The Antarctica ice controversy continues among researchers and scientists. Satellite data suggests that Antarctica ice is actually expanding. However, scientists claim the Antarctica ice expansion may be due to an error in the calibration of satellite processing data and changes in the sea ice record.
Antarctica ice controversy
Scientists have been monitoring Arctic sea ice using satellites since 1979. Yale Climate Connections, a climate news and information service and part of the Yale Center for Environmental Communication affirms that close to 580,000 square miles of Arctic ice has melted since initial observations. Additionally, since 1980 nearly 40 percent of the Arctic ice volume has vanished. On the other hand, according to National Snow & Ice Data Center (NSIDC) records, since September 2013 Antarctica ice is expanding.
This contrast between Yale’s recorded figures of ice melting and NSIDC’s data of ice expanding is perhaps due to the calibration of a new satellite sensor. Researcher of climate dynamics, Ian Eisenman, at the Scripps Institute of Oceanography at the University of California, San Diego claims a “minor update in 2007 that was not believed to have caused any notable difference in the trend caused this big jump."
Eisenman notes that prior to 2007, Arctic data was consistent; ice was neither shrinking nor expanding. Immediately after 2007, Arctic ice started showing signs of expansion. Eisenman initially implied what materializes to be Antarctica ice expansion is, in fact the result of adding a few more years to the sea ice record. However, he was not completely satisfied with this rationale.
Further investigation by Eisenman revealed changes in the way ice data was processed. This processing data used Bootstrap algorithm, an accepted algorithm for weaving together contrasting satellite measurements, developed by Dr. Josefino Comiso, Senior Research Scientist at NASA. These data processing changes took place in 1991 after replacing the satellite sensor. Eisenman suggests these alterations affected the data causing what appears to be ice expansion.
Antarctica sea ice, climate change, and weather
The Antarctica plays a significant role in a variety of ways concerning the global climate. For instance, Antarctica has circular winds that push freezing masses of air from the North Pole to the sea. Sea ice has an influence on how the oceans circulate, which greatly affects the climate. Additionally, sea ice reflects heat back into space. When there is a reduced amount of ice on Earth, less heat is reflected which cause faster warming. Furthermore, Antarctica’s wildlife, including the Arctic’s polar bears and Antarctica’s Weddell seals are reliant on sea ice to find food and shelter.
Is Antarctic ice expanding or vanishing?
The Intergovernmental Panel on Climate Change (IPCC) took note of the recent data on ice expansion in the Arctic and provided their fifth assessment report in 2013, a report they release every five or six years. Their report summarizes the science of climate change and the related socioeconomic and environmental and affects. This latest report by the IPCC confirms an increase of ice in Antarctica.
Moreover, Dr. Comiso believes the changes made in the Bootstrap algorithm initiated data bias; however, he suggests the data changes corrected problems and improved the algorithm. Furthermore, he contends that other groups have documented the Antarctica ice expansion and satellite data confirms the increase.
Dr. Comiso provided the following statement, "The sea ice extent showed basically no trend in the earlier period because the inter-annual changes in extent were more uniform and the errors were large. The trend in extent in the Antarctic sea ice has been shown to be positive in different publications. It is even more positive now than ever, and the Eisenman et al paper is providing a misinformation instead of a resolution."
Presently, Eisenman has been unable to pinpoint errors in the data, decisively. In the mean time, Eisenman said, "Whatever the root of this ends up being, I highly doubt it was anything egregious. We're working with nuanced datasets here, trying to make long-term measurements with multiple instruments, none of which are directly measuring what we want."
It appears that the Antarctica ice controversy will carry on a little longer.