Last week a study was published in the Journal of Glaciology by a group of NASA researchers reporting that satellite data shows that, as a whole, Antarctica has been gaining—rather than losing—ice mass during the past two or more decades.
So was NASA and the Intergovernmental Panel on Climate Change (IPCC) wrong about Antarctica’s ice loss? Is the Antarctic ice growing?
The short answer is best summarized by the title of Andrew Freedman’s article on Mashable (which everyone should read): “No, NASA has not reversed itself on the dangerous melting of Antarctica.”
However, in less enlightened (or maybe honest) circles, the study’s finding is being reported as a massive turnabout of previous research showing the continent to be shedding ice at an increasing rate.
What these reports usually are missing are several critical points:
- This is one NASA study. Other NASA studies say different and research continues. It is a mistake to simply assume that this one is right and the others are wrong.
- Even if the study is correct, it doesn’t indicate that global climate change is not occurring. The increase in ice mass is the result of increased precipitation, which is the result of increased atmospheric water vapor, which is the result of increased global temperatures. (There are numerous other indicators that our climate is changing).
- The study’s lead author, Jay Zwally of NASA’s Goddard Space Flight Center in Maryland, agrees that the overall global rate of ice discharge into the oceans is increasing. “The good news is that Antarctica is not currently contributing to sea level rise, but is taking 0.23 millimeters per year away,but this is also bad news,” he added. “If the 0.27 millimeters per year of sea level rise attributed to Antarctica in the IPCC report is not really coming from Antarctica, there must be some other contribution to sea level rise that is not accounted for.”
- The lead author also notes that the state might be temporary. It could take only a few decades for the ice melt in Antarctica to outweigh the ice gains.
According to this study, the gains in ice from increased precipitation in the continent’s interior, particularly across the East Antarctic Ice Sheet, is enough to offset the melting occurring in the West Antarctic and Antarctic Peninsula.
However, the study does not contradict the troubling trends seen in Western Antarctica where there has been widespread loss of ice along the Bellingshausen and Amundsen Seas.
And what this study really illustrates is how difficult it is for scientists to measure small changes in ice. Fortunately, NASA is developing new tools—due to launch in 2018—that will help scientists more accurately measure long-term ice changes in Antarctica. The research on this continues, but is hardly a reason for not taking action on climate today.