Earth’s Ice Is Melting Much Faster Than Forecast.

Earth’s Ice Is Melting Much Faster Than Forecast.

SOURCE: Garn Press DATE: February 5, 2018 SNIP: The key question, as I see it, is how to project what the sea level will soon be due to ice sheet melting. But this is confounded by us not really knowing what to expect. We keep being surprised by nature being more sensitive and complex. As the science develops, we see more interconnection, where multiplying feedbacks produce surprisingly fast responses. Will there be some saving self-regulation of human-induced climate warming and its melting land ice consequences? The enormous increase of heat in our oceans, from past decades of enhanced greenhouse effect, negates any hope that negative feedbacks or even solar output will prevent a much warmer world. The few negative feedbacks we have found for ice — like more snow as a result of a warming climate, more reflective frost, more efficient sub-glacial water transmission — are clearly being outdone. And at the global scale, despite some negative feedbacks like more clouds, clearly we are not seeing net cooling. Feedbacks, whether positive or negative, only do their thing after the initial effect. Negative feedbacks don’t reverse the perturbation. Seemingly the biggest issue with abrupt sea level rise comes from the now unstoppable loss of key sectors of west Antarctic ice and the discovery of more marine instability than we thought elsewhere. Like glaciers thinning rapidly in east Antarctica. Or in Greenland where improved bedrock maps reveal a marine connection an average of 40 kilometers further inland than previously thought. Or like how new fjord underwater mapping reveals greater fjord depths, increasing the odds that deep warm ocean water can communicate...
Algae Growth Reduces Reflectivity, Enhances Greenland Ice Sheet Melting

Algae Growth Reduces Reflectivity, Enhances Greenland Ice Sheet Melting

SOURCE: American Geophysical Union (AGU) DATE: December 20, 2017 SNIP: New research shows algae growing on the Greenland ice sheet, the Earth’s second-largest ice sheet, significantly reduce the surface reflectivity of the ice sheet’s bare ice area and contribute more to its melting than dust or black carbon. The new findings could influence scientists’ understanding of ice sheet melting and projections of future sea level rise, according to the study’s authors. The new study quantitatively assessed how surface ice algae contribute to darkening of the ice sheet, and found the algae reduce the ice sheet’s albedo significantly more than non-algal materials, like mineral particles and black carbon. Algal darkening is responsible for 5 percent to 10 percent of the total ice sheet melt each summer, according to the new research published in Geophysical Research Letters, a journal of the American Geophysical Union. Absorption of sunlight is responsible for most of the ice melt in Greenland, according to Jason Box, a climatologist at The Geological Survey of Denmark and Greenland and the other lead author of the new study. Microbes such as algal cells colonize the ice and can accumulate over time given enough sunlight, water and nutrients. Surface ice algae produce dark pigments to protect themselves from high intensity radiation, further darkening the sheet surface, Marek Stibal, a cryosphere ecologist at Charles University in Prague, Czech Republic and one of the lead authors of the new study, said. The new study didn’t estimate how much more ice could melt in the future due to algal darkening. But the results can lay the groundwork to devise more accurate projections of...
Greenland’s ice sheet is driving global sea level rise. One section is melting 80% faster.

Greenland’s ice sheet is driving global sea level rise. One section is melting 80% faster.

SOURCE: Vox DATE: December 14, 2017 SNIP: Average temperatures around the world may be slowly ticking upward, but their effects on the environment can be sharp and quick. Earlier this week, we learned that Arctic sea ice extent is declining at its fastest rate in 1,500 years. On Wednesday, scientists reported that in 2003, the ice sheet on Greenland suddenly began melting at a much faster rate. Greenland’s ice is hugely important for the planet. The sheet of ice that covers 660,000 square miles is more than a mile thick and has a volume of 684,000 cubic miles. If it all melts, it would raise global sea levels by 25 feet. On Thursday, scientists published a new map of the land mass beneath Greenland’s ice, showing that the ice is deeper than previously thought, so losing it all would lead to an additional 2.7 inches of sea level rise above past estimates. In a paper published Wednesday in the journal Science Advances, scientists reported that in one catchment in Southwestern Greenland, the melt rate surged 80 percent between 2003 and 2014 compared to the 26-year period beforehand, hinting at changes in the overall melt rate of the ice...
New Maps Show How Greenland’s Ice Sheet Is Melting from the Bottom Up

New Maps Show How Greenland’s Ice Sheet Is Melting from the Bottom Up

SOURCE: Scientific American DATE: November 6, 2017 SNIP: Significantly more ice in Greenland’s glaciers may be exposed to warming ocean waters than previously thought, new research suggests. Indeed, more than half the ice sheet may be subject to the melting influence of the sea. These are the latest conclusions of a detailed mapping project exploring the topography of the seafloor and bedrock around and beneath Greenland’s glaciers. Published in their final form last week in the journal Geophysical Research Letters, the maps draw on a variety of data sources, including satellite radar and aerial imagery, as well as special sonar data collected on ship expeditions to the front of the ice sheet. Included in the new paper are some of the most detailed data yet on the depths of the canyons and fjords scarring the Greenland coast, which carry water in from the sea to lap against the ice. The results suggest that the western and northern regions of Greenland are most exposed to the influence of ocean water. Out of 139 ocean-touching glaciers the team identified, they also found that 67 rest in waters 200 meters (about 650 feet) or more below sea level, where warm water is typically found—at least twice as many as previously...
Pakistan’s glaciers face new threat: Highway’s black carbon

Pakistan’s glaciers face new threat: Highway’s black carbon

SOURCE: Reuters DATE: November 3, 2017 SNIP: The Karakoram Highway has been around since 1982, but the Chinese-funded upgrade – which opened in 2015 – has turned a once treacherous track into a 15-foot-wide paved road. A series of tunnels, cut through the mountains, have reduced the driving time to the Khunjerab Pass from Gilgit, the capital of Gilgit-Balistan region, from eight hours to four hours. Now trucks are pouring over the border, laden with Chinese goods and equipment headed to Sost, the first border town on the Pakistani side, and then further down the 1,300-kilometre (800-mile) highway toward the port of Gwadar. The highway upgrade, part of the ambitious China Pakistan Economic Corridor, “has two impacts – one is positive and the other negative,” said Qamar-uz-Zaman Chaudhry, the author of Pakistan’s national climate change policy. “It will bring in much-needed infrastructure. But the carbon emissions and the soot going into the atmosphere will definitely increase – and our mountain glaciers will melt. We need to do a comprehensive study on the impacts and then develop a strategy,” he said. [D]ata gathered over the last 50 years shows that all but around 120 of the glaciers are showing signs of melting, meteorological officials said. Warming temperatures are to blame for much of the melting but so-called “black carbon” – black soot released from diesel vehicle exhaust, factories, open fires and cookstoves – also is to blame, experts say. The highway upgrade is just part a huge Chinese investment push into infrastructure in Pakistan – including a series of new coal-fired power plants – under the China Pakistan Economic Corridor...