Antarctica on the Brink: NASA Emeritus Scientist Warns of Dramatic Loss of Glaciers
Monday, 14 March 2016 00:00 By Dahr Jamail, Truthout | Interview- font size
"Every degree of heat increase melts an additional 30 feet of ice, each year," says Robert Bindschadler, who worked for 35 years as a glaciologist at NASA's Goddard Space Flight Center. (Photo: Melting Iceberg via Shutterstock)
Scientific reports about the increasing pace of melting ice -- in all its forms around the planet -- are being published on a nearly daily basis.
A study published in January revealed a dramatic increase in melt rates on Antarctica's most stable ice shelf, when it showed that melting rates were 25 times higher than expected.
This disconcerting news comes a year after another study, which showed that the largest glacier in eastern Antarctica (Totten Glacier), which by itself contains the ice equivalent of a 20-foot rise in global sea levels, is melting due to warming ocean waters.
Other reports showing how increasingly warm ocean waters are contributing to an accelerating melting of large portions of Antarctica continue to be published on a regular basis.
NASA emeritus scientist Robert Bindschadler, who worked for 35 years as a glaciologist at NASA's Goddard Space Flight Center, is warning the global community about impending sea level rise. He is also doing what he can to educate people about the mechanisms causing the rapidly increasing melting of our polar regions, with the hope that it will make us more mindful of our carbon dioxide emissions, which have created the crisis of anthropogenic climate disruption (ACD).
Bindschadler led 18 field expeditions to Antarctica, and has participated in many other expeditions to glaciers and ice caps around the world. He actively developed applications that measure ice velocity and elevation using both visible and radar imagery, monitor melt of and snowfall on ice sheets by microwave emissions, and detect changes in ice sheet volume by repeat space-borne radar altimetry (using satellites to measure ice sheet thickness).
Bindschadler, who has published over 130 scientific papers, has advised the US Congress and the vice president on the stability of ice sheets and ice shelves and served on many scientific commissions and study groups as an expert in glaciology and remote sensing of ice. He also has degrees in astronomy and physics.
A winner of numerous scientific awards, Bindschadler continues to be a leader in the public conversation around the climate's impact on the world's ice sheets and glaciers. Although he is retired, he maintains an active interest in the dynamics of glaciers and ice sheets, investigating how remote sensing can be used to improve our understanding of the role of ice in the earth's climate.
A little more than a year after first interviewing Bindschadler, Truthout spoke with him again to get an update on his concerns about Antarctic glaciers, the melting of Greenland and the Arctic sea ice, and sea level rise in the future.
Dahr Jamail: The world's glaciers are in peril. A disturbing report has shown that they have shrunk to their lowest levels ever witnessed in the history of record-keeping. They are melting at an accelerating rate - two to three times faster than the 20th century average melt rate. As if to punctuate the findings of the report, the world's fastest melting glaciers, located in Greenland, a short while ago lost the largest amount of ice on record in just a 48-hour period. How much faster should we expect this kind of melting to increase?
Robert Bindschadler: Two things cause concern: One is the dynamics [ocean dynamics]; the other is surface mass balance, which is how much melting of the surface is taking place that is running into the ocean. Greenland has to be a concern for both of those. Right now, each of those two aspects is contributing to generate about half the ice loss in Greenland. Surface melting is increasing, so that has to be a concern. So that is part of the increasing contribution to sea level rise.
"Losing the land glaciers leads to other extremely serious problems, like lack of water for drinking and irrigating crops."
Also, Greenland is a player in this dynamic contribution that we still do not understand.... There are complex triggering mechanisms like atmospheric and oceanic heat that both open the valves and pull the corks totally out of the bottles - bottles meaning the ice that was previously holding the ice sheets in place and keeping them from flowing down into the water - and the ice flows faster into the oceans. That dynamic response is what we are trying to understand better, because it's an oceanographic and an atmospheric scientist's problem as well as one for glaciologists.
But we are seeing immediate increases to sea level there [in Greenland], and a dynamic response that could be significant and play out over decades, not centuries, and that is likely to be triggered in both Greenland, Washington State, Alaska and other places.
Triggering it is complex, with the aforementioned linkages, but also the evolution of that. Exactly how does the ice sheet respond as it continues to deliver ice and melt? How fast does that evolve? It may not evolve quite as rapidly as models suggest, but then again maybe it does. We see tidewater glaciers making catastrophic retreats in Greenland, and we are trying to see if ice sheets can respond the same way. It could well be on decadal time scales, not measured in centuries as it was in the past.
The surface melting in Greenland, though, is immediate: We are sure of it, and it is easiest to measure. [NASA published a recent study showing that the ice covering Greenland is melting faster than previously believed. NASA has also published an intriguing short video that shows the accelerating melting of Greenland. The National Research Council of the National Academies has recently published similar findings.]
In the Arctic, things continue to look grim. On September 11, 2015, Arctic sea ice dropped to its fourth-lowest level on record, amid what is now a decades-long ACD-generated decline. It seems clear we should expect this trend to continue, correct?
Generally each year this is increasing. It is anticipated as a positive feedback mechanism, as once you expose the sea ice cover you expose more dark ocean that absorbs more solar energy, which speeds it all up. We have known this for 30 years. It is a very strong, very disturbing positive feedback mechanism with obvious global implications.
One thing we don't hear too much about amidst the general conversation about ACD is the loss of land ice, both in the Arctic and elsewhere around the world, like in Alaska, the Andes and glaciers in Central Asia. Another recent study provided some worrisome news about glaciers in Central Asia, where it is now estimated that they have melted away four times faster than the global average since the early 1960s, losing more than one-quarter of their total mass in that time frame. Given that glaciers comprise a primary water source for millions of people in China, Kyrgyzstan, Kazakhstan and Uzbekistan, this does not bode well. How much impact does this have on sea level rise, and what trends are you seeing?
If all the land ice melts, all the ice caps, land glaciers, etc. ... you would still only get less than half a meter [of] sea level rise globally. But this remains a concern, because this is at the front edge, as this component comes into play with warming. You don't need a lot of complex dynamics to melt the land glaciers. It's like Greenland's surface; it just melts without other factors. But losing the land glaciers leads to other extremely serious problems, like lack of water for drinking and irrigating crops.
"Every degree of heat increase melts an additional 30 feet of ice, each year. So that is a powerful heat gun."
There are IPCC [Intergovernmental Panel on Climate Change] glaciologists monitoring this and trying to quantify how climate changes are manifesting in the reduction of glaciers, and most of their basic projections are that there will be a lot of melting and reduction in the next few decades, then a trailing off as less ice of this type exists around the globe, then progressing into subsequent decades where there will only be little patches [of glacial ice on land] that remain. This assessment includes the Andes and Himalaya, and Alaska, where the bigger reservoirs are.
I think at least half of all the ice in North America and the Himalaya could be gone by 2100. That assessment is from the IPCC, which is the most careful, conservative and comprehensive data. There will always be patches that exist longer, as there will always be glaciers in deep cirques facing north that never see the sun, but that half meter they have to contribute to sea level rise will be mostly played out by 2100.
When we last spoke you went into detail about the mechanics that cause climate scientists to be overly conservative in their predictions. Please sum up how this happens for our readers, since it is an ongoing phenomenon.
Climate models have been criticized as being too dramatic and overestimating response, but it's just the opposite: They tend to be too conservative because they are tied to data that was used from the beginning of studies. So they are tuned in to what has been going on, not able to capture all the acceleration that we are witnessing.
But as things continue to ramp up and the data captures more of that acceleration, the models will then project more acceleration. But in general, they tend to underestimate these positive feedbacks. Our observations compared to past projections are showing that things are continually worse than we had projected them. That is not a cause to distrust the models, but a cause for broader concern for what is happening around the planet.
In Antarctica, a world-renowned climate scientist recently reported that the "sleeping giant" Eastern Antarctic ice sheet, which comprises the vast majority of the ice in Antarctica, is far more sensitive to ACD than we previously believed. If it melted, it would contribute 50 meters to global sea level rise. What are your observations about the possibility of this occurring?
There are regions of Antarctica where the ice is sitting on a bed that is well below sea level. So this feature is marine ice sheet instability, which is driving a lot of the WAIS [Western Antarctic ice sheet] focus, for sure. When we look at paleoclimate data and try to assess how high sea level was long ago, you have to add in some of the melt from EAIS [Eastern Antarctic ice sheet], as Greenland, Washington, Alaska and other land ice areas melting do not provide enough sea level rise to match what we found in the paleoclimate data ... EAIS ice core suggest a fairly stable configuration over the last hundreds of thousands [of] years. I'm still far more concerned about the WAIS as the big player, along with Greenland as the near-term concern, than I am about the EAIS. I've yet to see data to shift my focus away from Greenland and the WAIS.
[Another study reveals that all of the ice in the Antarctic will melt if all of the fossil fuels that we are currently aware of are burned. Given that there is no evidence to support the idea that global political will is aimed at weaning the global economy off fossil fuel use, we must take this information very seriously. The study shows that, if Antarctica melts, global temperatures will rise an average of 12 degrees Celsius, and major cities like Berlin, Shanghai, New York and numerous others will cease to exist.]
Given the dramatic impacts that the loss of most land ice, eventually the Arctic sea ice and the WAIS, and possibly parts of the EAIS, will have on the planet and its species, it is important for people to become better acquainted with the processes that are causing the melting. In this way, perhaps more knowledge of what our emissions are doing to impact the natural world and its systems could cause people to be more mindful when it comes to driving a car or hopping on another jet. Please go into detail about how our already having warmed the planet just 0.85 degrees Celsius is causing tectonic shifts in the atmospheric and ocean current circulatory systems of Earth.
Speaking about what is impacting Antarctica, the basics of it are that the atmospheric winds influence the ocean and the ocean affects the ice. These are all at play in Greenland, too. In the Antarctic, you have the circumpolar winds rotating clockwise around the continent, and these isolate the continent.
Two things result from this: The first is that the Antarctic is isolated from other weather patterns, so as the rest of the world has warmed, the Antarctic hasn't warmed as much. So that causes an increased isolation, as the temperature gradient of the warm tropics and the cold Antarctic increases, that causes an increase in pressure. That pressure has increased the speed of the circumpolar winds.
The second thing that results from this is the winds drag the ocean along with it. So there is a huge, strong, powerful, broad current, the Antarctic circumpolar current, that is spun up and drug along by the winds. So now we have the ocean going around faster and faster because the air is dragging it faster. In the Southern Hemisphere, because of the rotation of the planet, the faster ocean water is turning a little more to the left, and that steers it away from the continent of Antarctica, so that is forcing water from a greater depth to upwell high enough for it to spill onto the continental shelf. And this is warm water because in the tropics you have warm water on top and cold water down deep. In the polar oceans, you have three layers, a cold surface, then a warm layer, then the cold deep waters, because sea ice freezes and melts every year, hence the creation of the cold surface layer. So it's the surface layer being pushed away, and the upwelling is warm.
So once it does that, the continental shelf is tilted down toward the ice sheet, so the warm, dense, salty water gets onto the shelf, and hugs the shelf, and flows down toward the ice sheet, contacting it at the grounding zone where the ice is, melting the ice very, very rapidly. Every degree of heat increase melts an additional 30 feet of ice, each year. So that is a powerful heat gun.
In the United States, a glaciologist with more than 30 years of experience in the field recently described the loss of glaciers in the Pacific Northwest as "disastrous." "This is the single biggest volume loss in the last 50 years," he said of the region that has seen its glaciers shrink by between 25 and 40 percent since the mid-1980s. Another scientist estimates the region's glaciers are already smaller than they have been for at least the last four millennia. Dramatic reports like this are coming out on a nearly daily basis. However, we will still have rebound years of cooler temperatures and higher snowfalls, which ACD deniers like to point toward as "proof" that there is no "global warming." Talk about the pitfalls of looking at short-term results that point in either direction.
It's tempting, even for scientists, if there's a really warm year, to point to that and say, "See!" But if there's a rebound the next year, the naysayers will be pointing to that and saying, "See!"
Scientists have to discount the individual year-to-year behavior and stay focused on the trends. There is more confidence in the trends. But especially in the Pacific Northwest where you and I live, these past 12 months have been useful from a communication aspect, because we've been experiencing what I have to say is the new normal ... the drought, the significantly reduced snowpacks. And there's been talk of this throughout the winter: In the media here, they are mentioning the increased likelihood of droughts.
Then this last summer, when our rivers were closed to fishing, that is when educators talk about this as being a "teachable" moment. This is more common now. Once people experience something, it is no longer theoretical. This can then be used as an example of what the models are pointing out. So, more and more people are paying attention. Another example is the wildfires being a direct consequence of the drought. Because people are actually experiencing these things now, it's easier to talk about what it's going to look and feel like. The dots we are trying to connect are getting closer and closer together.
DAHR JAMAIL
Dahr Jamail, a Truthout staff reporter, is the author of The Will to Resist: Soldiers Who Refuse to Fight in Iraq and Afghanistan, (Haymarket Books, 2009), and Beyond the Green Zone: Dispatches From an Unembedded Journalist in Occupied Iraq, (Haymarket Books, 2007). Jamail reported from Iraq for more than a year, as well as from Lebanon, Syria, Jordan and Turkey over the last ten years, and has won the Martha Gellhorn Award for Investigative Journalism, among other awards.
His third book, The Mass Destruction of Iraq: Why It Is Happening, and Who Is Responsible, co-written with William Rivers Pitt, is available now on Amazon. He lives and works in Washington State.
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is dan de vorige keer, dan gaan we in hoger beroep!".
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