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Watching the Ice Melt

UC Irvine's professor Eric Rignot studies the problem of Antarctic ice melt.

Antarctica is melting. That point few will dispute. Figuring out how and why and what it means for the distant continent and sea levels everywhere are the finer points that have roped scientists into an unsavory political rhubarb not seen since the days of Galileo or the Scopes Monkey Trial. But the work goes on for those studying the problem, like professor Eric Rignot of UC Irvine. And important facts continue to be found.

Rignot and UCI colleagues Jeremie Mouginot and Bernd Scheuchl, as well as Stanley Jacobs of Columbia University, just completed the first comprehensive survey of the Antarctic ice shelves. They found that the vast permanent floating sheets of ice that blanket the outer edges of the continent are melting from below, and at a much faster rate than previously thought. Rignot’s data suggest that ocean temperatures play a much larger role in the ice shrinkage, rather than chunks simply breaking off as icebergs.

Besides being a professor, the transplanted Frenchman is also a researcher for NASA’s Jet Propulsion Laboratory in Pasadena and has published multiple papers on Antarctic and Greenlandic ice shelves. Rignot says the satellite photographic evidence was not as clear as originally thought because it was pointing to the ice melting from below – a major, yet hard to immediately discern thinning of the ice – before it broke off.

“The traditional view on the Antarctic ice sheet is that most of the ice released into the ocean breaks up as icebergs,” Rignot says. “We find that in reality most of the ice melts in contact with the ocean waters and then breaks up into icebergs.”

It’s that important difference that will surely stir some debate. However, Rignot and his colleagues found a similar effect, something Rignot refers to as “partitioning,” happening at the other end of the planet as well. “Estimating the rate of melt of these glaciers is an active area of research, with many challenges. But it is very likely that the same [thing is happening] in Greenland.”

The study used the combined observations from different sensors over a nearly six-year period, and the data collected helps researchers continue to evaluate ice-ocean models, placing more importance on the ocean’s role in dictating the growth and melt of ice sheets.

But no matter how methodical and careful studies like these can be, they nevertheless become fodder for the current political debate over climate change, something Rignot is acutely aware of.

“Climate change will remain a hot topic for the coming century. Not so much the reality of it, which has been well established, and its consequences, which are far more dramatic than many of us are willing to realize,” Rignot says. “It is, what are we going to do about this?”

“The reality of climate change puts more pressure on us to make major advances sooner rather than later. In the big picture, however, changes in precipitation, water supply and biodiversity are more immediate threats to the world than rising sea level.”

Rignot believes the reason NASA is studying climate change is a simple one. Its goal is “to study life here and there,” he says. And the agency’s technology is key to better observing “a very important planet, the one we are living in.”

Rignot seems to thrive off the JPL environment as well. He says it is not the stuffy place people might think, but “a very dynamic and unique place and a culture of superior achievement that drives your energy. JPLers are passionate about what they do.”

He remains optimistic that scientific facts will end the debate about climate change, but knows it’s a long process because the implications are complicated and profound.

“It is slow because there is a lot of misinformation. For instance, the idea that scientists debate whether it is real or not, and there is an oil industry that cannot change overnight. It involves major societal changes, major changes in the way we use and produce energy and natural resources, and in our political guidance,” Rignot says. “We are still in the stage of slow awakening, burning fast and not acting.”

Learn More  
nasa.gov :: ess.uci.edu/researchgrp/erignot


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