The Antarctic ice sheet is much less likely to become unstable and cause a dramatic rise in sea level over the coming centuries if the world follows policies that keep global warming below a key target of the agreement of Paris on the climate of 2015, according to a study co-authored by Rutgers.
But if global warming exceeds the target – 2 degrees Celsius (3.6 degrees Fahrenheit) – the risk of melting ice shelves around the perimeter of the ice sheet would increase dramatically and their collapse would trigger a rapid melting of the ice sheet. Antarctic. That would translate to at least 0.07 inches of global average sea level rise per year in 2060 and beyond, according to the journal’s study. Nature.
This is faster than the average rate of sea level rise over the past 120 years and, in vulnerable coastal locations like downtown Annapolis, MD, has led to a dramatic increase in number of days of extreme flooding.
A global warming of 3 degrees Celsius (5.4 degrees Fahrenheit) could lead to a catastrophic rise in sea level due to the melting of Antarctica – an increase of at least 0.2 inches per year worldwide after 2060, on average.
“The collapse of the ice sheet is irreversible over thousands of years, and if the Antarctic ice sheet becomes unstable, it could continue to retreat for centuries,” said co-author Daniel M. Gilford, post-doctoral fellow associated with the Rutgers Earth System Science & Policy Lab. led by co-author Robert E. Kopp, professor in the Department of Earth and Planetary Sciences in the School of Arts and Sciences at Rutgers University-New Brunswick. “It does not matter if emission mitigation strategies such as removing carbon dioxide from the atmosphere are employed.”
The Paris Agreement, concluded at a United Nations conference on climate change, aims to limit the negative impacts of global warming. Its goal is to keep the increase in global average temperature well below 2 degrees Celsius above pre-industrial levels, while continuing efforts to limit the increase to 1.5 degrees Celsius (2.7 degrees Fahrenheit). . The signatories pledged to eliminate net global carbon dioxide emissions in the second half of the 21st century.
Climate change due to human activities is causing sea level to rise, and predicting how Antarctica will contribute to that rise in a warmer climate is a difficult but critical challenge. How the ice caps might respond to warming is not well understood, and we do not know what the ultimate global political response to climate change will be. Greenland is losing ice at a faster rate than Antarctica, but Antarctica contains nearly eight times as much ice above ocean level, which is equivalent to 190 feet of global average elevation of the sea level, the study notes.
The study explored how Antarctica could change over the next century and beyond, depending on whether the Paris Agreement temperature targets are met or exceeded. To better understand how the ice cap might react, scientists trained a state-of-the-art ice cap model with modern satellite observations, paleoclimatic data, and a machine-learning technique. They used the model to explore the likelihood of a rapid retreat of the ice sheet and collapse of the West Antarctic ice sheet under different global greenhouse gas emissions policies. tight.
Current international policies are expected to result in a warming of around 3 degrees Celsius, which could thin the protective ice shelves of Antarctica and trigger a rapid retreat of the ice sheet between 2050 and 2100. In this scenario, strategies Geoengineering such as removing carbon dioxide from the atmosphere and sequestering (or storing) this would fail to prevent Antarctica’s worst contributions to global sea level rise.
“These results demonstrate the possibility that a catastrophic and unstoppable rise in sea level from Antarctica could be triggered if the temperature targets of the Paris Agreement are exceeded,” the study said.
Gilford said: “It is essential to be proactive in mitigating climate change now through active international participation in reducing greenhouse gas emissions and continuing to reduce proposed policies to achieve ambitious goals. of the Paris Agreement “.
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