News24

Arctic had extreme warm periods

2012-06-22 08:26

Washington - An international team of scientists said that the Arctic went through ice-free periods of extreme warmth over the past 2.8 million years, based on a new analysis of deep sediment in Russia.

The team led by Martin Melles of the University of Cologne, Germany, drilled into an iced-over lake formed by a meteorite impact on the Chukchi Peninsula in Siberia for the longest sediment core ever collected in the terrestrial Arctic.

Since the meteorite struck an area of Lake El'gygytgyn that was not eroded by glaciers, the sediment record reaches back nearly 30 times further in time than ice cores from Greenland that cover the past 110 000 years.

The sediment reveals periods of extreme warmth that show the polar regions are much more vulnerable to change than previously thought, and are difficult to explain by greenhouse gases alone, said the study in the journal Science.

Scientists have long known that the Arctic went through climate cycles, but the latest research shows some of these warm phases were "exceptional", with temperatures 4°C to 5°C warmer and 30cm wetter than during normal interglacials, the study said.

Sea level rise


Two of these "super-interglacials" happened about 400 000 years ago and 1.1 million years ago, and the data suggests it was virtually impossible for Greenland's ice sheet to have existed in its present form at those times.

But just what caused these extreme changes remains a mystery.

Since some of the Arctic changes mirror variations in the Antarctic discovered by previous studies, events at one pole may have triggered events at the other, the researchers said.

One possibility is that reduced ice cover in Antarctica led to less cold bottom water mass in the northern Pacific, triggering warmer surface waters, higher temperatures and more precipitation.

Another is that the dissolving Antarctic ice sheet led to global sea level rise that sent warm water rushing into the Arctic Ocean, the study said.

Co-authors of the study included experts from the University of Massachusetts and the Far East Branch of the Russian Academy of Sciences.

Comments
  • Detective.Kruger - 2012-06-22 08:40

    So does this mean Global warming is a load of poo

      Stirrer - 2012-06-22 09:47

      Yes.

      billyboy6 - 2012-06-22 11:43

      Not a chance, in fact it proves it. Your question is not if global warming exists but if man is a serious contributory factor given there are past experiences of it happening. The truth is that it is happening and will have devastating effects on life as we know it and therefore we should do all we can to minimize it

      ernst.j.joubert - 2012-06-22 14:11

      @Stirrer and Detective: Arguing that past climatic changes (high arctic temperatures etc.)disproves manmade global warming is like arguing that man cannot start bush fires because, before man, bush fires always started due to natural causes. Hence, the conclusion that you are deriving from the article is totally wrong.

      peter.krummeck.3 - 2012-06-22 14:36

      @ Dt.Kruger: how simplistic can you get? Just because it happened before doesn't mean global warming won't make it happen again - a whole lot faster! And 'poo' - especially verbal, won't help.

  • gungets.tuft - 2012-06-22 08:49

    How about cyclical warming and cooling .... all the non-IPCC scientists have been saying so but have been branded as heretics and denialists. Can't wait for the ad-hominem attacks to start from the AGW supporters.

      ernst.j.joubert - 2012-06-22 14:09

      @gungets: "How about cyclical warming and cooling..." Arguing that past climatic changes disproves manmade global warming is like arguing that man cannot start bush fires because, before man, bush fires always started due to natural causes. Hence, past climatic changes show that our climate is sensitive to forcings (changes in greenhouse gas concentrations etc.) and so it actually proves that man can have a significant effect.

      gungets.tuft - 2012-06-22 14:47

      Ernst - it proves there were, and are, cycles. A great many "scientists" refuse to acknowledge the effect of natural cycles in the warming of the 60's to the late 90's. A warming that observations say is over. Agree completely that man can have an influence, but if man stopped producing co2 tomorrow, and methane and the other so-called greenhouse gasses, the natural cycle will continue. Man influence is tiny in the GW debate, massive in the pollution and exploitation debate. But, when AGW is kicked into the corner, as it will be, then so will the sustainability debate that the GW theorists have hijacked. They will have missed the opportunity to attack the real evil. I agree 100% with moving to alternative energy sources, away from fossil fuels etc, I just want it for a different reason, but the AGW reason is going to kill that sustainability debate. Watch.

      ernst.j.joubert - 2012-06-22 16:07

      @gungets: Increasing greenhouse gas concentrations are going to have an effect on the climate. You cannot explain this paramount fact away. It is incorrect to say that because these increases, caused by man, are small they are insignificant. Example: Cyanide in trace quantities is lethal. So things in small concentrations can have very big effects.

  • bam.boo.5621 - 2012-06-22 08:54

    Global Warming is just a conspiracy to put a stop to industrialisation and forcing countries to become economic dependent on other more powerful countries. There are no hard facts that support the theory of global warming.

      Tony Lapson - 2012-06-22 12:32

      Let me put you in a room with 20 people 1 smoker and 1 diesel truck.

      bam.boo.5621 - 2012-06-22 12:40

      We are talking about global warming not localised warming. There are more effective and efficient ways of industrialisation these days. These guys want to cease all industrialisation activities.

      ernst.j.joubert - 2012-06-22 14:15

      bam.boo: "There are no hard facts that support the theory of global warming." Really? 98% of climate scientists, actively publishing in peer reviewed journals, have strong evidence that rising concentrations of greenhouse gasses in the atmosphere (due to human activity) is rapidly changing the climate. "There are no hard facts that support the theory of global warming. "

      ernst.j.joubert - 2012-06-22 14:21

      @ bam.boo: "Global Warming is just a conspiracy to put a stop to industrialisation and forcing countries to become economic dependent on other more powerful countries." Actually, addressing manmade global warming by aggressively persuing renewables like wind and solar will make countries more energy independent (would not need to suck up to OPEC) and so they will be far less vulnerable than they are under the current system.

      Tony Lapson - 2012-06-22 15:26

      I wasn't talking about localized global warming, Some people just need very over-simplified examples.

      robin.stobbs.9 - 2012-06-23 18:33

      Bollocks Ernst - 5 out of 6 film stars use Lux. Come on there. Do some objective and up-to-date reading and open your closed mindset.

  • flyswat - 2012-06-22 10:38

    Ha! Suck on that, global warming idiots! Define normal earth temperature and normal weather patterns. How would we know? Humans have not been around long enough, much less recording things for long enough to know. The evidence is in the earth itself.

      Tony Lapson - 2012-06-22 12:27

      Clearly either religious, misinformed or merely stupid.

      ernst.j.joubert - 2012-06-22 14:25

      @Flyswat: Arguing that past climatic changes disproves manmade global warming is like arguing that man cannot start bush fires because, before man, bush fires always started due to natural causes. Did you even read the article? The article doesnt disprove AGW. The article shows that the climate is sensitive to disturbances. The conclusions you are deriving is totally wrong.

      flyswat - 2012-06-23 14:36

      @Tony One needs to be really stupid to be brainwashed. To be a religious person means you are brainwashed. I am athiest, sorry. On the other hand, you seem to have fallen into the global warming brainwashing cauldron...shame! Funnily enough, I'm not misinformed either. High levels of CO2 is needed for plants to thrive. Humans need plants for survival in many ways. Lack of CO2 is the quickest way to kill the earth. If you are all worried about desertification, the problem is not CO2, but overpopulation and the raping of arable land by misinformed masses.

      ernst.j.joubert - 2012-06-23 16:22

      @Flyswat: "Funnily enough, I'm not misinformed either........" To the contrary you are totally misinformed. Regurgitating the classic climate denialist argument that more CO2 is actually a good thing, led me to this conclusion. The issue is rising concentrations of CO2 over natural levels, caused by the burning of fossil feuls and deforrestation. Before the industrial revolution, CO2 concentration was 280ppm. Today, this level stands at 395ppm. It is incorrect to believe that because plants need CO2, more CO2 is a good thing. This is the same as arguing that because humans need food, they can eat as much as they like without any negative consequences (like dying from obesity).

      robin.stobbs.9 - 2012-06-24 16:51

      So tell us Ernst - what IS the natural level for CO2 and for how long have you been measuring it?

      ernst.j.joubert - 2012-06-24 17:05

      @Robin: You are not in a posision to ask questions as you deny the basic fact that C02 is a greenhouse gas.

      ernst.j.joubert - 2012-06-24 17:37

      @Robin: "....what IS the natural level for CO2 and......" "Natural" C02 levels refer to levels that man has become use to over hundreds of thousands of years. It is these levels that have enabled man to have a relatively stable climate and has allowed us to florish. These levels have been kept relatively stable by natural processes that absorb and release C02. "...... for how long have you been measuring it....." Scientists can estimate the C02 levels that existed at various times in earth's history by drilling into ice cores. Unnatural C02: Refers to the additional C02 that is added to the natural levels by digging up carbon (that has been stored underground for billions of years) and burning it. It is projected that if no action is taken, C02 levels will rise to 800ppm (from 280ppm before the industrial revolution); levels that existed millions of years ago. I would just like to ask you a question: DO you think it is wise to go back to conditions that existed when dinosaurs ruled the earth in a matter of a centuary?

  • colin.ashby.35 - 2012-06-22 10:42

    impossible. the earth is only 6000 years old. just some scientits trying to make a name for them selves.most scientits have huge egos and they need to be stroked.

      Stirrer - 2012-06-22 10:47

      "most scientits ... need to be stroked" - a Freudian slip?

      ever.ryman - 2012-06-22 11:04

      6000 years old? You are joking, right????

      colin.ashby.35 - 2012-06-22 11:12

      @ Stirrer..no, not a slip when its done twice...lol @ever.ryman....no

      Tony Lapson - 2012-06-22 12:14

      Lololololololololololololololololololksksnebzodlshevaudidownavaodmxnjsowh DAFAQ DID I JUST READ?!?!

      zane.zeiler - 2012-06-22 12:21

      Good lord man! Read a book or something!

      ever.ryman - 2012-06-22 13:04

      Hondbyt-trouble is he's reading the wrong book!

      robin.stobbs.9 - 2012-06-24 16:50

      @ Colin - I think you need to extract your head from the mud and do some scientific reading. If you find the right book the words are not too complicated and easily understood!

  • iwan.scott - 2012-06-22 21:02

    Proof of poleshift!?

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