Search Results for Tag: research
As I continue to prepare for my trip to Svalbard and the Arctic waters around the archipelago, into the Polar Night, the title of a website strikes me as particularly appropriate: Mare Incognitum is the umbrella title for a group of Arctic research projects, including the one I will be joining this weekend at the harbour of the Arctic research base at Ny Alesund, Spitsbergen. The title was chosen to reflect the group’s view of the Arctic as “one of the least known marine ecosystems of the planet”.
DateJanuary 8, 2015 | 3:56 pm
TagsArctic, Arctic Frontiers, Climate, IPY, Mare incognitum, Norway, Ny Alesund, Polar night, research, science, sea ice, Svalbard, Tromso
Polar Ice at UN Bonn Climate Talks
The delegates to the UN climate meeting currently taking place here in Bonn are receiving an urgent appeal from polar scientists to cut emissions to slow polar ice melt and give low-lying coastal regions more time to adapt to rising sea levels.
I was very interested to hear about a side-event being held here this evening, at which the authors of this year’s key studies on developments in the Antarctic will be explaining the connections between melting polar ice and climate change impacts like rising seas, affecting regions as diverse as small island states, Bangladesh or Florida in the USA.
I interviewed Anders Levermann from PIK, the Potsdam Institute for Climate Impacts Research and Pam Pearson, Director of ICCI, the International Cryosphere Climate Initiative, both in Bonn for the event.
The ICCI decided to bring the cryosphere into the Bonn talks to sensitize delegates to the dramatic developments in the Antarctic in particular, says Pearson. Ice Blog readers (and I was so delighted to hear Pam herself is one!) will remember posts earlier this year on melting in the East and West Antarctic. I also covered these in articles for DW. The shocking thing is that the Antarctic, even East Antarctica, which was until relatively recently considered so cold it had to be safe from global warming, is already being affected by climate change. The papers on the West Antarctic even described the melt trend as “irreversible”.
“We have entered an era of irreversible climate change”.
Today, Anders Levermann, author of the East Antarctic paper and one of the world’s leading Antarctic researchers, told me “we have entered a new era of climate change, witnessed the tipping of the West Antarctic ice sheet, and this is irreversible”.
That should really shock people into action, you would think. But climate negotiations are moving, as one of the experts said to me at the meeting “at a glacial pace”. As we can see in Antarctica, though, and Greenland and other regions, those glaciers are speeding up. Maybe there is hope for the climate talks yet!
The announcements by the USA and China on possible emissions cuts have brought a new “buzz” to the Bonn conference. The fact that the key emitters could finally be getting the message and preparing to move, with the impacts of climate change hitting their own countries, has to be a positive signal. Pearson confirmed to me that people in the sunshine state of Florida, where she lives, had become more aware of the importance of melting ice caps with increasing floods and storms.
As Levermann says, Antarctica and Greenland have a huge potential to raise sea level further than previously anticipated. He was lead author on the IPCC report chapter on sea level rise. The latest IPCC report factored in some of the likely impacts from melting ice in these regions for the first time. Of course the latest research was not yet included. For the 21st century forecast, this will not make a lot of difference, says Levermann. But the fact that this irreversible Antarctic melt is now underway will make a big difference to coming generations.
There are those who dispute whether the warming of the ocean, which is causing the Antarctic melt (unlike the surface melt on Greenland) is man-made. Levermann does not rule out natural variation as a possible influence. But ultimately, he says, that is irrelevant. Greenhouse gas emissions and so human interference are warming the planet, and any further warming, whatever the cause, will speed up ice melt. So cutting emissions is the way to slow it down and, Pearson adds, gives people time to adapt to rising seas.
The combination of models based on the principles of physics, using a higher resolution than ever before, and evidence from ice cores showing what happened in the past, make for a high degree of certainty about these ice developments, says Levermann.
“The level of warming will determine the rate with which we discharge West Antarctica, and we can still prevent the tipping of East Antarctica”, the cryosphere experts told us here in Bonn.
That is a huge responsibility. Here’s hoping the message will make it into the hearts and minds of those negotiating the future of the earth’s climate and the governments they represent.
DateJune 13, 2014 | 2:34 pm
Keeping Greenland in focus
Two interesting publications relating to Greenland caught my eye over the past few days. But it has not proved easy to get them onto the international news agenda. Given the huge importance of the Greenland ice sheet to the planet’s future, this is frustrating to say the least. Fortunately there is the Ice Blog.
The first research relates to a study about the role of ash from fires in bringing about large-scale surface melting. The other predicts Greenland will be a far greater contributor to sea rise than expected.
Let me start with the latter, published in Nature Geoscience. Scientists from the University of California – Irvine and NASA glaciologists have found previously uncharted long deep valleys under the Greenland Ice Sheet. Since these bedrock canyons are well below sea level, they are much more vulnerable to warm ocean waters than previously thought. When warmer Atlantic water hits the fronts of hundreds of glaciers, the edges will erode much further than previously assumed, releasing far greater amounts of water.
Ice melt from the subcontinent has already accelerated, as warmer marine currents have migrated north, the authors say. Older models predicted that once higher ground was reached in a few years, the ocean-induced melting would halt. Greenland’s frozen mass would stop shrinking, and its effect on higher sea waters would be curtailed.
“That turns out to be incorrect. The glaciers of Greenland are likely to retreat faster and farther inland than anticipated – and for much longer – according to this very different topography we’ve discovered beneath the ice,” says lead author Mathieu Morlighem, a UC Irvine associate project scientist, on the university website. “This has major implications, because the glacier melt will contribute much more to rising seas around the globe.”
To obtain the results, Morlighem developed what he says is a breakthrough method that for the first time offers a comprehensive view of Greenland’s entire periphery. It’s nearly impossible to accurately survey at ground level the subcontinent’s rugged, rocky subsurface, which descends as much as 3 miles beneath the thick ice cap.
Since the 1970s, limited ice thickness data has been collected via radar pinging of the boundary between the ice and the bedrock. Along the coastline, though, rough surface ice and pockets of water cluttered the radar sounding, so large swaths of the bed remained invisible.
Measurements of Greenland’s topography have tripled since 2009, thanks to NASA Operation IceBridge flights. But Morlighem says he quickly realized that while that data provided a fuller picture than the earlier radar readings, there were still major gaps between the flight lines.
To reveal the full subterranean landscape, he designed a novel “mass conservation algorithm” that combined the previous ice thickness measurements with information on the velocity and direction of its movement and estimates of snowfall and surface melt.
The difference was dramatic, says Morlighem. What appeared to be shallow glaciers at the very edges of Greenland are actually long, deep fingers stretching more than 100 kilometers (almost 65 miles) inland.
“We anticipate that these results will have a profound and transforming impact on computer models of ice sheet evolution in Greenland in a warming climate,” the researchers conclude.
“Operation IceBridge vastly improved our knowledge of bed topography beneath the Greenland Ice Sheet,” said co-author Eric Rignot of UC Irvine and NASA’s Jet Propulsion Laboratory. “This new study takes a quantum leap at filling the remaining, critical data gaps on the map.”
Other co-authors are Jeremie Mouginot of UC Irvine and Helene Seroussi and Eric Larour of JPL. Funding was provided by NASA.
This is the same team that reported on accelerated glacial melt in West Antarctica, as discussed in an earlier Ice Blog post. Together, the papers “suggest that the globe’s ice sheets will contribute far more to sea level rise than current projections show,” Rignot said.
Indeed. These scientists are telling us the IPCC forecasts were way too low. This could have huge consequences for coastal communities all around the globe.
Unfortunately, a lot of people (even those you would expect to know better) tend to mix up “Arctic” and “Antarctic”. It all goes into the category of “melting ice”, and they think they have heard it all before. What they still don’t realize is that this is something that concerns us all, and that these two polar areas are of huge significance to the world climate as a whole and global sea level. When those two Antarctic studies were released, there was a flurry of news coverage. The challenge for us journalists is how to follow this up and stop the attention curve from dropping.
The other interesting piece of recent Greenland research was conducted by the Dartmouth College Thayer School of Engineering and the Desert Research Institute and reported in the Proceedings of the National Academy of
Sciences. It concludes that ash from Northern hemisphere forest fires combined with rising temperatures to cause large-scale surface melting of the Greenland ice sheet in 1889 and 2012.
The researchers say their findings contradict conventional thinking that the melting was driven by warming alone.
The findings suggest that continued climate change will result in nearly annual widespread melting of the ice sheet’s surface by the year 2100.
Melting in the dry snow region does not contribute to sea level rise, but when the meltwater percolates into the snowpack and refreezes, the surface is less reflective. This reduces the albedo.
Let me give the (almost) last word to the study’s lead author Kaitlin Keegan.
“With both the frequency of forest fires and warmer temperatures predicted to increase with climate change, widespread melt events are likely to happen much more frequently in the future”.
DateMay 23, 2014 | 2:39 pm
Cryosphere in Crisis?
You can’t say the latest research results on the thinning of the West Antarctic ice sheet didn’t make the media. From the news agencies through the quality media and even publications not known for their detailed science or environment coverage – nearly all reported that two separate studies each independently come to the conclusion that parts of the West Antarctic ice sheet are already “collapsing”. They say this could result in a considerable sea level rise within the next century or two. This would have devastating consequences for low-lying coastal areas around the globe.
No-one can really say they didn’t know about this. For once, the Antarctic ice has made into the headlines of the mainstream media. This is the region people tend to think of as having “eternal ice”, where global warming will “not make much difference”. There are those who criticize the media for sensationalism or exaggeration by taking over the term “collapse” for a process which will still take hundreds to thousands of years. See for example Andrew Revkin’s post on Dot Earth (New York Times), (and an excellent response by Tom Yulsman in ImaGeo: (Discover Magazine). But, semantic discussions apart – as Yulsman puts it:
“On a human timescale, 200 years or more for the start of rapid disintegration is a very long time indeed. But on a geologic timescale, it is the blink of an eye. And that’s important to keep in mind too — that in a blazing flash, geologically speaking, we humans are managing to remake the life support systems of our entire planet. This is why I think today’s news may eventually be seen as having historic significance”. At any rate, he concludes “it is yet another clear sign that human-caused changes to the planet once regarded as theoretical are now very real”.
Indeed Tom. The question is: what are we going to do about it? Has it set the alarm bells ringing? Did anybody see a rash of reactions promising quick action on reducing emissions to mitigate climate change? If so, please point me in the right direction. So far, I haven’t seen any indication of anything other than business as usual.
The West Antarctic ice sheet contains so much ice that it would raise global sea level by three to four meters if it melted completely. As it sits on bedrock that is below sea level, it is considered particularly vulnerable to warming sea water. Until now, scientists assumed it would take thousands of years for the ice sheet to collapse completely. The two new studies indicate that could happen much faster – as early as 200 years from now or, at the most, 900. Both research teams, using different methods and looking at different parts of the ice sheet, conclude that the trend is probably unstoppable.
The NASA study published in “Geophysical Research Letters” uses data from satellites, planes, ships and measurements from the shelf ice to examine six large glaciers in the Amundsen Sea over the last 20 years. The second report, from the University of Washington published in the journal “Science,” uses computer models to study the Thwaites glacier. It is considered of particular importance because it acts as a type of “lynch pin”, holding back the rest of the ice sheet.
According to NASA researcher Eric Rignot, the glaciers in the Amundsen Sea sector of West Antarctica have “passed the point of no return.” He told journalists this would mean a sea level rise of at least 1.2 meters (3.93 feet) within the next 200 years.The University of Washington scientists worked out, using topographical maps, computer simulations and airborne radar, that the Thwaites glacier is also in an early stage of collapse. They expect it to disappear within several hundred years. That would raise sea levels by around 60 centimeters (23.62 inches). The NASA study showed that sea level rises of 1.2 meters are possible
The good news, according to author Ian Joughlin, is that while the word “collapse” implies a sudden change, the fastest scenario is 200 years, and the longest more than 1,000 years. The bad news, he adds, is that such a collapse may be inevitable: “Previously, when we saw thinning we didn’t necessarily know whether the glacier could slow down later, spontaneously or through some feedback,” Joughlin says. “In our model simulations it looks like all the feedbacks tend to point toward it actually accelerating over time. There’s no real stabilizing mechanism we can see.”
The latest IPCC report does not adequately factor ice loss from the West Antarctic ice sheet into its projections for global sea level rise, on account of a lack of data. These “will almost certainly be revised upwards,” according to Sridar Anandakrishnan from Pennsylvania State University at the presentation of the University of Washington study. The scientist was not involved in the research.
NASA glaciologist Rignot said he was taken aback by the speed of the changes. “We feel this is at the point where … the system is in a sort of chain reaction that is unstoppable,” he said.
Rignot also makes the key point that this development tells us not only about the area down at the South Pole, but about the whole climate system: “This system, whether Greenland or Antarctica, is changing on a faster time scale than we anticipated. We are discovering that every day.”
My last two blog posts have been about melting of the Greenland ice sheet and melting even in the East Antarctic, which is usually cited as the last bastion against ice-destroying climate change. We are subjecting our cryosphere to huge pressures and have set a “snowball” rolling, which is picking up momentum and will ultimately carry masses of ice into a rising ocean.
Rignot says even drastic measures to cut greenhouse gas emissions could not prevent the collapse of the West Antarctic ice sheet. That is a terribly depressing thought. I would like to think this will prove wrong. But if there is any chance to avert that disaster and preserve our polar ice for thousands of years rather than just a few hundred, surely the time for action is now?
DateMay 14, 2014 | 2:46 pm
Will Antarctic share Arctic’s fate?
While the Arctic is melting twice as fast as the rest of the planet, and protests continue against the race for oil at huge risk to the sensitive environment, the icy regions around the south pole were long considered immune to climate change. But melting glaciers on the Antarctic Peninsula in recent years sparked doubts in the scientific community about just how stable the western region of Antarctica really is. Earlier this year, I wrote an article on the irreversible melt of the Pine Island glacier on western Antarctica. The huge iceberg that broke off last November has been in the news again, heading for the open sea.
Only the huge icy vastness of Eastern Antarctica still appeared to be safe from the perils of a warming climate. Now experts from Germany’s Potsdam Institute for Climate Impact Research (PIK) have published findings indicating that this too might no longer be the case. In a study published in “Nature Climate Change“, they write that the melting of just a small volume of ice on the East Antarctic coast could ultimately trigger a discharge of ice into the ocean which would result in unstoppable sea-level rise. They are talking about tomorrow or the next decade. Still, the prospect of more irreversible thawing in the Antarctic is a very worrying one.
“Previously, only the West Antarctic was thought to be unstable. Now we know that the eastern region, which is ten times bigger, could also be at risk”, says Anders Levermann, co-author of the study. The findings are based on computer simulations which make use of new, improved data from the ground beneath the ice sheet.PIK scientist Levermann was one of the lead authors of the sea-level section in the latest IPCC report.
“The Wilkes Basin in East Antarctic is like a bottle that is tilted”, says Matthias Mengel, lead author of the new study.”If you take out the cork, the contents will spill out”. At the moment, the “cork” is formed by a rim of ice at the coast. If that were to melt, the huge quantities of ice it holds back could shift and flow into the ocean, raising sea levels by three to four meters. Although air temperatures over Antarctica are still very low, warmer ocean currents could cause the ice along the coast to melt.
So far, there are no signs of warmer water of this sort heading for the Wilkes Basin. Some simulations suggest though that the conditions necessary for the “cork” to melt could arise within the next 200 years. Even then, the scientists say it would take around 2000 years for sea level to rise by one meter.
According to the simulations, it would take 5,000 to 10,000 years for all the ice in the affected region to melt completely. “But once this has started, the discharge will continue non-stop until the whole basin is empty”, says Mengel. “This is the basic problem here. By continuing to emit more and more greenhouse gases, we could well be triggering reactions today that we will not be able to stop in the future. ” Indeed.
The IPCC report predicts a global sea-level rise of up to 16 centimeters this century. As this could already have devastating impacts on many coastal areas around the globe, any additional factor is of key importance to the calculations. “We have presumably overestimated the stability of East Antarctica”, says Levermann. Even the slightest further increase in sea level could aggravate flooding risks for coastal cities like New York, Tokyo or Mumbai.
At the moment, the largest contribution to Antarctic ice loss and rising sea levels comes from the Pine-Island glacier in West Antarctica. As I mentioned at the start, a huge iceberg, which broke off from the glacier last year, is currently floating into the open waters of the Southern Ocean. French glaciologist Gael Durand from Grenoble University told me in an interview the huge glacier had already reached a point where its continued melting is irreversible, regardless of air temperature or ocean conditions.
DateMay 5, 2014 | 2:51 pm