Sudden climate change varies from country to country

November 1, 2013 by Harriet Jarlett, PlanetEarth Online
Sudden climate change varies from country to country

Different countries may have recovered faster than others as the last Ice Age ended, new research shows.

The study, published in Geology, shows that 12,100 years ago, as the last ended, Germany's climate began to recover 120 years before Norway's climate.

The team studied Lake Meerfelder Maar in Germany, which has clear sediment layers representing different seasons.

"The annually laminated sediments give us a really nice record of since the last ice age," explains Dr Christine Lane of the University of Oxford, lead author on the study. "They form on a seasonal basis, like tree rings, so you can count back and determine when they formed."

Lane and her colleagues, from Oxford, GFZ Potsdam and Royal Holloway, University of London, found a small band of in the layers, from an eruption of Iceland's Katla volcano.

This ash could be used as a time reference point. Since they knew when the eruption occurred, they could date the layers much more accurately than if they just counted back from the surface.

"The ash layer is found 100 layers, or 100 years, before we see a shift in climate that took place in the Younger Dryas – a 1000 year cold period at the end of the last Ice Age. It has also been found in Norway, at Lake Kråkenes, but there we see the same transition takes place 20 years after the ash layer," says Lane.

Sudden climate change varies from country to country
A microscopic image of the annually-layered sediments from Meerfelder Maar. Each light-dark couplet represents a year and allows researchers to explore environmental changes down to seasonal scales.

The shift in climate is believed to represent the gradual recession of the polar front - the boundary where cool air from the poles and warm air from the tropics meets - as Europe warmed.

Lane says that discovering the 120-year offset between the two sites proves how important it is for researchers not to assume such events must have happened at the same time everywhere.

"We can't assume climatic changes are synchronous worldwide, or even continent-wide. Some regions might feel changes in climate at different times," says Lane. "Climate models need to be able to handle subtle complexities in timing to give accurate future predictions."

Explore further: Doubt over 'volcanic winter' after Toba super-eruption

More information: Lane, C. et al. (2013) Volcanic ash reveals time-transgressive abrupt climate change during the Younger Dryas, Geology.

Related Stories

Doubt over 'volcanic winter' after Toba super-eruption

May 1, 2013

( —New research from Oxford University casts doubt on the theory that the Mount Toba super-eruption, which took place at the Indonesian island of Sumatra 75,000 years ago, could have plunged the Earth into a volcanic ...

West Antarctic ice sheet formed earlier than thought

October 9, 2013

About 34 million years ago, Earth transitioned from a warm "greenhouse" climate to a cold "icehouse" climate, marking the transition between the Eocene and Oligocene epochs. This transition has been associated with the formation ...

Tackling an Ice Age mystery

September 5, 2013

In the northern hemisphere, ice sheets ebb and flow in 100,000-year cycles, driven by varying amounts of sunlight falling on Earth's surface as its orbit and orientation toward the sun changes. But astronomical variations ...

Recommended for you

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

4 / 5 (4) Nov 01, 2013
Could the difference be because the ice melted later in Norway than in Germany? If the ice melted from south to north it would seem reasonable for the north to stay cold longer.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.