Friday 30 October 2015

Greenland's ice becoming like Swiss cheese

Greenland's ice becoming 'Swiss cheese' due to global warming, New York Times says

Scientists are studying the flow of water from rivers like these that criss-cross Greenland's ice sheet, trying to determine how much water moves through sinkholes to beneath the sheet and flow into the nearby ocean, and how much refreezes before then. Photo acquired July 19, 2015. (Maria-Jose Vinas)

27 October, 2015

Scientists studying the surface of the Greenland ice sheet have found that global warming is creating new rivers that disappear into sinkholes called "moulins" that drain through ice tunnels into the ocean, their melted water adding to the world's rising seas, the New York Times reported Tuesday (Oct. 27).

The ice sheet has become porous, "like Swiss cheese," Laurence Smith, head of the University of California, Los Angeles, geography department, and leader of the Greenland science team, told the reporters.

The Greenland research is part of the effort of thousands of scientists supported by close to $1 billion in federal research dollars a year aimed at determining the speed of rising sea levels in the 21st Century and other problems caused by climate change.

Congress directs that money through the National Science Foundation, NASA and the National Oceanic and Atmospheric Administration, the New York Times story said.

"But the research is under increasing fire by some Republican leaders in Congress, who deny or question the scientific consensus that human activities contribute to climate change," said the story by reporters Coral Davenport, Josh Haner, Larry Buchanan and Derek Watkins

Those critics include Rep. Lamar Smith, R-Texas, chairman of the House science committee, who has tried to cut $300 million from NASA's earth science budget and is raising questions about 50 National Science Foundation Grants.

The Times' four-reporter team tracked the efforts of one team of scientists whose funding could be targeted by such critics.

The researchers needed ground-truth from a trip to one of the large rivers and sinkholes on the ice sheet to help direct computer model estimates of the amount of water flowing into the ocean from thousands of similar rivers, the story said, with the information they glean being used to test broader world climate model predictions for sea rise.

Smith said the experiments might actually find that the meltwater is refreezing within the thick ice layer, which could mean the sheet actually is melting more slowly than predicted.

The New York Times piece

Greenland ice sheet melts: Planetary Emergency Issued by NASA

SAN FRANCISCO — Greenland's disappearing ice shifted gears in the past decade, switching from shrinking glaciers to surface melting, researchers reported here last week at the American Geophysical Union's annual meeting.

Instead of losing ice where massive glaciers meet the sea, Greenland now sends meltwater rushing into the ocean via a vast network of lakes and rivers, according to several studies. The results do not mean that glaciers have stopped their speedy flow, only that surface melting now exerts a more powerful influence on ice loss, researchers said.

"We no longer see giant icebergs calving" from glaciers, releasing ice into the sea, said Lora Koenig, a glaciologist at the National Snow and Ice Data Center, who led one of the new studies. "The majority of water is coming from surface melt.

Greenland, one of the largest ice sheets in the world, is melting. In fact, it is melting ahead of schedule as the world warms. Scientists are working hard to deepen their understanding of this ice sheet’s behavior so that we can predict how fast and how much of the ice sheet will melt in the coming decades and centuries.

It might seem obvious that in a warming world, the Greenland ice sheet will melt. But, what seems obvious and simple can be more complex when investigated more deeply. With respect to Greenland, it is expected that warmer temperatures increase melting but warmer temperatures can also mean more snowfall, as there is more moisture in warm air which can then fall as snow. So, it has been a question of which of these two competing processes would win out. Would Greenland get smaller because of melting or would it grow as more snow fell?

Over the past few years, the verdict has become clear. The Greenland ice sheet is losing mass at an increasing rate. In fact, Greenland currently contributes twice as much as the Antarctic to rising sea levels.

A new study, just published in Nature Geoscience, makes an important new contribution to our understanding of the forces at play in Greenland. Dr Samuel Doyle and an international team captured the wide-scale effects of an unusual week of warm, wet weather in late August and early September, 2011. They found that weather cyclonic led to extreme surface runoff – a combination of ice melt and rain – that overwhelmed the ice sheet’s basal drainage system. This drive a marked increase in ice flow across the entire western sector of the ice sheet that extended 140 km into the ice sheet’s interior.

The cyclonic weather system delivered heat and rain to the western edge of the Greenland ice sheet and under these warm, wet, cloudy conditions the way that the ice sheet receives energy for melt is very different to that under the more typical clear sky conditions. As we all know from a cloudy day, clouds block a certain amount of sunshine, but under certain conditions they can absorb the outgoing longwave radiation and re-radiate it back to the surface. This is why a cloudy night is often warmer than when the sky is clear. The same thing happens on the ice sheet.

In fact during the August 2011 weather event, melt continued throughout both day and night creating exceptionally high daily melt totals for this time of year. Moisture in the atmosphere also reduces the rate at which the air cools as it rises over the ice sheet, allowing warm temperatures and therefore melt and rain to attain abnormally high elevations. The heat released by condensation and by rain refreezing in the snowpack enhanced melt even further.

Even given these factors, the water runoff from melt and rain did not exceed mid-summer peak values when ice flow was relatively slow. This is because the ice sheet’s drainage system continually adapts to melt inputs: in mid-summer an efficient drainage system forms and the ice sheet can easily accommodate high water inputs. This isn’t the case in late summer though, as the drainage system rapidly freezes shut when air temperatures fall below zero.

The influence of such intense rainfall events has not, until now, been considered in assessments of the melt and flow response of any ice sheet. This is an important omission because cyclonic conditions are predicted to increase in the future, therefore likely playing an increasing role in driving ice mass loss from the Greenland ice sheet.

Since the 1980s when rainfall measurements began in the west Greenland town of Kangerlussuaq, the focus of the study, the proportion of precipitation now falling as rainfall rather than snow has both increased and extended into the late summer and autumn in line with increased circulation and moisture availability within a warmer, more energetic atmosphere.

From Harold Hensel, via Facebook

The incredible images of 'dark snow' in Greenland tainted by massive forest fires - and experts say it is yet another sign of glacial change

  • 'Dark ice' effect caused by soot from forest fires, which then means ice melts faster
  • Taken using a drone by Dutch and Welsh research team in Greenland
  • Researchers admit they were 'stunned' by the extent of the dark ice  

Sept 2014

Update of Dr. Malcolm Light and Sam Carana's methane graph showing the point when methane becomes the dominate controlling factor of the climate.

The second poster shows a design to decompose methane in the atmosphere. The Lucy Project would be especially useful to decompose methane from a sudden burst in the East Siberian and Laptev Sea. The abstract for the Lucy Project has been accepted and published by the American Meteorological Society. It will be presented at the Annual Meeting in New Orleans on January 18th, 2016 in New Orleans.

There are heavy amounts of methane hydrates in the Laptev Sea. There are also "torches" of methane here. Dr. Shakova says that between the Laptev and East Siberian Sea, there are 50 billion tons of "free" methane here available to come up at any time. A sudden burst of this methane would be overwhelming. There are about 5 to 6 billion tons of methane in the atmosphere now. It is imparitive that we have a method of decomposing methane ready

The Gakkle Ridge just happens to be right under this area. It is an earthquake prone area also.

Earthquakes in and near the Laptev Sea.

Meanwhile we have a (relative) heat wave in Greenland

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