There’s nothing new about the fact that global warming is causing ice sheets to melt, resulting in rising sea levels. However a new study by an international team of scientists led by Edward Hanna of the University of Sheffield makes more accurate predictions about the process in Greenland and the Antarctic. The study, which was published in this month’s edition of Nature, found that Antarctic ice loss might only be half of what has been previously reported. But the team also found a major loss of mass from the Greenland Ice Sheet, which appears to be twice as large as the Antarctic contribution to global sea-level rise.
The study shows that the global sea level is currently rising at a rate just over an eight of an inch per year due to a combination of melting ice and the expansion of seawater caused by global warming. The team predicted that as the ice sheets in Greenland and the Antarctic continue to melt, the rate of sea level change will shoot upwards.
A more accurate assessment of ice sheet mass loss is possible due to improved computer models thanks to a better theoretical understanding of ice sheet physics and advances in measurement techniques that make use of radar, laser and satellite data. These improvements have come after the 2007 International Panel on Climate Change report made it clear that understanding of ice sheet behavior was still insufficient to accurately predict how the ice sheets of Greenland and the Antarctic will behave.
Though there have been improvements in computer modeling of ice sheets, it is proving more difficult, not less, to predict the behavior of ice sheets. More accurate data shows that the way ice sheets are responding to climate change is more complex than originally thought. And team member Slawek Tulaczyk, a professor of Earth and planetary sciences at UC Santa Cruz, warns that there are still significant gaps of knowledge about the way ice sheets behave, which could make it difficult to predict a sharp acceleration in ice sheet contribution to sea level rise.
Photos by Christine Zenino from Chicago, US (Greenland Ice SheetUploaded by russavia) [CC-BY-2.0], via Wikimedia Commons and by Christine Zenino from Chicago, US (Greenland IceUploaded by russavia) [CC-BY-2.0], via Wikimedia Commons