80 researchers have investigated the contribution of land ice to the 21st century sea level rise arising from the world’s glaciers and the Greenland and Antarctic ice sheets. Dr. Tamsin Edwards from King’s College London (Great Britain) is the lead author of the paper.
The study uses a large number of computer models combined with statistical techniques, making predictions for the latest socio-economic scenarios. To determine the future mass losses of mountain glaciers, the work of ten international research groups using a total of eleven different models was coordinated in Bremen. "This study incorporates the combined expertise of the global community of glacier modelers," explains the climate geographer Professor Ben Marzeion.
The results also contribute to the Intergovernmental Panel on Climate Change's Sixth Assessment Report, which will be published in fall this year.
The research predicts that if we limit global warming to 1.5°C, Greenland ice sheet losses would reduce by 70% and glacier losses by half. A prerequisite is that global warming is stopped at 1.5 degrees Celsius and not, as other possible IPCC scenarios calculate, at two or more degrees Celsius.
Sea Level Is Rising but Damage Can Be Restricted
Dr. Tamsin Edwards, Director of the King’s Climate Hub, says: “Ahead of COP26 this November, many nations are updating their pledges to reduce greenhouse gas emissions under the Paris Agreement. The global sea level will continue to rise, even if we halt all emissions now, but our research suggests we could limit the damage: If pledges were far more ambitious, central predictions for sea level rise from melting ice would be reduced from 25 cm to 13 cm in 2100, with a 95% chance of being less than 28 cm rather than the current upper end of 40 cm. This would mean a less severe increase in coastal flooding.”
Study Contributes to More Specific Prediction of Sea Level Rise
Glaciers and ice sheets are currently responsible for around half of global sea level rise, with most of the rest arising from expansion of the oceans as they warm. Previous predictions had used older emissions scenarios, and could not explore uncertainty about the future as thoroughly due to the limited number of simulations. This statistically based study updates the scenarios, and combines all sources of land ice into a more complete picture that predicts the likelihood of different levels of sea level rise.
Original publication: Tamsin Edwards et al: Projected land ice contributions to 21st century sea level rise. Nature 2021. DOI: 10.1038/s41586-021-03302-y
Prof. Dr. Ben Marzeion
Institute of Geography
MARUM – Center for Marine Environmental Sciences
University of Bremen
Email: ben.marzeionprotect me ?!uni-bremenprotect me ?!.de