Germany’s once prestigious Alfred Wegener Institute has just issued a stunning press release informing the whole world about a new ground-breaking study showing that we do not need to expect the same climate change today that the earth saw during the last ICE AGE – because, you see, the pre-conditions back then were different.
Really! You don’t say! Gee, who would have ever thunk it. How much money was spent to find out that piece of what has long been obvious to everyone else?
And they wonder why our respect for their multi-billion dollar field, where 97% of their models have been dead wrong, has all but vanished.
AWI climate scientist Gerrit Lohmann summarizes:
There are apparently some situations in which the climate system is more resistant to change while in others the system tends toward strong fluctuations. In terms of the Earth’s history, we are currently in one of the climate system’s more stable phases. The preconditions which gave rise to rapid temperature changes during the last ice age do not exist today.”
Here is the entire press release:
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Bremerhaven, Germany, August 19th, 2014. Over the past one hundred thousand years cold temperatures largely prevailed over the planet in what is known as the last ice age. However, the cold period was repeatedly interrupted by much warmer climate conditions. Scientists have long attempted to find out why these drastic temperature jumps of up to ten degrees took place in the far northern latitudes within just a few decades. Now, for the first time, a group of researchers at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), have been able to reconstruct these climate changes during the last ice age using a series of model simulations. The surprising finding is that minor variations in the ice sheet size can be sufficient to trigger abrupt climate changes. The new study was published online in the scientific journal Nature last week and will be appearing in the 21 August print issue.
During the last ice age a large part of North America was covered with a massive ice sheet up to 3km thick. The water stored in this ice sheet is part of the reason why the sea level was then about 120 meters lower than today. Young Chinese scientist Xu Zhang, lead author of the study who undertook his PhD at the Alfred Wegener Institute, explains. “The rapid climate changes known in the scientific world as Dansgaard-Oeschger events were limited to a period of time from 110,000 to 23,000 years before present. The abrupt climate changes did not take place at the extreme low sea levels, corresponding to the time of maximum glaciation 20,000 years ago, nor at high sea levels such as those prevailing today – they occurred during periods of intermediate ice volume and intermediate sea levels.” The results presented by the AWI researchers can explain the history of climate changes during glacial periods, comparing simulated model data with that retrieved from ice cores and marine sediments.
How rapid temperature changes might have occurred during times when the Northern Hemisphere ice sheets were at intermediate sizes (see graphics below)
During the cold stadial periods of the last ice age, massive ice sheets covered northern parts of North America and Europe. Strong westerly winds drove the Arctic sea ice southward, even as far as the French coast. Since the extended ice cover over the North Atlantic prevented the exchange of heat between the atmosphere and the ocean, the strong driving forces for the ocean currents that prevail today were lacking. Ocean circulation, which is a powerful “conveyor belt” in the world’s oceans, was thus much weaker than at present, and consequently transported less heat to northern regions.
During the extended cold phases the ice sheets continued to thicken. When higher ice sheets prevailed over North America, typical in periods of intermediate sea levels, the prevailing westerly winds split into two branches. The major wind field ran to the north of the so-called Laurentide Ice Sheet and ensured that the sea ice boundary off the European coast shifted to the north. Ice-free seas permit heat exchange to take place between the atmosphere and the ocean. At the same time, the southern branch of the northwesterly winds drove warmer water into the ice-free areas of the northeast Atlantic and thus amplified the transportation of heat to the north. The modified conditions stimulated enhanced circulation in the ocean. Consequently, a thicker Laurentide Ice Sheet over North America resulted in increased ocean circulation and therefore greater transportation of heat to the north. The climate in the Northern Hemisphere became dramatically warmer within a few decades until, due to the retreat of the glaciers over North America and the renewed change in wind conditions, it began to cool off again.
“Using the simulations performed with our climate model, we were able to demonstrate that the climate system can respond to small changes with abrupt climate swings,” explains Professor Gerrit Lohmann, leader of the Paleoclimate Dynamics group at the Alfred Wegener Institute, Germany. In doing so he illustrates the new study’s significance with regards to contemporary climate change. “At medium sea levels, powerful forces, such as the dramatic acceleration of polar ice cap melting, are not necessary to result in abrupt climate shifts and associated drastic temperature changes.”
At present, the extent of Arctic sea ice is far less than during the last glacial period. The Laurentide Ice Sheet, the major driving force for ocean circulation during the glacials, has also disappeared. Climate changes following the pattern of the last ice age are therefore not to be anticipated under today’s conditions.
“There are apparently some situations in which the climate system is more resistant to change while in others the system tends toward strong fluctuations,” summarises Gerrit Lohmann. “In terms of the Earth’s history, we are currently in one of the climate system’s more stable phases. The preconditions which gave rise to rapid temperature changes during the last ice age do not exist today. But this does not mean that sudden climate changes can be excluded in the future.”
Notes for Editors:
The original paper was published in Nature under the following title :
Xu Zhang, Gerrit Lohmann, Gregor Knorr, Conor Purcell:Abrupt glacial climate shifts controlled by ice sheet changes. Nature, DOI: 10.1038/nature13592
Your scientific contact persons at the Alfred Wegener Institute are:
- Xu Zhang (tel.: +49 471 4831-1880; e-mail: Xu.Zhang(at)awi.de).
- Prof. Dr. Gerrit Lohmann (tel.: +49 471 4831-1758, e-mail: Gerrit.Lohmann(at)awi.de)
- Dr. Gregor Knorr (tel.: +49 471 4831-1769, e-mail: Gregor.Knorr(at)awi.de)
Your contact person in the Dept. of Communications and Media Relations is Sina Löschke ( tel. +49 471 4831-2008; e-mail: medien@awi.de).
Historian Geoffrey Parker wrote “Global Crisis: war, climate change and catastrophe in the seventeenth century.” He details how extreme weather caused droughts, famines and wars, resulting in the world’s population declining by about one-third during that century.
Yes, climate change can happen naturally.
I think your sarcasm is warranted. The main points of this article do not add much beyond an undergraduate course in Quaternary Geology.
I formerly subscribed to Science Daily via my newsfeed. So many of the papers in physics, chemistry, biology and Earth science were just rehashes of stuff I studied in college or with my wife when she did her degree in biology that I unsubscribed in disgust.
The reason for this state of affairs is obvious: college teachers have to publish. And the journals have to find papers to keep the presses rolling.
So we get lots of rehashing of old stuff. And lots of alarmism.
I cancelled my subscription to Science and my membership of the AAAS for the same reason.
Google Scholar has lots of pre-prints and there are now so many open journals and science blogs that I can keep up without wading through a lot of crap.
Sounds to me as though the term “tipping point” has become unfashionable. Here’s a guy who finally found (modelled) evidence for a tipping point and hasn’t taken credit for it.
“Your comment is awaiting moderation.” Hey Pierre – just what triggers this trip to purgatory? Your system sure takes offense readily!
Sorry for the delay. To be honest I’m still trying to figure that out. You’re approved for commenting, but for whatever reason you (and other readers) still get snagged from time to time.
“Using the simulations performed with our climate model, we were able to demonstrate…”
Of course not. Model outputs do not contitute evidence, so not demonstration is possible. At most, they can offer a somewhat compelling conjecture.
Well, that’s the second exciting new piece of climate science I learned this week.
The other was that as rivers and streams dry up due to global warming, fish are threatened. No, really!! http://news.osu.edu/news/2014/08/18/climate-change-will-threaten-fish-by-drying-out-southwest-us-streams-study-predicts/
Are academic standards changing?
Just a quick reminder: wherever you are, we’re paying for this kind of thing each and every day and there’s no predicting when, or even if, it will end.
http://news.bbc.co.uk/1/hi/scotland/highlands_and_islands/8010513.stm
“He wrote of arctic ice expanding further south and of reports of Inuit people arriving on Orkney between 1690 and 1728. One was said to have paddled down the River Don in Aberdeen. ”
I’m thinking that the sea ice at least was quite extensive. Don’t sea the inuit crossing a couple of thousand miles of open ocean in their Kayaks.
They tested their model first on modern climate, and after it reproduced the last 100 years perfectly…
…oh wait.
[…] https://notrickszone.com/2014/08/19/shock-leading-climate-institute-just-discovers-that-ice-age-clima… […]
what precoditions are missing? The Sun is still around, the oceans are still with us, CO2 in varying amounts are here, we are in a warm period as before other ice ages arrived….hmm!