by faster | Jun 28, 2017 | Blog
SOURCE: National Geographic DATE: June 28, 2017 SNIP: Seen from above, the Pine Island Ice Shelf is a slow-motion train wreck. Its buckled surface is scarred by thousands of large crevasses. Its edges are shredded by rifts a quarter mile across. In 2015 and 2016 a 225-square-mile chunk of it broke off the end and drifted away on the Amundsen Sea. The water there has warmed by more than a degree Fahrenheit over the past few decades, and the rate at which ice is melting and calving has quadrupled. On the Antarctic Peninsula, the warming has been far greater—nearly five degrees on average. That’s why a Delaware-size iceberg is poised to break off the Larsen C Ice Shelf and why smaller ice shelves on the peninsula have long since disintegrated entirely into the waters of the Weddell Sea. But around the Amundsen Sea, a thousand miles to the southwest on the Pacific coast of Antarctica, the glaciers are far larger and the stakes far higher. They affect the entire planet. “These are the fastest retreating glaciers on the face of the Earth,” says Eric Rignot, a glaciologist at the NASA Jet Propulsion Laboratory in Pasadena,...
by faster | Jun 28, 2017 | Blog
SOURCE: Climate Central DATE: June 28, 2017 SNIP: In the past two decades, the Greenland ice sheet has become the biggest single contributor to rising sea levels, mostly from melt across its vast surface. That surface melt is, in turn, driven mostly by an uptick in clear, sunny summer skies, not just rising air temperatures, a new study finds. While some of the water Greenland is flushing out to sea comes from warming ocean waters lapping away at the glaciers that drain the ice sheet, most is due to the melt across its surface during the summer. Stefan Hofer, a PhD candidate at the University of Bristol in England, and his colleagues looked into what the main drivers of that surface melt were, in particular the effect of cloud cover on melt. In satellite data spanning the past two decades, they saw a significant decrease in cloud cover over Greenland starting in the mid-90s, which would mean more sunlight was falling on the ice and driving melt. Climate models the team used suggest that every 1 percent reduction in cloud cover leads to another 27 gigatons of melt (the U.S. uses about 1.3 gigatons of water per day, according to data from NASA and the U.S. Geological Survey). That sensitivity to cloud cover was “pretty astounding,” William Colgan, a senior researcher with the Geological Survey of Denmark and Greenland who wasn’t involved in the study, said in an...
by faster | Jun 26, 2017 | Blog
SOURCE: New York Times DATE: June 26, 2017 SNIP: The excess carbon dioxide scorching the planet rose at the highest rate on record in 2015 and 2016. A slightly slower but still unusual rate of increase has continued into 2017. Scientists are concerned about the cause of the rapid rises because, in one of the most hopeful signs since the global climate crisis became widely understood in the 1980s, the amount of carbon dioxide that people are pumping into the air seems to have stabilized in recent years, at least judging from the data that countries compile on their own emissions. That raises a conundrum: If the amount of the gas that people are putting out has stopped rising, how can the amount that stays in the air be going up faster than ever? Does it mean the natural sponges that have been absorbing carbon dioxide are now...
by faster | Jun 26, 2017 | Blog
SOURCE: Washington Post DATE: June 26, 2017 SNIP: In at least the third such study published in the past year, scientists have confirmed seas are rising, and the rate of sea level rise is increasing as time passes — a sobering punchline for coastal communities that are only now beginning to prepare for a troubling future. What was a 2.2 millimeter per year rise in 1993 was a 3.3 millimeter rise in 2014, based on estimates of the mass changes of a number of key components of sea level rise, such as the melting of the Greenland and Antarctic ice sheets, the study in Nature Climate Change found. That’s the difference between 0.86 and 1.29 inches per decade — and the researchers suggest further sea level acceleration could be in...
by faster | Jun 26, 2017 | Blog
SOURCE: NASA JPL DATE: June 26, 2017 SNIP: A new NASA-funded study finds that lightning storms were the main driver of recent massive fire years in Alaska and northern Canada, and that these storms are likely to move farther north with climate warming, potentially altering northern landscapes. The study, led by Vrije Universiteit Amsterdam and the University of California, Irvine, examined the cause of the fires, which have been increasing in number in recent years. There was a record number of lightning-ignited fires in the Canadian Northwest Territories in 2014 and in Alaska in 2015. The team found increases of between two and five percent a year in the number of lightning-ignited fires since...
by faster | Jun 23, 2017 | Blog
SOURCE: Yale e360 DATE: June 23, 2017 SNIP: Seismic air guns commonly used in the search for undersea oil kill off far more zooplankton than once thought, according to a new study that raises questions about the effect of such seismic surveys on the health of ocean ecosystems. For the research, which was published in Nature Ecology and Evolution, scientists tested air gun signals in the ocean off Southern Tasmania and found a rise in mortality rate of 18 percent to between 40 and 60 percent. One reason was that the impacts were felt by the krill out to 1.2 kilometers, 100 times farther than the assumed range of 10...
