Patagonia ice sheets are thicker than previously thought, according to a study

After conducting a seven-year comprehensive survey in Patagonia, glaciologists at the University of California, Irvine and partner institutions in Argentina and Chile have concluded that the ice sheets in this vast region of South America are considerably larger than expected .

Using a combination of ground-based observations and airborne gravimetric and radar sounding methods, scientists created the most comprehensive ice-density map of the region and found that some glaciers were as thick as 1 600 meters. Their findings were published today in the journal American Geophysical Union Geophysical Research Letters.

"We did not think that the ice fields on the Patagonian plateau could be so important," said Eric Rignot, co-author, professor at Donald Bren and chairman of the UCI's Earth System Science Committee. "Thanks to this multinational research project, we have found that the northern and southern parts of Patagonia retain significantly more ice than expected, about 40 times the volume of ice in the European Alps."

Patagonia is home to the largest ice fields in the southern hemisphere, outside of Antarctica, and its glaciers are among the fastest in the world. Radar altimetry and optical imaging surface elevation observations have shown that most ice patches in the region have rapidly cleared over the last four decades. The contribution of their melt to the rise in the global level of the sea has increased at an accelerated rate during this period.

Dr. Gabriela Lenzano, co-author of the study, researcher at the National Council of Scientific and Technical Research of Argentina, said that these results "will help the scientific community to better explain the interactions and consequences of the dynamics of the ice cap and climate on this cold environment – and their impact on the environment. " downstream communities and ecosystems ".

With a more accurate understanding of the size and shape of glaciers in this highly protected area – which is largely contained in one of the largest national park systems in the world – researchers and planners will be able to to more accurately model the effects of global warming and to plan for potential disturbances to the freshwater resources that serve its inhabitants.

"That's why it's a priority to have accurate maps of the thickness of the ice," said Romain Millan, principal author of the thesis, who studied earth system science for most of this research project. . He is now a postdoctoral fellow at the Institute of Environmental Protection. Geosciences in Grenoble, France. "It is fundamental to correctly define the contours and the depths of the glacial valleys, otherwise the glacier retreat simulations will always be wrong."

The difficulty in quantifying the rise and thickness of the bed has limited the ability of scientists to predict the region's potential contribution to sea level rise; modeling of glacier dynamics in response to climate change; study impacts on freshwater resources; or prepare for dangers such as floods caused by the explosion of a lake, which occurs when a dam containing a glacial lake is failing.

Past attempts to estimate the total weight of the ice were unsuccessful, as traditional drilling techniques were limited to the shallower sections of the pack ice. Another obstacle is the temperate nature of Patagonian ice. The frozen water in the glaciers is close to its melting point from top to bottom; the higher water content makes this type of ice more difficult to measure with a radar.

To meet these challenges, scientists flew over large areas of land in helicopters and fixed-wing aircraft equipped with gravimeters, devices capable of determining ice volume by reading changes in the gravitational field of the aircraft. Earth. The addition of data collected by glaciologists from the Chile Science Center, which had mapped the thickness of the ice using low-frequency airborne radar probes since 2002, has allowed to create a more complete description of the conditions of the region.

"This research has been improved and successfully completed thanks to our collaboration with the UCI Rignot Group and our Argentinean colleagues, with whom we have worked on both sides of the southern ice floe of Patagonia, without taking into account the political border that divides the region, "said co-author Andrés Rivera of the Chilean center.