Ozone depletion increases Antarctic snowfall, partially mitigates ice sheet loss

Ozone layer depletion has increased snowfall over Antarctica in recent decades, partially mitigating the ongoing loss of the continent's ice sheet mass, new University of Colorado Boulder research finds.

The findings, published in the journal Geophysical Research Letters, show a distinct signal linking stratospheric ozone loss above Antarctica with increased precipitation, even as those gains have been outpaced by an even greater ice loss rate due to warming oceans, contributing to sea level rise. The Antarctic Ice Sheet is the world's largest ice sheet and freshwater reservoir, containing the potential for hundreds of feet of sea level rise if all ice were to melt.

"Calving icebergs and melting ice shelves have gotten lots of attention because they're the most visible impact of ongoing climate change to Antarctica," said Jan Lenaerts, lead author of the research and an assistant professor in CU Boulder's Department of Atmospheric and Oceanic Sciences. "But the input side of the equation, which is precipitation falling in the form of snow, hasn't drawn the same level of study."

An ozone "hole," or a seasonal thinning of the ozone layer, forms above Antarctica in the austral summer, influencing atmospheric circulation and creating stronger circumpolar westerly winds.

While previous research has outlined some aspects of the relationship between ozone depletion and the climate of the southern hemisphere, the new study co-authored by Lenaerts, Jeremy Fyke of Los Alamos National Laboratory and Brooke Medley of NASA's Goddard Space Flight Center Cryospheric Sciences Laboratory has analyzed the effect on Antarctica specifically.

The results complement a separate NASA-led study, which was led by Medley and published in the journal Nature Climate Change, which uses observations from ice cores to show that Antarctic snowfall has increased in the last 200 years and especially so in the past 30 years, suggesting that precipitation changes can be linked to man-made causes such as greenhouse gas emissions as well as the ozone hole.

In order to pinpoint the effect of ozone loss on Antarctic snowfall, Lenaerts and his colleagues compared two sets of eight climate modeling simulations, one set with observed ozone levels and one set with ozone values kept constant at levels before the ozone hole started, allowing the researchers to isolate the signal relative to natural climate variability.

The comprehensive analysis, which encompassed the years 1955-2005, revealed increased Antarctic precipitation during the austral summer that can be attributed to lower levels of stratospheric ozone, and which has in part buffered ice sheet mass loss.

Paradoxically, while the results suggest that ozone depletion (previously the focus of global conservation efforts such as the 1987 Montreal Protocol) helps to partially mitigate sea level rise by increasing Antarctic precipitation, those mass gains have been more than offset by increasing iceberg calving and melting.

"The pace at which snowfall is increasing is not keeping up with the ocean-induced losses," Lenaerts said. "The Antarctic Ice Sheet is still losing mass."

Research paper

Related Links
University of Colorado at Boulder
Beyond the Ice Age

Tweet

Thanks for being there;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Monthly Supporter
$5+ Billed Monthly

paypal only

SpaceDaily Contributor
$5 Billed Once

credit card or paypal

More Glaciers in East Antarctica Are Waking Up
Greenbelt MD (SPX) Dec 11, 2018
East Antarctica has the potential to reshape coastlines around the world through sea level rise, but scientists have long considered it more stable than its neighbor, West Antarctica. Now, new detailed NASA maps of ice velocity and elevation show that a group of glaciers spanning one-eighth of East Antarctica's coast have begun to lose ice over the past decade, hinting at widespread changes in the ocean. In recent years, researchers have warned that Totten Glacier, a behemoth that contains enough ... read more