Scientists unravel 8,200-year-old climate riddle

Apr 23, 2005

Palaeoceanographers from the Southampton Oceanography Centre have shed new light on the world’s climate behaviour over 8,200 years ago. In an article published this week in Nature, they demonstrate that a sudden drop in temperature lasting 200 years cannot be used as a template for the modern day threat of rapid climate change.

Lead author, Professor Eelco Rohling, said: ‘This sudden drop in temperature was caused by a flood of fresh water into the Labrador Sea after an ice dam broke. The large influx of fresh surface waters would have slowed the North Atlantic overturning current for about 200 years. Eventually, the current would have re-established to former conditions.

‘This was a one-off event that occurred in a longer-term trend of climate variability. Some scientists have inferred that this cold snap would have had an impact of a global nature. Our analysis suggests the flooding of melt-water was important on a regional North Atlantic scale at the time but was not likely to be important on a global scale.’

The overturning current, often referred to as the Gulf Stream, is responsible for keeping western Europe several degrees warmer than countries at similar latitudes. Scientists fear that global warming would lead to a warmer, wetter climate and that extra fresh water inflow into the North Atlantic would act as a brake on the overturning current resulting in a much cooler climate. Elements of this scenario were dramatised in the film, The Day After Tomorrow, with a knock-on effect that affected the global climate.

Professor Rohling explained: ‘Many scientists are using this 200-year-old cold snap to validate their computer climate models when, in fact, many of the global climate changes around that time seem related to the “underlying” longer-term variability. This confusion has complicated efforts to unravel a pattern of climate variability.

‘This has also had implications for scientists using this history to predict future scenarios of rapid climate change if there was extra fresh water inflow into the North Atlantic.’

The article 'Centennial-scale climate cooling with a sudden cold event around 8,200 years ago' by Eelco J. Rohling and Heiko Pälike is published in Nature on 21 April 2005 (www.doi.org/10.1038/nature03421).

Source: University of Southampton

Explore further: Computer model shows moon's core surrounded by liquid and it's caused by Earth's gravity

add to favorites email to friend print save as pdf

Related Stories

Who gains most from axing the carbon tax – and at what cost?

Jul 18, 2014

When the carbon tax was introduced, there was a lot of discussion about winners and losers. The Labor government limited the number of businesses that had to pay the tax, while it also gave carbon tax relief to large carbon emitters and large energy users. There were tax ...

Australia abolishes divisive carbon tax

Jul 17, 2014

Australia on Thursday axed a divisive carbon tax after years of vexed political debate, in a move criticised as regressive and out of step with the rest of the world.

Recommended for you

Comet Jacques makes a 'questionable' appearance

16 hours ago

What an awesome photo! Italian amateur astronomer Rolando Ligustri nailed it earlier today using a remote telescope in New Mexico and wide-field 4-inch (106 mm) refractor. Currently the brightest comet in ...

Image: Our flocculent neighbour, the spiral galaxy M33

16 hours ago

The spiral galaxy M33, also known as the Triangulum Galaxy, is one of our closest cosmic neighbours, just three million light-years away. Home to some forty billion stars, it is the third largest in the ...

Titan offers clues to atmospheres of hazy planets

16 hours ago

When hazy planets pass across the face of their star, a curious thing happens. Astronomers are not able to see any changes in the range of light coming from the star and planet system.

Having fun with the equation of time

17 hours ago

If you're like us, you might've looked at a globe of the Earth in elementary school long before the days of Google Earth and wondered just what that strange looking figure eight thing on its side was.

User comments : 0