5 November 2015, Washington Post, A controversial NASA study says Antarctica is gaining ice. Here’s why you should be skeptical. Late last week, a study published by NASA scientists in the Journal of Glaciology made the surprising claim that the gigantic continent of Antarctica is actually gaining ice, rather than losing it, to the tune of 82 gigatons (or billion metric tons) per year from 2003 to 2008. The study has drawn massive amounts of media attention — and no wonder. It contradicts numerous prior scientific claims, including a 2012 study in Science by a small army of polar scientists, a study from earlier this year in Earth and Planetary Science Letters (which found 92 gigatons of net losses per year) and this 2014 study in Geophysical Research Letters (160 gigatons of net losses per year). It also contradicts assertions by the leading consensus body of climate science, the U.N.’s Intergovernmental Panel on Climate Change, which stated in 2013 that Antarctica is “losing mass” and that this process is accelerating. That statement was itself based on multiple studies showing Antarctic ice loss. Not only does the new research fly in the face of all of this — if true, it also raises serious questions about our current understanding of sea level rise. If Antarctica is actually gaining ice, that means that a significant percentage of the current rise of the seas, estimated at roughly 3.22 millimeters per year by NASA itself, must be coming from elsewhere. (It takes 360 gigatons of ice to raise seas by 1 millimeter). No wonder, then, that a number of researchers have been quoted expressing skepticism about the new research, even as climate change doubters have had a field day — adding the study to an argumentative arsenal that previously included misleading claims about growing Antarctic sea ice. Read More here
Category Archives: Antarctica
30 October 2015, Daily Science, Mass gains of Antarctic Ice Sheet greater than losses. A new study says that an increase in Antarctic snow accumulation that began 10,000 years ago is currently adding enough ice to the continent to outweigh the increased losses from its thinning glaciers. A new NASA study says that an increase in Antarctic snow accumulation that began 10,000 years ago is currently adding enough ice to the continent to outweigh the increased losses from its thinning glaciers. The research challenges the conclusions of other studies, including the Intergovernmental Panel on Climate Change’s (IPCC) 2013 report, which says that Antarctica is overall losing land ice. According to the new analysis of satellite data, the Antarctic ice sheet showed a net gain of 112 billion tons of ice a year from 1992 to 2001. That net gain slowed to 82 billion tons of ice per year between 2003 and 2008. “We’re essentially in agreement with other studies that show an increase in ice discharge in the Antarctic Peninsula and the Thwaites and Pine Island region of West Antarctica,” said Jay Zwally, a glaciologist with NASA Goddard Space Flight Center in Greenbelt, Maryland, and lead author of the study, which was published on Oct. 30 in the Journal of Glaciology. “Our main disagreement is for East Antarctica and the interior of West Antarctica — there, we see an ice gain that exceeds the losses in the other areas.” Zwally added that his team “measured small height changes over large areas, as well as the large changes observed over smaller areas.” Read More here
26 October 2015, Washington Post, Scientists confirm that East Antarctica’s biggest glacier is melting from below. Earlier this year, we learned some worrisome climate news. Although Antarctic scientists have been most concerned about loss of ice in the western part of Antarctica, a study in Nature Geoscience suggested a vulnerability in the much larger ice sheet of East Antarctica, as well. East Antarctica’s enormous Totten Glacier, you see, has a key similarity with the glaciers of West Antarctica — namely, it is rooted deep below sea level. This means that it is potentially exposed to warm ocean waters, and the study in March uncovered a deep and 5-kilometer wide subsea valley beneath the glacier’s oceanfront ice shelf that, the authors said, could be a route for warm offshore water to reach its base. This might explain why the glacier has been observed to be thinning and lowering, or losing elevation, over time, they noted. Located along East Antarctica’s Sabrina Coast, Totten glacier is the ice sheet’s largest. It holds back 3.9 meters of potential sea level rise, or over 12 feet, and connects with the very deep and vast Aurora Subglacial Basin, which is also rooted well below sea level. So the results were treated as being of enormous consequence. But they’re not the end of the story, as there is vastly more to learn about Totten glacier. A new study out in Geophysical Research Letters reaffirms some of these core concerns about Totten’s melt — while also appearing to partly alleviate others. Read More here
22 October 2015, Carbon Brief, Five charts that show how Arctic and Antarctic sea ice is faring in 2015. At this time of year, there are big differences in what’s going on with sea ice at either end of the world. September saw the Arctic hit its fourth lowest summer minimum on record, while over in Antarctica, the winter maximum finished just above average, ending a streak of record highs in the last three years. Carbon Brief takes a look at what’s happened this year and how it fits in with long term trends. Summer minimum Scientists have been using satellites to measure sea ice extent at the north and south poles since the late 1970s. They take measurements daily, and record the annual minimum and maximum as an indicator of how the poles are changing. In the Arctic, the end of the summer marks the point when sea ice is at its smallest extent, before it freezes up again as temperatures fall. Scientists keep a close eye around the time the low is normally reached – usually mid september – then look for signs of ice accumulating again in order to pinpoint exactly when the summer minimum is reached. According to the National Snow and Ice Data Center (NSIDC) in the US, the summer low occurred this year on 11 September. But because sea ice can throw in a late dip or surge, the NSIDC waited until 6 October before finally confirming this summer’s minimum of 4.41m square kilometers (sq km) – the fourth lowest on record. So how did the rest of the season shape up before this point? Read More here