Rapid changes in Greenland climate last 5,000 years, study finds

June 1, 2011 By Tom Simons
From left, William D'Andrea, Sherilyn Fritz and Fritz's former UNL Ph.D. student Frank Aebly at the edge of the Greenland Ice Sheet in July 2002, about 25 miles east of the lakes that were reported on in PNAS.

(PhysOrg.com) -- Abrupt average temperature changes of as much as 4 or 5 degrees Celsius over a few decades may have profoundly affected human civilization for cultures that occupied western Greenland over the past 5,000 years.

Those are the findings of a study published in the May 30-June 3 online edition of the by a group of scientists that included Sherilyn Fritz of the University of Nebraska-Lincoln.

Using a new technique that measures the qualities of haptophytes (salt-loving microscopic plants), the scientists studied carbon-dated recovered from the beds of two saline lakes near Kangerlussuaq, West Greenland, an area north of the two major medieval Viking (Norse) settlements.

Haptophytes are common in the ocean and they produce group of compounds called alkenones, a type of lipid. Like the fats in human diets, they're saturated and unsaturated, and the level of saturation depends on . Haptophytes have been used for decades to infer temperature variation in oceans, but only in the last 10 years or so have scientists known that they also occur in salt lakes. The study detailed in PNAS was part of the development of the use of alkenones in researching temperature history in salt lakes. The technique allowed the scientists for the first time to fine-tune their knowledge of climate change in West Greenland -- and they found some dramatic changes.

Lake E, one of the Greenland salt lakes studied in the PNAS paper (the other is Braya So).

The fossil organisms revealed a succession of temperature shifts that roughly coincide with changes in human occupation of the area, including the Saqqaq people (4,500 to 2,800 years ago), the Dorset (2,800-2,000 years ago), the Norse (1,000-550 years ago) and the Inuit (800 years ago to present).

"The research is important because the study has basically described and quantified the temperature variation during the last 5,000 years in this area of West Greenland which has had a fairly rich cultural history over much of that time period," said Fritz, George Holmes university professor of earth and atmospheric sciences.

"Some of the changes are quite rapid and fairly large. There's a temperature drop of about 4 degrees Celsius starting about 800 years ago when the Norse were still there, but the reconstruction suggests that within 80 years, temperature dropped 4 degrees during summer months and stayed quite low, so it's quite a large fluctuation. And there are other periods when temperature change was quite rapid and substantial, in the order of 4 to 5 degrees Celsius."

Thanks in large part to ice cores recovered from the massive ice sheet that covers most of Greenland, scientists have long had a good understanding of hemispheric- and millennial-scale climate variability in the North Atlantic and Europe over the past several thousand years. They've also known that was happening in West Greenland, including the areas where the Vikings settled, but until now, they haven't been able to quantify the specific conditions.

The study's lead author is William J. D'Andrea, a postdoctoral fellow at the University of Massachusetts in Amherst. D'Andrea began the research during field seasons from 2001 to 2003 as his master's thesis project with Fritz at UNL, and went on to earn a doctorate studying with organic geochemist Yongsong Huang at Brown University, where he completed the study. Huang and N. John Anderson of Loughborough University in the United Kingdom are also co-authors of the PNAS paper.

Explore further: Climate played big role in Vikings' disappearance from Greenland

Related Stories

Ice cores map dynamics of sudden climate changes

June 19, 2008

New, extremely detailed data from investigations of ice cores from Greenland show that the climate shifted very suddenly and changed fundamentally during quite few years when the ice age ended. Researchers from the Niels ...

As Greenland melts

October 19, 2009

Not that long ago - the blink of a geologic eye - global temperatures were so warm that ice on Greenland could have been hard to come by. Today, the largest island in the world is covered with ice 1.6 miles thick. Even so, ...

Recommended for you

Study finds pollution is deadlier than war, disaster, hunger

October 20, 2017

Environmental pollution—from filthy air to contaminated water—is killing more people every year than all war and violence in the world. More than smoking, hunger or natural disasters. More than AIDS, tuberculosis and ...

Carbon coating gives biochar its garden-greening power

October 20, 2017

For more than 100 years, biochar, a carbon-rich, charcoal-like substance made from oxygen-deprived plant or other organic matter, has both delighted and puzzled scientists. As a soil additive, biochar can store carbon and ...

Cool roofs have water saving benefits too

October 20, 2017

The energy and climate benefits of cool roofs have been well established: By reflecting rather than absorbing the sun's energy, light-colored roofs keep buildings, cities, and even the entire planet cooler. Now a new study ...


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.