Last night I wanted to see footage on television of the huge island of ice that has broken off of the Petermann glacier in Greenland. It’s the biggest such event in the Arctic for 50 years, launching a massive iceberg that has four times the area of Manhattan and is 600 feet thick. “The so-called “ice island” covers a hundred square miles (260 square kilometers) and holds enough water to keep U.S. public tap water flowing for 120 days.”
I thought that some enterprising Greenlander, perhaps from the Greenland Ice Patrol which monitors ice movement for shipping safety, would surely have gotten aloft and sent us all some live footage showing the area, but apparently not. Merging two clichés, one about cable tv and the other about big-box stores, I thought: “500 channels, but never what you want”.
Online, of course, there are photos like these from NASA.
Real color photo from NASA. I added the orange line around the breakaway ice island. Source.
False color photo from NASA. Source.
And I did find about two seconds of overhead video on YouTube. It’s about 20 seconds into the video, and most of the rest is talking heads taking sides on whether the event is connected to global warming/climate change. Maybe yes, maybe no, does it really matter if each individual event can be connected? Good for politicians and talk-shows.
In the Antarctic, however, there seems to be quite a clear pattern. Nearly all of the world’s glacier ice, 91%, is located there. An international scientific partnership including the US Geological Survey (and the British Antarctic Survey, with the assistance of the Scott Polar Research Institute and Germany’s Bundesamt fűr Kartographie und Geodäsie) has found that
every ice front in the southern part of the Antarctic Peninsula has been retreating overall from 1947 to 2009, with the most dramatic changes occurring since 1990. The USGS previously documented that the majority of ice fronts on the entire Peninsula have also retreated during the late 20th century and into the early 21st century.
The ice shelves are attached to the continent and already floating, holding in place the Antarctic ice sheet that covers about 98 percent of the Antarctic continent. As the ice shelves break off, it is easier for outlet glaciers and ice streams from the ice sheet to flow into the sea. The transition of that ice from land to the ocean is what raises sea level. [report dated 2/22/10]
Since 1950, total Antarctic ice loss exceeds 9,652 square miles. Temperatures on the Antarctic Peninsula have risen faster than in any other area in the southern hemisphere – a rise that translates to more than five degrees Fahrenheit since the middle of the last century.
This image shows ice-front retreat in part of the southern Antarctic Peninsula from 1947 to 2009. Distance bar may be hard to read: it’s 50 miles in 10 miles increments. USGS scientists are studying coastal and glacier change along the entire Antarctic coastline. The southern portion of the Antarctic Peninsula is one area studied as part of this project, and is summarized in the USGS report, “Coastal-Change and Glaciological Map of the Palmer Land Area, Antarctica: 1947–2009” (map I–2600–C). (Credit: Image courtesy of U.S. Geological Survey). Source.
It is expected that loss of the floating ice shelves will allow the land-based ice to flow faster toward and into the ocean. If the Greenland Ice Sheet were to melt completely, it is estimated that it would add about 23 feet (7 meters) to current sea level. The West Antarctic Ice sheet is believed to be less stable than that covering East Antarctica, because the ice of East Antarctica lies on rock that is above sea level and is thought unlikely to collapse. But the West Antarctic Ice Sheet (WAIS) is on rock below sea level:
“Not just a bit below sea level, it’s 2,000 meters below sea level,” said David Vaughan, a principal investigator with the British Antarctic Survey. “If there was no ice sheet there, this would be deep ocean, deep like the middle of the Atlantic.”
Some scientists have theorized that this makes the WAIS inherently unstable. If the ice sheet retreats beyond a certain point, a positive feedback mechanism should, they say, lead to runaway retreat that would not stop until most of the ice sheet disappears. [Source.]
The Western Antarctic Ice Sheet contains 13% of all the ice on the Antarctic continent, enough to raise current sea levels around 11 feet (3.3 meters). And when the Intergovernmental Panel on Climate Change (IPCC) made its climate change predictions, including the “mid-range projection” (mid-range meaning, not the best-case nor the worst-case scenario) that seas will rise 17 inches (44 centimeters), they did not include what the effects would be, if polar ice sheets began to melt faster than in the decade of 1993-2003. This was done because there wasn’t enough known about ice sheet melting and its change over time. The Antarctic Ice Sheet is 6 miles thick in places, so it’s not easy to know what is going on under it and finding out has only recently seemed important to those who fund such expensive research.
Finally, the aspect that has seemed to many the most frightening about climate change predictions: the unknown potential for interactions between complex systems such as wind currents and ocean currents, which could conceivably multiply foreseen effects. (Or, if we were amazingly lucky, cause them to cancel one another out; but we won’t know until it’s too late to do anything about it.) For example, it’s believed that the melting of Antarctic ice shelves is caused by warmer water flowing up underneath the ice. But this water is not from melting ice; rather it comes from deep within the ocean, and climate change may be making it warmer by one of those unforeseen linkages:
Antarctica is encircled by atmospheric currents that largely insulate it from the rest of Earth’s climate and keep it colder than it otherwise would be. Jenkins’ model showed that these circumpolar currents, sometimes called “Westerlies,” “the Screaming 50s,” or “the Roaring 40s,” actually push surface waters out away from the continent. This results from the Coriolis Force, the byproduct of Earth’s rotation that causes cyclonic systems to turn counterclockwise in the northern hemisphere and clockwise in the southern hemisphere. As surface water is pushed away, warm deep water rises to replace it.
If the atmospheric currents speed up, more water is pulled up. Indeed, observations indicate these atmospheric currents have sped up in recent decades in response to global warming. So increased upwelling seems likely.
[Read more in this article which goes into deeper detail than many accounts of climate research for lay persons. It reports on the 2007 the West Antarctic Links to Sea-Level Estimation (WALSE) international workshop.]
It’s this sort of unforeseen multiplier-effect between two systems (each one of which,by itself, strains our capacity to make accurate mental and statistical models), that makes me think efforts to mitigate, and prepare for, climate change should be at the top of every developed nation’s agenda. Of course it’s not at the top of any nation’s agenda, and won’t be, until the effects are severe—not just “extreme weather” like last week’s flooding and unusual heat waves, but unmistakeable (and irreversible) such as significant rise in sea levels. By then secondary results, such as mass migration of tens of millions trying to flee drought and famine, will be well under way and our primate brains will be where they are most comfortable, dealing with what’s right in front of them. Near-term possibilities are construed concretely, long-term ones abstractly, and the consequences of that upon human action are pretty much as you’d expect. Psychologists even have a name for this, “temporal construal”.
We are told that Homo sapiens mostly evolves culturally now, rather than physically. Yet human cultures in industrial nations are mostly under the control of corporate interests which manufacture and sell us “culture” in a form that serves their ends. Government, also, serves them. If corporations were subject to natural selection we wouldn’t have seen no-strings bailouts for banks and financial institutions, instead there would have been widespread failures. If American culture is poorly adapted for survival in coming conditions, and if the few run it for their short-term gain, then chances for “our” success seem slim. Humans are slippery devils, though, enduring and resourceful. And there are still a few groups of hunter-gatherers and nomads left who may well prove far more resilient than any of our proud nations.
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