Tag Archives: Greenland

Greenland ice sheet not covered in soot

The uncertainty of science: A new study of the Greenland ice sheet has found that the darkening sensed there by satellites is not caused by dust and soot deposited by forest fires and industry but was instead caused by the slow degradation of the sensors on the satellites themselves.

In trying to explain the apparent decline in reflectivity, lead author Chris Polashenski, an adjunct assistant professor at Dartmouth’s Thayer School of Engineering and a research geophysicist at the U.S. Army Corps of Engineers Cold Regions Research and Engineering Laboratory, and his colleagues analyzed dozens of snow-pit samples from the 2012-2014 snowfalls across northern Greenland and compared them with samples from earlier years. The results showed no significant change in the quantity of black carbon deposited for the past 60 years or the quantity and mineralogical makeup of dust compared to the last 12,000 years, meaning that deposition of these light absorbing impurities is not a primary cause of reflectivity reduction or surface melting in the dry snow zone. Algae growth, which darkens ice, also was ruled out as a factor.

Instead, the findings suggest the apparent decline in the dry snow zone’s reflectivity is being caused by uncorrected degradation of sensors in NASA’s aging MODIS satellites and that the declining trend will likely disappear when new measurements are reprocessed.

In other words, this story is another case of fear-mongering environmentalists and climate scientists (but I repeat myself) prematurely blaming human activity on the destruction of the environment.

Largest glacier calving event ever filmed

An evening pause. Hat tip Phill Oltmann. I had sworn I had posted this already, but now can’t find it on BtB. And even if I have posted it, it is worth watching again. My only comment is that I am baffled by the film’s description of the event as “horrifying.” I don’t find this natural event horrifying, I find it awe-inspiring. It reminds us that the scale of the universe if far far beyond anything we can imagine.

A new study has found that the glaciers of Greenland are not behaving as predicted.

The uncertainty of science: A new study has found that the glaciers of Greenland are not behaving as predicted.

In northwestern Greenland, for example, where most of the glaciers move relatively quickly and flow directly into the sea rather than ending on land, average speed jumped by 8% between 2000 and 2005 and rose another 18% from 2005 to 2010. Nevertheless, the researchers report online today in Science, the glaciers in this region showed no uniform pattern of acceleration. About one-third flowed at the same rate throughout the decade, one-fourth slowed during the interval, and about 15% slowed during the first half of the decade and then surged from 2005 to 2010.

Similarly, many of the individual glaciers in southeastern Greenland don’t follow the region’s overall trend. Although the average speeds for these glaciers increased by 28% over the decade, substantial accelerations by some glaciers were balanced by considerable slowing by others. About 43% of the glaciers in the region sped up between 2000 and 2005, but around 25% slowed down by more than 15% from 2005 to 2010.

In other words, if there is any warming, it hasn’t manifested itself in a predictable manner in the glaciers of Greenland. In fact, the data above suggests instead that if there has been any warming, it either has been far less than predicted, or has had relatively little influence on the Greenland ice sheet.

Times Atlas shows ice free areas of Greenland that are not ice free

When faith trumps data: The most recent edition of the Times Atlas incorrectly shows large areas of Greenland free of ice, claiming this was caused by global warming, even though those areas remain ice-covered. More here.

The Scott Polar group, which includes director Julian Dowdeswell, says the claim of a 15% loss in just 12 years is wrong. “Recent satellite images of Greenland make it clear that there are in fact still numerous glaciers and permanent ice cover where the new Times Atlas shows ice-free conditions and the emergence of new lands,” they say in a letter that has been sent to the Times. “We do not know why this error has occurred, but it is regrettable that the claimed drastic reduction in the extent of ice in Greenland has created headline news around the world. There is to our knowledge no support for this claim in the published scientific literature.

The icecaps of Greenland and Antarctica: are they melting?

NASA scientists have published a paper warning that there is growing evidence that the melting at the polar caps is accelerating. From the press release:

The pace at which the polar ice sheets are losing mass was found to be accelerating rapidly. Each year over the course of the study, the two ice sheets lost a combined average of 36.3 gigatonnes more than they did the year before. In comparison, the 2006 study of mountain glaciers and ice caps estimated their loss at 402 gigatonnes a year on average, with a year-over-year acceleration rate three times smaller than that of the ice sheets.

Several things to note after reading the actual paper:

Imaging the ground under the Greenland ice sheet

In a paper published today in Geophysical Research Letters of the American Geophysical Union, scientists describe how they have been able to produce remarkably detailed images of the ground buried almost a mile under the ice sheet of Greenland. These radar techniques are the same used in the past by spacecraft to image the hidden surface of Venus, only far more sophisticated.

The grooves on the surface of Greenland

This image from the paper compares the radar image of the Greenland surface (on the left) to an photograph of a known surface feature in the Northwest Territories of Canada, produced thousands of years ago by the giant icesheets of the last Ice Age. Both are at the same scale, about a third of a mile across, and are looking at the surface at an oblique angle of about 45 degrees. With the radar-produced image on the left, sunlight is simulated as coming from the right, with the elevation increasing as the colors go from green (lowest) to yellow to brown to purple (highest).

The long grooves, generally 30 to 100 feet deep and extending sometimes several miles, are produced as the icesheet slides across the ground. In the radar image, however, these grooves are slowly being ground out now.

It is the resolution of this technique that is so exciting. That they can look through ice almost a mile thick and resolve objects that are only tens of feet across tells me that someday it will be possible for spacecraft to map the smallest features on the surface of Venus or Titan. More exciting, this suggests that the technology will one day exist to even map the unknown surface of gas giants like Jupiter or Saturn, and do it in breathtaking detail.


Greenland icecap is not melting

Steve Goddard has posted on Anthony Watt’s webpage a very detailed update on the state of the icecap covering Greenland. Surprise! There are no signs of it disappearing anytime soon. (Note that you might have to scroll to the right to see the text of Goddard’s post, as on some computers Watts’s webpage is unfortunately far too wide for the screen.)