Greenland meltdown threatens key Atlantic Ocean current

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Sea ice swirls around Greenland in this NASA Earth Observatory photo.

‘If human activities are starting to impact this system, it is a worrying sign that the scale of human impacts on the climate system may be reaching a critical point’

Staff Report

Cold, fresh water from the Greenland Ice Sheet may disrupt a key ocean current in the North Atlantic, scientists said after updating estimates of the freshwater flux based on new satellite data. The study, published in the journal Nature Communications, warns that the changes could have as-yet uncertain implications for the global climate.

At issue is the Atlantic Meridional Overturning Circulation, which transports a large amount of heat into the North Atlantic where it is given up to the atmosphere and helps regulate the climate in Europe and North America. Continue reading

Climate: One more thing to worry about?

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Ongoing studies are detailing how melting ice sheets will affect sea level.

Eastern Greenland changes could threaten critical ocean current

By Bob Berwyn

The global climate agreement reached late last year in Paris isn’t going to stop the Greenland Ice Sheet from melting anytime soon. Even with an immediate halt to greenhouse gas emissions. there may be centuries more melting ahead, according to climate scientists.

And the meltdown could be more widespread than previously thought, according to National Snow and Ice Data Center scientist Lora Koenig, who gave an update on the latest research during this week’s Glen Gerberg Weather and Climate Summit in Breckenridge. Continue reading

Climate: Extreme Greenland Ice Sheet melting episodes change runoff regime

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Extreme melting on the surface of the Greenland ice sheet could change the sea level rise equation.

Study shows that 2012 melting created a dense ice cap

Staff Report

When warm temperatures in 2012 caused an extreme melting episode across much of the Greenland Ice Sheet, it may have fundamentally altered the way the near-surface snow layers absorb water, according to a new study published in Nature Climate Change.

The melting resulted in the formation of a thick layer of ice atop the previously porous surface. Subsequently, meltwater ran off the surface and to the ocean, with potential impacts on sea level, according to York University Professor William Colgan. Continue reading

How fast are Greenland’s glaciers melting?

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Greenland’s glaciers are melting fast, threatening more sea level rise. @bberwyn photo.

Meltdown?

Staff Report

If world leaders need one more sign that they must reach a decisive climate agreement this week in Paris, it might be a new study showing that Greenland’s glaciers are retreating at least twice as fast as any other time in the past 9,500 years.

Melting ice from the Greenland Ice Sheet threatens to flood millions of people in low-lying coastal areas in the next few decades, and the study shows just how sensitive the glaciers are to warming temperatures. Continue reading

Are some of Greenland’s glaciers slowing down?

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All eyes on the Greenland Ice Sheet, as global warming speeds up. @bberwyn photo.

New research shows looks specifically at glaciers ending on land

Staff Report

Parts of the Greenland Ice Sheet may actually be slowing down, rather than speeding up, in response to decades of climate change, but that doesn’t mean it’s time to stop worrying about sea level rise.

In a new study, glaciologists measuring ice movement on the southwest portion of the Greenland Ice Sheet found that glaciers terminating on land have slowed by an average of 12 percent across 84 percent of the study area between 2007 and 2014, compared to the years between 1985 and 1994. The study looked specifically at ice sheets terminating on land, not those flowing into the ocean.

The scientists said their findings appear to contradict conventional wisdom. Many recent studies have suggested that more surface melting will speed up ice sheet movement. The amount of meltwater draining from the ice sheet in four out of the five years between 2007 and 2012 has been the most substantial of the last 50 years. Continue reading

Climate: Does solar activity drive North Atlantic currents?

A new study found that Greenland temperatures fell from the 1970s through the early 1990s while temperatures across much of the rest of the Northern Hemisphere rose. This map shows the average difference in surface temperatures between 1920-1940 and 1975-1995. Grey areas indicate regions where not enough data was available to calculate long-term temperature changes. Credit: Takuro Kobashi

Greenland temperatures fell from the 1970s through the early 1990s while temperatures across much of the rest of the Northern Hemisphere rose, and solar activity may be an important factor.
Credit: Takuro Kobashi

Low solar activity could speed Greenland Ice Sheet melting in coming years

Staff Report

FRISCO — Solar activity could be an important factor in determining how fast the Greenland Ice Sheet melts, scientists concluded in a new study after analyzing ice cores and historical temperature records.

Based on their analysis, the researchers found that High solar activity starting in the 1950s and continuing through the 1980s played a role in slowing down ocean circulation between the South Atlantic and the North Atlantic oceans. Continue reading

Study explores Greenland Ice Sheet plumbing

A meltwater lake on the surface of the Greenland Ice Sheet. Now researchers are tracking where that water goes, and how it may affect ice sheet movement. Photo courtesy Thomas Nylen, NSF.

A meltwater lake on the surface of the Greenland Ice Sheet. Now researchers are tracking where that water goes, and how it may affect ice sheet movement. Photo courtesy Thomas Nylen, National Science Foundation.

Surface meltwater feeds subglacial lakes

Staff Report

FRISCO — Scientists who recently took a close look at the “plumbing” of the Greenland Ice Sheet say that meltwater from the surface is building up lakes beneath the ice and transporting heat to the bottom of the ice sheet.

The research, led by Cornell University Earth and Atmospheric Sciences researcher Michael Willis, includes groundbreaking findings that give new information about atmospheric warming and its affect on the critical zone at the base of the ice. The warmth provided by the water could make the ice sheet move faster and alter how it responds to the changing climate. The research is detailed in a new paper published online by the journal Nature on Jan. 21. Continue reading

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