PERHAPS you’ve seen Al Gore’s 2006 documentary An Inconvenient Truth, with its memorable images of deep blue rivers of meltwater flowing across the Greenland icecap before plunging into terrifying holes that bring to mind Coleridge’s line about how ‘Alph the sacred river ran / Though caverns measureless to man’.
Where this meltwater goes, nobody knows, or not in detail at any rate. But we do know that a lot of it eventually percolates into the ocean, where it contributes to sea-level rise.
Global warming is a very controversial topic and the fact that I saw the effect of the warming ocean and rising sea levels for myself made me very conscious of it. There are islands like Kiribati which are suffering massive land loss every year — at an incredible rate actually. It’s the warming of the Arctic that cause more icebergs and ice sheets to melt and massive amounts of water pour into the ocean causing the levels around the world to rise. I saw a documentary where the prime minister of the Pacific tropical islands of Kiribati went to the Arctic to see where all the water was coming from — he was convinced of global warming and was urging people to keep in mind the impacts of climate change. For him and his people it was very real!
Although global temperatures have warmed by only just over a degree Celsius since the Industrial Revolution, so far, the warming is more concentrated in Arctic and Antarctic latitudes, and Greenland is now between two and four degrees Celsius warmer than it used to be in the mid-nineteenth century. Winters are in places up to ten degrees warmer, which has implications for the generation of sea ice. Overall, this warming has had very real and visible effects including the shrinkage of Arctic Sea ice and the almost total disappearance of the Jakobshavn Glacier near Ilulissat, a famous glacier which used to be one of the largest in the Arctic.
Where the Jakobshavn Glacier used to be in 1850, there is now just a huge fjord extending more than 50 kilometres inland. This is a very dramatic event to have happened on such a short geological timescale and it happened, partly, because of a phenomenon called ice-cliff instability. Normally, the ice of Greenland and Antarctica taper down to the sea, or to dry land short of the sea. Actual ice cliffs much more than 100 metres high aren’t stable and collapse under their own weight, creating another cliff behind — and so on.
So, the whole icecap doesn’t have to melt right where it is, in order to wind up in the sea as additional water promoting sea level rise. All that’s required is for the tapering edges to melt away, and then the thick ice of the interior will start falling down around the edges, in great chunks. The fallen ice will help to prop up the ice cliff behind, just like the tapering ice that used to be there in the same place. But if the broken ice falls into an area that is now open sea, the sea will quickly wash the fallen and broken ice away, exposing a new, bare, cliff face to crumble some more. This is a significant worry wherever the bedrock level under the ice cap is below sea level — which is actually the case for much of Greenland and Antarctica. Thus, a massive deep-frozen icecap could collapse quite quickly and be replaced by open sea, something that is also called the Jakobshavn effect.
Along with the Jakobshavn effect, in 2012, melting ice was recorded almost everywhere over the Greenland ice sheet in mid-summer, that year. Normally, melting of this kind is only seen around the tapering edges of the ice sheet and not in the thick, deep-frozen interior. In other words, the icecap is threatened not only by melting at the edges and subsequent crumbling due to the Jakobshavn effect, but also by actual melting-in-place. When these effects are combined with various other phenomena that also undermine the ice sheet, such as the lubrication of the bottom and cracking of the ice caused by the weight of the plunging water (denser than the ice, of course, and capable of acting like a wedge in a crevasse), it leads to a worrying picture. Estimates of how quickly the Greenland ice cap could break up melt in the face of sustained warm temperatures are constantly being revised in the more-quickly direction.
More recently, in 2021, rain was recorded even at the highest point on the Greenland icecap, something that has never been seen before. Of course, rain has a powerful melting effect on ice and snow. Even if rain only melts the snow on top, it exposes the transparent ice below, which often looks deep blue or black, and which absorbs the sun’s rays in much the same way that open seawater does.
I did see the evidence of ice melt in exhibitions in several of the museums I visited around Greenland. The ice melt is guessed at being in the trillions of tonnes every year. There was concern expressed by the locals when I asked them about it — it was more that there was not only a loss of land but also cultural practices like Arctic fishing and hunting. At the museum in Nuuk I would visit the next day, I saw how the Inuit would cut holes in the ice and put down a rod with 15 hooks attached to it. Fish used to be abundant in Greenland’s waters, and no one went hungry after a fishing trip. More often than not, now, they don’t catch anything.
Go Greenland is available on this website, a-maverick.com.
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