating in the survey anticipate a median sea-level rise of 200-300 centimeters by the year 2300 for a scenario with unmitigated emissions.

In contrast, for a scenario with strong emissions reductions, experts expect a sea-level rise of 40-60 centimeters by 2100 and 60-100 centimeters by 2300. The survey was conducted by a team of scientists from the US and Germany.

"While the results for the scenario with climate mitigation suggest a good chance of limiting future sea-level rise to one meter, the high emissions scenario would threaten the survival of some coastal cities and low-lying islands," Stefan Rahmstorf from the Potsdam Institute for Climate Impact Research said.

"From a risk management perspective, projections of future sea-level rise are of major importance for coastal planning, and for weighing options of different levels of ambition in reducing greenhouse-gas emissions."

Projecting sea-level rise, however, comes with large uncertainties, since the physical processes causing the rise are complex. They include the expansion of ocean water as it warms, the melting of mountain glaciers and ice caps and of the two large ice sheets in Greenland and Antarctica, and the pumping of ground water for irrigation purposes.

"It is therefore useful to know what the larger community of sea-level experts thinks, and we make this transparent to the public," lead author Benjamin Horton from the Institute of Marine and Coastal Sciences at Rutgers University in New Jersey said.

"We report the largest elicitation on future sea-level rise conducted from ninety objectively selected experts from 18 countries."

While we tend to look at projections with a focus on the relatively short period until 2100, sea-level rise will obviously not stop at that date. "Overall, the results for 2300 by the expert survey as well as the IPCC illustrate the risk that temperature increases from unmitigated emissions could commit coastal populations to a long-term, multi-meter sea-level rise," Rahmstorf added.

"They do, however, illustrate also the potential for escaping such large sea-level rise through substantial reductions of emissions."

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