A recent NASA study may be giving people the wrong impression about climate change - here's why.
We reported recently that NASA made a rather peculiar announcement. A new study shows that the Antarctic Ice Sheet has been adding more ice than has melted in previous years. According to a report from Christian Science Monitor, the study flies in the face of some of the most reputable sources on the dynamics of polar ice in Antarctica, including the Intergovernmental Panel on Climate Change.
The study, which was published in the Journal of Glaciology this Friday, reveals that Antarctica has added 112 billion tons of ice each year from 1992 to 2001. This finding suggests an obvious explanation – it’s nowhere near warm enough at the South Pole for ice to be melting at an alarming rate. But this couldn’t be further from the truth.
Between 2003 and 2008, the gains to the Antarctic Ice Sheet slowed down to a rate of about 82 billion tons of ice each year. The study used complex satellite imaging technology to measure the thickness of the ice, but given the vast area to cover on the southernmost continent, researchers say that they could benefit from more accurate equipment.
Despite the conclusion that ice cover in Antarctica has been growing in recent decades, scientists aren’t convinced this trend will last. It is important to consider the geography of the continent when interpreting the data; the majority of ice melt on the continent occurs in the coastal regions on the West Antarctic Ice Sheet. As ocean water continues to warm glaciers from below, massive chunks of ice break off or “calve” into the sea.
Interestingly enough, the study found that the gains to ice cover in Antarctica result in a negative contribution to sea level rise. That is to say, Antarctica’s growing ice sheet actually prevents 0.23 millimeters of sea level rise annually. This is in direct conflict with the IPCC’s calculation that Antarctica contributed 0.27 millimeters of sea level rise each year. According to the study’s author, NASA glaciologist Jay Zwally, this means that a massive error was made in calculating the sources of sea level rise somewhere.
Given the massive challenge of measuring the ice cover in Antarctica using airplanes and satellites, the scientists at NASA are certainly not asserting that climate change has ceased to be a problem. Dr. Zwally acknowledges that other studies examining the localized discharge of ice into the ocean from certain regions in the West Antarctic Ice Sheet are accurate, and the gains to the ice cover are largely the result of increasing ice mass in the center of the continent, and not near the warming ocean.
Gains in elevation in the Eastern half of Antarctica are largely attributed to snowfall, which contributes to the thickening of the ice cover. There is little doubt that climate change has ceased to affect the Antarctic ice, but it appears to be doing so in a number of different ways. Future studies will attempt to gain more accurate readings of the dynamics of the ice in Antarctica, but for now researchers have to put the pieces together for themselves.
A press release outlining the NASA study’s findings can be found here.