A couple of weeks ago a new study came out from NASA indicating that the Antarctica land mass is gaining ice. This study by Zwally and colleagues, indicates ice accumulation in East Antarctic continent exceeds the loss of ice from the Western Antarctic Peninsula (WAP). This study is contradictory to many studies that have been published on this topic (Harig and Simons, 2015 or Shepherd et al., 2012, etc)! Previous studies have primarily indicated that Antarctica is currently losing glacial ice at a faster rate than it is gaining it. Loss of land ice has lead to increased rates of sea level rise. So if it is not coming from Antarctica, where is it coming from?! Well as I am sure you have guessed by this point, the paper in the Journal of Glaciology has sparked a bit of controversy in the scientific community. So how do we as readers, scientists and the general public know which study to believe?
My suggestion is to look at the facts not the media’s portrayal of the data and make your own informed decision. The best way to do this is to read the manuscript.
Mass gains of the Antarctic ice sheet exceed losses
Sometimes this can be hard. 1.You may not have time to read it. 2. You may not have access to the journal (which many probably don’t). 3. Sometimes the jargon is just too confusing to understand.
Here is my cliff notes version (from what I can understand):
Where is the data from: The data was collected via Satellite imagery. More specifically the NASA scientists used European Remote sensing Satellites 1 and 2 (ERS-1/-2) for the time period 1992– 2001 and satellite laser-altimeter measurements by the Ice, Cloud and land Elevation Satellite (ICESat) for times between 2003–08.
What type of data was collected: The scientists collected the elevation profiles across the continent.
How was the data analyzed: Using these elevation profiles, the amount of snow fall over antarctica and a lot of math and modeling they were able to derive the net mass change of the continent over the time period of the study.
What were the results: Antarctica is experiencing a net gain of ice at rates of approximately 82 gigatons per year (2003-2008). Thats a lot of ice!
This research is controversial because it not only raises questions about ice accumulation, it challenges what we currently understand about sea level rise. If the change in sea level (~3.2 millimeters per year) is not driven by ice loss in Antarctica then where is the water coming from? Another aspect of this work that has been targeted is the use of satellites to measure snow accumulations. Can a satellite accurately measure 1 to 2 centimeters of snow accumulation from space?
While I am no glacial scientist, my decision is to remain skeptical. For me personally, there are too many unanswered questions. How do we know the gain in ice truly offset the rapid melting of the WAP? What implications does this work have for the UN Conference of Climate Change in Paris at the end of the month? And more importantly, what does it mean for the penguins!!!? I guess we will all have to wait and see.