Here’s a link to home base for current NASA science on Greenland’s meltdown.
A new NASA study says that an increase in Antarctic snow accumulation that began 10,000 years ago is currently adding enough ice to the continent to outweigh the increased losses from its thinning glaciers.
The research challenges the conclusions of other studies, including the Intergovernmental Panel on Climate Change’s 2013 report, which says that Antarctica is overall losing land ice…
“We’re essentially in agreement with other studies that show an increase in ice discharge in the Antarctic Peninsula and the Thwaites and Pine Island region of West Antarctica,” said Jay Zwally…lead author of the study…”Our main disagreement is for East Antarctica and the interior of West Antarctica – there, we see an ice gain that exceeds the losses in the other areas.” Zwally added that his team “measured small height changes over large areas, as well as the large changes observed over smaller areas.”…
But it might only take a few decades for Antarctica’s growth to reverse, according to Zwally. “If the losses of the Antarctic Peninsula and parts of West Antarctica continue to increase at the same rate they’ve been increasing for the last two decades, the losses will catch up with the long-term gain in East Antarctica in 20 or 30 years — I don’t think there will be enough snowfall increase to offset these losses.”
Of course, that last sentence disappears in publications dedicated to ideology instead of scientific reality. This would be the appropriate place for a lecture on geologic time, climate-time vs meteorologic-time. I think it likely you already know what I’m talking about.
And, so does the clown show that clutches at straws hoping their children and grandchildren will find themselves in the magic world which lives only in the galaxy of kinder, gentler intellectual ennui.
RTFA for more details of the analysis. There are a few decent studies around on the significant differences between the northern and southern hemispheres of this small ball of mud we live on. Sooner or later, I’ll have to work something up that points out the whys and wherefores.
A previously unknown canyon has been discovered in Greenland, hidden beneath the ice. It is at least 750 kilometres long. To put that in perspective, imagine a ten kilometre wide gorge, up to 800 metres deep, running from the Southern coast of England and into Scotland. This is on the same scale as parts of the Grand Canyon.
Jonathan Bamber, who led the research, was originally mapping Greenland’s bedrock, which was previously thought to be relatively flat and smooth. “Unexpectedly, we found an enormous apparent formation,” he said. “We looked at it in more detail, and realised it was a canyon.”
The canyon, which is thought to predate glaciation, has remained hidden beneath two kilometres of ice for more than four million years. It has the characteristics of a meandering river channel, an ancient river system that Bamber thinks hasn’t been significantly modified by ice cover.
It is almost twice the length of the Grand Canyon, half as deep but almost as wide, and certainly the only feature in Greenland this long…
“This really is quite remarkable,” Bamber said. “In an age when you have Google street view covering the entirety of the inhabited world, when virtually every house is mapped. In this context, to discover a geological feature of such scale is astonishing…”
“We think the canyon is an efficient conduit for ice-melt from the glacier. If you want to model glacial movement – something that is ever more crucial due to global warming – then knowing about such topography is very important.”
The discovery shouldn’t affect our forecasts for future sea level in itself, but it does highlights that we still don’t know everything about the surface of our own planet.
Unexpected discoveries always lurk in the back of the mind of any researcher. It surely is a gas when something like this pops into focus and changes from anomalous shadow to a discrete discovery.
This ancient thaw may have caused sea levels to rise by approximately 20 metres, scientists report…in the journal Nature Geoscience.
The researchers, from Imperial College London, and their academic partners studied mud samples to learn about ancient melting of the East Antarctic ice sheet. They discovered that melting took place repeatedly between five and three million years ago, during a geological period called Pliocene Epoch, which may have caused sea levels to rise approximately ten metres.
Scientists have previously known that the ice sheets of West Antarctica and Greenland partially melted around the same time. The team say that this may have caused sea levels to rise by a total of 20 metres.
The academics say understanding this glacial melting during the Pliocene Epoch may give us insights into how sea levels could rise as a consequence of current global warming. This is because the Pliocene Epoch had carbon dioxide concentrations similar to now and global temperatures comparable to those predicted for the end of this century…
The East Antarctic ice sheet is the largest ice mass on Earth, roughly the size of Australia. The ice sheet has fluctuated in size since its formation 34 million years ago, but scientists have previously assumed that it had stabilised around 14 million years ago.
The team in this study were able to determine that the ice sheet had partially melted during this “stable” period by analysing the chemical content of mud in sediments. These were drilled from depths of more than three kilometres below sea level off the coast of Antarctica.
Analysing the mud revealed a chemical fingerprint that enabled the team to trace where it came from on the continent. They discovered that the mud originated from rocks that are currently hidden under the ice sheet. The only way that significant amounts of this mud could have been deposited as sediment in the sea would be if the ice sheet had retreated inland and eroded these rocks, say the team.
The academics suggest that the melting of the ice sheet may have been caused in part by the fact that some of it rests in basins below sea level. This puts the ice in direct contact with seawater and when the ocean warms, as it did during the Pliocene, the ice sheet becomes vulnerable to melting.
Carys Cook, co-author and research postgraduate from the Grantham Institute for Climate Change at Imperial, adds: “Scientists previously considered the East Antarctic ice sheet to be more stable than the much smaller ice sheets in West Antarctica and Greenland, even though very few studies of East Antarctic ice sheet have been carried out. Our work now shows that the East Antarctic ice sheet has been much more sensitive to climate change in the past than previously realised. This finding is important for our understanding of what may happen to the Earth if we do not tackle the effects of climate change.”
Meanwhile, Congress continues tax breaks and subsidies to oil companies which directly cost American taxpayers billion$ of dollars. What they cost the whole planet is so much more, so much more important and, therefore, unnoticed by know-nothings elected by idjits.
For several days this month, Greenland’s surface ice cover melted over a larger area than at any time in more than 30 years of satellite observations. Nearly the entire ice cover of Greenland, from its thin, low-lying coastal edges to its two-mile-thick center, experienced some degree of melting at its surface, according to measurements from three independent satellites analyzed by NASA and university scientists.
On average in the summer, about half of the surface of Greenland’s ice sheet naturally melts. At high elevations, most of that melt water quickly refreezes in place. Near the coast, some of the melt water is retained by the ice sheet and the rest is lost to the ocean. But this year the extent of ice melting at or near the surface jumped dramatically. According to satellite data, an estimated 97 percent of the ice sheet surface thawed at some point in mid-July.
Researchers have not yet determined whether this extensive melt event will affect the overall volume of ice loss this summer and contribute to sea level rise…
The melting spread quickly. Melt maps derived from the three satellites showed that on July 8, about 40 percent of the ice sheet’s surface had melted. By July 12, 97 percent had melted.
This extreme melt event coincided with an unusually strong ridge of warm air, or a heat dome, over Greenland. The ridge was one of a series that has dominated Greenland’s weather since the end of May. “Each successive ridge has been stronger than the previous one,” said Mote. This latest heat dome started to move over Greenland on July 8, and then parked itself over the ice sheet about three days later. By July 16, it had begun to dissipate.
Even the area around Summit Station in central Greenland, which at 2 miles above sea level is near the highest point of the ice sheet, showed signs of melting….”Ice cores from Summit show that melting events of this type occur about once every 150 years on average. With the last one happening in 1889, this event is right on time,” says Lora Koenig, a Goddard glaciologist and a member of the research team analyzing the satellite data. “But if we continue to observe melting events like this in upcoming years, it will be worrisome.”
I love the conservative calm of serious researchers.
There will be the flightier breed of enviro who will take this occurrence as exclusively owing to climate change. Which it may well be. But, it will take time and more observations over time – to determine that.
There will be Flat Earth climate deniers as foolish in their own special fear and trembling on behalf of purveyors of fossil fuels.
My guess? The global trend suggests we’re all screwed. Many Western democracies will wait until well after the fact to take notice.
Thanks, Uncle Dave
Daylife/Reuters Pictures used by permission
East Antarctica’s ice started to melt faster from 2006, which could cause sea levels to rise sooner than anticipated, according to a study by scientists at the University of Texas.
In the study published in Nature’s Geoscience journal, scientists estimated that East Antarctica has been losing ice mass at an average rate of 5 to 109 gigatonnes per year from April 2002 to January 2009, but the rate speeded up from 2006.
The melt rate after 2006 could be even higher, the scientists said.
“The key result is that [we] appear to start seeing a large amount of ice loss in East Antarctica, mostly in the long coastal regions (in Wilkes Land and Victoria Land), since 2006,” Jianli Chen at the university’s centre for space research and one of the study’s authors, told Reuters.
“This, if confirmed, could indicate a state change of East Antarctica, which could pose a large impact on global sea levels in the future,” Chen said…
Climate change is turning Antarctica’s ice into the one of the biggest risks for coming centuries. Even slight melting could drive up sea levels and could affect world’s cities.
Over the several years I have been studying climate change Antarctic ice was thought to be less-affected than the Northern Pole. Now that means and methods have improved, we get to figure out the bad news is universal.
note: at post time, the direct link to the study – in the Reuters article – was broken.