25 February 2019
New Antarctic research “a big step forward” in predicting impacts of climate change
The Ross Ice Shelf holds the key to avoiding catastrophic sea-level rises as the planet warms – and new research will
help scientists monitor its future health.
An international team of researchers including New Zealand’s GNS Science took part in the ROSETTA-Ice project, mapping
the sea floor under the ice shelf.
Their findings are published in Nature Geoscience magazine today.
The Ross Ice Shelf occupies an area twice the size of New Zealand and is within the Ross Dependency, the region of
Antarctica over which New Zealand claims a right of sovereignty.
The shelf helps to slow the flow of Western Antarctica’s grounded sea ice into the ocean.
Most of the ice in West Antarctica sits on ground below sea level and is particularly vulnerable to increases in ocean
temperature.
If all of this marine-based ice were released into the ocean, global sea level would rise by at least 3.5 metres in the
coming centuries.
“Working with international partners allowed us to gather important data in an area where the floating ice shelf is
often more than 300 metres thick,” GNS Science marine geophysicist Fabio Caratori Tontini says.
“GNS Science contributed not just our expertise, but our dynamic gravimeter, which measures the earth’s gravitational
force from a moving aeroplane.
“This instrument makes measurements that allow us to model the shape of the sea floor under the ice – which is essential
for understanding how the ocean circulates and how the ice melts.”
“We could see that a previously unmapped geological boundary was making the seafloor on the East Antarctic side much
deeper than the West, and that affects the way the ocean water circulates under the ice shelf,” explained Kirsty Tinto,
the Lamont-Doherty Earth Observatory research scientist who led all three field expeditions and is lead author of the
study.
“This research will help scientists develop new ways of monitoring the health of Antarctic ice sheets,” GNS Science’s
Environment and Climate theme leader Richard Levy says.
“We can use this research to help determine where to place instruments to observe ocean currents that circulate beneath
the ice shelf.
“These observations can then guide computer models to predict how the Ross Ice Shelf and the West Antarctic Ice Sheet
will change as our climate warms.
“Some studies suggest that collapse of the ice sheets can be avoided if we reduce greenhouse gas emissions and keep
warming under 1.5 degrees centigrade above pre-industrial levels.
“This is the primary goal of New Zealand’s Zero Carbon Bill which is currently under consideration in Parliament.
“We need to know how Antarctica will respond to this relatively small amount of warming, and the ROSETTA team’s research
is a big step forward.”
The Nature Geoscience article can be accessed here: https://www.nature.com/articles/s41561-019-0370-2
The ROSETTA-Ice project partners include Lamont-Doherty Earth Observatory of Columbia University, Scripps Institution of
Oceanography at the University of California San Diego, Colorado College, Earth and Space Research and GNS Science.
Fieldwork was supported by the US Antarctic Program, the New York Air National Guard, the Ministry of Business,
Innovation and Employment and the NZ Antarctic Research Institute. ROSETTA-Ice is funded by the National Science
Foundation, the Moore Foundation and the Old York Foundation.
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