Credit: NASA’s Scientific Visualization Studio This visualization shows the Greenland geothermal heat flux map, the track of the Iceland hotspot through Greenland, and the plate tectonic motion of Greenland over the hotspot during the past 100 million years. The whole age of ice sheet waxing and waning in the Northern Hemisphere didn’t really get going until about five million years ago. Ten million years ago, there was actually very little ice present in Greenland. In fact, he says, the history of the Greenland ice sheet is probably more connected to atmospheric and ocean heat than it is to heat from the solid Earth. There are no active volcanoes in Greenland, nor are there any known mapped, dormant volcanoes under the Greenland ice sheet that were active during the Pliocene period of geological history that began more than 5.3 million years ago (volcanoes are considered active if they’ve erupted within the past 50,000 years). Credit: NASA/Michael Studingerīut volcanic activity isn’t responsible for the current staggering loss of Greenland’s ice sheet, says Ivins. The mountains here consist mostly of flood basalts formed during the opening of the North Atlantic Ocean millions of years ago. Since 2002, the U.S./German Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-On (GRACE-FO) satellite missions have recorded a rapid loss of ice mass from Greenland - at a rate of approximately 281 gigatonnes per year.Ī glacier between mountains on Greenland's Geikie Peninsula. Here's what I learned… Greenland Has a Long-Departed “Hot Spot” but Is Now Quiet I checked in with Ivins and Seroussi to get a deeper understanding of this question, which our readers frequently ask about. While the study may help explain why the ice sheet collapsed rapidly in an earlier era of rapid climate change and why it’s so unstable today, the researchers emphasized that the heat source isn't a new or increasing threat to the West Antarctic ice sheet, but rather has been going on over geologic timescales, and therefore represents a background contribution to the melting of the ice sheet. For example, a 2017 NASA-led study by geophysicists Erik Ivins and Helene Seroussi of NASA’s Jet Propulsion Laboratory added evidence to bolster a longstanding hypothesis that a heat source called a mantle plume lies deep below Antarctica's Marie Byrd Land, explaining some of the melting that creates lakes and rivers under the ice sheet.
In short, the answer is a definitive “no,” though recent studies have shed important new light on the matter. Marie Byrd Land is part of the bulging "elbow" in the left center of the image. Blue dots indicate lakes, lines show rivers. Click it to reveal your hidden games, which you can then play, install, or re-add to your library by unchecking the “Hide this game in my library” box under Set Categories.Illustration of flowing water under the Antarctic ice sheet. At the bottom of the list you’ll see a “Hidden” filter. Open your Steam Library once again, then click the Games link in the search box to bring up a drop-down menu. You know what I’m talking about, Steam users. Of course I hid that pesky Dota 2 Test listing lickity-split. The game is now banished from your Steam Library.īut what if one day you decide you want to take one of your outcasts for a whirl once again? Fear not: You can drag hidden games back into the light, though that process is also slightly less than intuitive.
In the pop-up menu that appears, check the box next to “Hide this game in my library,” then click OK. Simply open your Steam library, then right-click on the game you want to hide and select Set Categories. Click that button to hide a game from your Steam library.