What Is Eating Away at the Greenland Ice Sheet?

What Is Eating Away at the Greenland Ice Sheet?

SOURCE: Inside Climate News DATE: April 19, 2018 SNIP: [T]emperatures are rising in the Arctic at about twice the global average. That causes melting around the edges of the ice sheet each year and reaches across more of the surface during summer heat waves. In areas near the edge of the ice sheet, things get even more interesting: a carpet of microbes and algae mixed with dust and soot, a short-lived climate pollutant, is darkening the ice sheet, absorbing the sun’s rays and accelerating the melting of the ice. New research shows this dark zone is growing. The new research, published in the journal Nature Communications, describes a geological feedback loop on the ice that’s expanding the dark zone: Warming melts the western edge of the ice sheet, releasing mineral dust from rock crushed by the ice sheet thousands of years ago. That dust blows to the surface of the ice, nurturing the microbes and algae living there. Those organisms produce colored pigments as sunscreen, which contribute to the darkening of the surface, reducing reflectivity and increasing melting. “Just the little bit of extra heat from a tiny soot particle can start transforming feathery and highly reflective snow crystals into darker, rounded grains that absorb more heat,” said climate researcher Jason...
‘Extreme’ Iceberg Seasons Threaten Oil Rigs and Shipping as the Arctic Warms

‘Extreme’ Iceberg Seasons Threaten Oil Rigs and Shipping as the Arctic Warms

SOURCE: Inside Climate News DATE: March 28, 2018 SNIP: As the planet warms, giant icebergs and sea ice that once would have remained trapped in the frozen Arctic are moving southward faster and more frequently, menacing shipping and oil and gas drilling operations. In the North Atlantic, scientists say the number of icebergs spotted south of 48 degrees latitude—where they start to get into more shipping lanes—is up again this year, following a series of extreme iceberg seasons. That ice can pose serious risks to ships and offshore oil and gas rigs. Last year, strong storms sent a swarm of icebergs surging into the oil and gas drilling field at the Grand Banks off Newfoundland, marking the fourth extreme iceberg season in a row, according to International Ice Patrol Commander Gabrielle McGrath. “There were so many in the area that we couldn’t count them all. Our models couldn’t keep up with how quickly they were moving to the south,” she said. Increased ice mobility is a sign that the Arctic climate system is likely to change in big increments in the next few decades, said University of Manitoba ice researcher Dave Babb, one of scientists who tested the sea ice off Newfoundland last year. The Arctic Ocean along the northern coast of Alaska is remaining unfrozen for more than two months longer than just 30 years ago, and there’s evidence that storms are getting stronger over the open water, and whipping up bigger waves. The extreme conditions would make cleaning up an oil spill nearly...
New Maps Highlight Antarctica’s Flowing Ice

New Maps Highlight Antarctica’s Flowing Ice

SOURCE: EOS DATE: March 12, 2018 SNIP: From bold purple to brilliant yellow-orange bursts, the map above pinpoints regions along coastal Antarctica that have recently experienced moderate to severe ice loss. The map’s surface ice velocities, measured in meters per year, come from Landsat 7 and 8 data averaged over 2013–2015. As this map shows, ice loss in western Antarctica is faster and more extensive than in the east, particularly in the Ronne (upper) and Ross (lower) ice shelves. The data underlying this map that depicts recent Antarctic ice flow are from a 13 February study published in The Cryosphere. Not only is ice loss in western Antarctica already much higher than on eastern shores, but it’s also accelerating, according to the research team behind the map and paper. By comparing the most recently available Landsat data with earlier estimates of ice velocity from 2008, the team could determine where ice loss has sped up or remained steady across nearly the entire Antarctic Ice Sheet. [T]he speed of ice loss [in the Marguerite Bay area] increased from about 2,600 to 3,000 meters per year in some locations. That’s a jump of roughly 400 meters per year...
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...