Sea-level rise projections can improve with state-of-the-art model

October 07, 2020

Projections of potentially dramatic sea-level rise from ice-sheet melting in Antarctica have been wide-ranging, but a Rutgers-led team has created a model that enables improved projections and could help better address climate change threats.

A major source of sea-level rise could come from melting of large swaths of the vast Antarctic ice sheet. Fossil coral reefs jutting above the ocean's surface show evidence that sea levels were more than 20 feet higher about 125,000 years ago during the warm Last Interglacial (Eemian) period.

"Evidence of sea-level rise in warm climates long ago can tell us a lot about how sea levels could rise in the future," said lead author Daniel M. Gilford, a post-doctoral associate in the lab of co-author Robert E. Kopp, a professor in the Department of Earth and Planetary Sciences within the School of Arts and Sciences at Rutgers University-New Brunswick. "This evidence suggests that as climate change drives warming in the atmosphere and oceans, future global sea-level rise could reach considerable heights."

The study, published in the journal JGR: Earth Surface, delves into how paleoclimate evidence from about 125,000 years ago can be used to improve computer model projections of Antarctic ice-sheet collapse and sea-level rise. Such evidence is increasingly effective for improving projections, providing valuable insights into ice sheet vulnerability through at least 2150.

The study takes advantage of the similarities between past and potential future sea levels to train a statistical ice-sheet model, using artificial intelligence. The fast, simple, less expensive "emulator" - a form of machine learning software - is taught to mimic the behavior of a complex model that focuses on ice-sheet physics, enabling many more simulations than could be explored with the complex model alone. This avoids the costly run times of the complex ice-sheet model, which considers such phenomena as ice-sheet fractures due to surface melting and the collapse of tall seaside ice cliffs.

What may happen to the Antarctic ice sheet as the climate warms is the biggest uncertainty when it comes to global sea-level rise this century, the study notes. When combined with evidence of past sea levels, the new model can boost confidence in sea-level rise projections through at least 2150.

"If big swaths of the Antarctic ice sheet melted and collapsed about 125,000 years ago, when the polar regions were warmer than today, parts of the ice sheet may be similarly prone to collapse in the future as the climate warms, affecting our expectations of sea-level rise and coastline flooding over the next 130 years," Gilford said.

New estimates of sea levels about 125,000 years ago could be used to indicate whether, 75 years from now, Hurricane Sandy-like flooding (about 9 feet above ground level in New York City) is likely to occur once a century or annually along parts of the Northeast U.S. coastline. Improved projections could also be included in reports such as the Intergovernmental Panel on Climate Change's upcoming Sixth Assessment Report, likely helping officials and others decide how to address climate change threats.

Co-authors include Erica L. Ashe, a post-doctoral scientist in Kopp's lab, along with scientists at the University of Massachusetts Amherst, Pennsylvania State University and the University of Bremen.

Rutgers University

Related Climate Change Articles from Brightsurf:

Are climate scientists being too cautious when linking extreme weather to climate change?
Climate science has focused on avoiding false alarms when linking extreme events to climate change.

Mysterious climate change
New research findings underline the crucial role that sea ice throughout the Southern Ocean played for atmospheric CO2 in times of rapid climate change in the past.

Mapping the path of climate change
Predicting a major transition, such as climate change, is extremely difficult, but the probabilistic framework developed by the authors is the first step in identifying the path between a shift in two environmental states.

Small change for climate change: Time to increase research funding to save the world
A new study shows that there is a huge disproportion in the level of funding for social science research into the greatest challenge in combating global warming -- how to get individuals and societies to overcome ingrained human habits to make the changes necessary to mitigate climate change.

Sub-national 'climate clubs' could offer key to combating climate change
'Climate clubs' offering membership for sub-national states, in addition to just countries, could speed up progress towards a globally harmonized climate change policy, which in turn offers a way to achieve stronger climate policies in all countries.

Review of Chinese atmospheric science research over the past 70 years: Climate and climate change
Over the past 70 years since the foundation of the People's Republic of China, Chinese scientists have made great contributions to various fields in the research of atmospheric sciences, which attracted worldwide attention.

A CERN for climate change
In a Perspective article appearing in this week's Proceedings of the National Academy of Sciences, Tim Palmer (Oxford University), and Bjorn Stevens (Max Planck Society), critically reflect on the present state of Earth system modelling.

Fairy-wrens change breeding habits to cope with climate change
Warmer temperatures linked to climate change are having a big impact on the breeding habits of one of Australia's most recognisable bird species, according to researchers at The Australian National University (ANU).

Believing in climate change doesn't mean you are preparing for climate change, study finds
Notre Dame researchers found that although coastal homeowners may perceive a worsening of climate change-related hazards, these attitudes are largely unrelated to a homeowner's expectations of actual home damage.

Older forests resist change -- climate change, that is
Older forests in eastern North America are less vulnerable to climate change than younger forests, particularly for carbon storage, timber production, and biodiversity, new research finds.

Read More: Climate Change News and Climate Change Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to