Ancient Greenland was green. New Danish research has shown that it was covered in conifer forest and, like southern Sweden today, had a relatively mild climate. Eske Willerslev, a professor at Copenhagen University, has analysed the world’s oldest DNA, preserved under the kilometre-thick icecap. The DNA is likely close to half a million years old, and the research is painting a picture which is overturning all previous assumptions about biological life and the climate in Greenland. The results have just been published in the prestigious scientific journal Science.
Ten percent of the Earth’s surface has been covered with ice for thousands of years. No one knows what lies beneath the kilometre-deep icecaps. These are the earth’s unknown and unexplored regions. But some have begun the exploration. Several projects under Danish leadership have been drilling through the icecap on Greenland, and collected complete columns of ice all the way from the top to the bottom. The ice has annual layers and is a frozen archive of the world’s climate.
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At the DYE-3 drilling-site, the ice is ‘only’ two kilometres thick, and here the DNA-material was so well preserved that Eske Willerslev could extract genetic traces of a long list of plants and insects and thereby reconstruct ancient plant and animal life.
“This genetic material presents a biological environment, which is completely different to what we see today.” he says. “We have found grain, pine, yew and alder. These correspond to the landscapes we find in Eastern Canada and in the Swedish forests today. The trees provide a backdrop from which we can also ascertain the climate since each species has its own temperature requirements. The yew trees reveal that the temperature during the winter could not have been lower than minus 17 degrees Celsius, and the presence of other trees shows that summer temperatures were at least 10 degrees”.
The research results are the first direct proof that there was forest in southern Greenland. Furthermore Willerslev found genetic traces of insects such as butterflies, moths, flies and beetles. But when was that" According to most scientific theories to date, all of southern Greenland and most of the northern part were ice-free during the last interglacial period 125,000 years ago, when the climate was 5 degrees warmer than the interglacial period we currently live in.
Again. See the Antarctic post below.
HOWEVER! This is for the Greenland was never green twits: IT HAS BEEN MULTIPLE TIMES, DAMNIT. That includes the Eocene, the last interglacial and the Medieval Warm Period.
I have a confession - I'm one of those "Greenland was never green" twits. Whenever I argue with my skeptic friends who tell me 'Greenland was green', I cite the ice shelf which has been there for thousands of years. So in one sense, this new study confirms that - the ice shelf is at least 450,000 years old - well before Erik the Red named the island.
ReplyDeleteIn terms of the global warming debate, I recommend reading what the authors are actually saying about their own study. The study connects past warming to natural variations in Earth's orbit—obliquity, or how tilted the planet is in relation to the sun. Author Martin Sharp points out "One could argue that this shows that natural forcing could account for the current warm conditions, but the current orbital configuration does not support this, even when other natural forcings are taken into account." In other words, their study "really has nothing to say about the mechanisms driving the current warming."
According to author Eske Willerslev, the Greenland ice shelf "has not contributed to global sea level rise during the last interglacial. Importantly, it does not mean that we should not be worried about future global warming as the sea level rise of five to six meters during the last interglacial must have come from somewhere."
Finally, Martin Sharp warns the study "does not prove the current global warming trend is not human induced". If anything, "we may be heading for even bigger temperature increases than we previously thought".
Hola, JC.
ReplyDeleteThe climate fluctuates quite a bit. Yes, the authors are arguing that the ice cap has been persistant over a very long period even during warmer periods. However, just because the ice cap has been present doesn't mean that there hasn't been forest nigh on near the edges of said cap. There are points in SoAm where there is forest just like that. There were points in the Alps where the glaciers plowed through those forests there during the Little Ice Age.
The Milankovitch Cycles are still having an impact, yes, but please note that I am emphatically not a Global Warming Denier. I just think it serves no one any good to make up cruft when the facts are very self evident. We have a responsibility to prevent another global cooking...aka Permian Extinction. :)
Welcome to my blog, btw.
Hmm, in that case, I don't see any point where we actually disagree. That was a short discussion! :-)
ReplyDeleteDAMNIT! Vehement agreement is so frakkin evil when it comes to discussions. ;)
ReplyDelete