Antarctic ice sheet is more vulnerable to CO2 than expected

February 22, 2016

AMHERST, Mass. - Results from a new climate reconstruction of how Antarctica's ice sheets responded during the last period when atmospheric carbon dioxide (CO2) reached levels like those expected to occur in about 30 years, plus sediment core findings reported in a companion paper, suggest that the ice sheets are more vulnerable to rising atmospheric CO2 than previously thought.

Details appear in two papers in the current Proceedings of the National Academy of Sciences.

Researchers led by Edward Gasson and Robert DeConto at the University of Massachusetts Amherst, with colleagues at Pennsylvania State University and GNS Science, New Zealand, report results of a climate and ice sheet modeling study, while Richard Levy of New Zealand and colleagues with the National Science Foundation's Antarctic drilling program (ANDRILL), report their analyses of a 3,735-foot sediment core from McMurdo Sound to reconstruct the Antarctic ice sheets' history.

The authors state that taken together, the findings highlight that large changes in the Antarctic ice sheets may be possible at lower levels of atmospheric carbon dioxide than previous studies have shown.

Gasson explains that climate researchers have long sought to create a model that simulates conditions similar to those experienced during the early to mid-Miocene, as established by sediment core data. This was likely the last time atmospheric CO2 levels were slightly higher, at 500 parts per million (ppm), than the 400 ppm level reached just last year, and global average temperatures were about 3 to 4 degrees Celsius higher than today.

But this does not mean that melting Antarctic ice sheets will raise global sea levels immediately, the researchers say. "The ice sheets will take hundreds of years to respond, so although CO2 may be at the same level as during the Miocene in the next 30 years, it doesn't mean that they will melt in 30 years," Gasson adds.

Understanding how the huge Antarctic ice sheets will respond to such warming is a major goal for climate scientists. Gasson says, "We know that the Antarctic ice sheet will eventually melt if we burn all known fossil fuel reserves, raising sea levels by over 100 feet. What these two studies show is that the Antarctic ice sheet is also vulnerable to much lower levels of carbon dioxide than we thought possible before."

Previous attempts to simulate Antarctic ice sheet retreat have been inadequate because despite direct geological evidence that large swings in the extent of ice sheets driven by small changes in atmospheric CO2 occurred, it was difficult for computer simulations to model them.

Gasson and colleagues' model includes three key new strategies that improve the simulation. In particular, Gasson and colleagues use a component that captures feedbacks between the ice sheet and climate better than before. The UMass Amherst-led modeling team authors point out that their work "largely resolves the discrepancy between geological records and ice sheet models that had previously existed."
-end-


University of Massachusetts at Amherst

Related Ice Sheet Articles from Brightsurf:

Greenland ice sheet shows losses in 2019
The Greenland Ice Sheet recorded a new record loss of mass in 2019.

Warming Greenland ice sheet passes point of no return
Nearly 40 years of satellite data from Greenland shows that glaciers on the island have shrunk so much that even if global warming were to stop today, the ice sheet would continue shrinking.

Greenland ice sheet meltwater can flow in winter, too
Liquid meltwater can sometimes flow deep below the Greenland Ice Sheet in winter, not just in the summer, according to CIRES-led work published in the AGU journal Geophysical Research Letters today.

Ice sheet melting: Estimates still uncertain, experts warn
Estimates used by climate scientists to predict the rate at which the world's ice sheets will melt are still uncertain despite advancements in technology, new research shows.

Thousands of meltwater lakes mapped on the east Antarctic ice sheet
The number of meltwater lakes on the surface of the East Antarctic Ice Sheet is more significant than previously thought, according to new research.

Researchers discover ice is sliding toward edges off Greenland Ice Sheet
They found that ice slides over the bedrock much more than previous theories predicted of how ice on the Greenland Ice Sheet moves.

A clearer picture of global ice sheet mass
Fluctuations in the masses of the world's largest ice sheets carry important consequences for future sea level rise, but understanding the complicated interplay of atmospheric conditions, snowfall input and melting processes has never been easy to measure due to the sheer size and remoteness inherent to glacial landscapes.

Researchers discover more than 50 lakes beneath the Greenland Ice Sheet
Researchers have discovered 56 previously uncharted subglacial lakes beneath the Greenland Ice Sheet bringing the total known number of lakes to 60.

Ice-sheet variability during the last ice age from the perspective of marine sediment
By using marine sediment cores from Northwestern Australia, a Japanese team led by National Institute of Polar Research (NIPR) and the University of Tokyo revealed that the global ice sheet during the last ice age had changed in shorter time scale than previously thought.

Novel hypothesis goes underground to predict future of Greenland ice sheet
The Greenland ice sheet melted a little more easily in the past than it does today because of geological changes, and most of Greenland's ice can be saved from melting if warming is controlled, says a team of Penn State researchers.

Read More: Ice Sheet News and Ice Sheet Current Events
Brightsurf.com 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 Amazon.com.