Quantcast

Researchers Discover Arctic Warmer Than Anytime in Last 44,000 Years

Climate

By Tim Radford

Good news for Arctic mosses, if not for any other Arctic creatures: little tundra plants that have been buried under the Canadian ice can feel the sunlight for the first time in at least 44,000 years.

The implication is that the Arctic is now, and has been for the last 100 years, warmer than at any time in the last 44,000 years and perhaps for the last 120,000 years.

Researchers have found that the Arctic is warmer now than it was in the early Holocene—the end of the last Ice Age—when the peak summer sunlight was roughly nine percent greater than present day. Photo credit: fruchtzwerg's world/ Flickr

This also means that the Arctic is warmer now than it was in what geologists call the early Holocene, the end of the last Ice Age—when the peak summer sunlight was roughly nine percent greater than it is today, according to Dr. Gifford Miller of the University of Colorado Boulder.

The mosses studied by Dr. Miller, of course, could feel nothing: they were dead. But they could tell a story, all the same.

The Arctic ice cap has been in constant retreat for the last century, and glaciers almost everywhere have been melting: there are fears that the process has begun to accelerate as greenhouse gases concentrate in the atmosphere.

But as the ice recedes, it exposes evidence of the past, preserved over the millennia in the natural deep freeze.

Creating a Timeline of Climate Change

The researchers used a technique called radiocarbon dating to establish that the mosses had been screened from the elements for at least 44,000 to 51,000 years. Since radiocarbon dating is only accurate for about 50,000 years, the mosses could have been buried for perhaps 120,000 years, since the last “interglacial” when the polar regions experienced a natural thaw.

Miller and colleagues report in Geophysical Research Letters that they did their fieldwork on Baffin Island in the Arctic Circle, and measured the radiocarbon ages of the dead mosses in at least four different locations.

They were careful to pick their 145 samples within one meter of the receding ice cap. Since the ice is receding at two or three meters a year, they could be sure the plant tissues had just been exposed that season.

Since the plants could only have taken root in sunlight, they were evidence that the exposed terrain was once free of ice. They became silent witnesses, telling researchers about the changes through time in the frozen North.

“The key piece here is just how unprecedented the warming of Arctic Canada is," said Miller. "This study really says the warming we are seeing is outside any kind of known natural variability, and it has to be due to increased greenhouse gases in the atmosphere.” 

Recent Decades Critical

Since radiocarbon clocks can only tick for so long, the Colorado team used ice cores to provide clues to the climate history of Baffin Island: each winter’s snowfall and summer melt is preserved in the icepack and like the growth rings in a tree provides a calendar of annual change.

The last time temperatures on Baffin Island were as high as today was about 120,000 years ago. About 5,000 years ago, after a mellow period in the early Holocene, the Arctic began to cool again, and stayed cool until the beginning of the last century.

“Although the Arctic has been warming since about 1900, the most significant warming in the region didn’t really start until the 1970s,” said Dr. Miller.

“And it really is in the last 20 years that the warming signal from that region has been just stunning," Miller concluded. "All of Baffin Island is melting, and we expect all of the ice caps to disappear, even if there is no additional warming."

EcoWatch Daily Newsletter

Mr.TinDC / Flickr / CC BY-ND 2.0

By Adda Bjarnadottir, MS

Many nutrients are essential for good health.

Read More Show Less
albedo20 / Flickr

By Pat Thomas

Throughout the U.S., major food brands are trying to get rid of GMO ingredients — not necessarily for the right reasons, but because nearly half of consumers say they avoid them in their food, primarily for health reasons.

But the CEO of Impossible Foods, purveyor of the Impossible Burger, is bucking that trend.

Read More Show Less
Sponsored
People in more than 100 countries are expected to take part in well over 1,000 strikes on May 24 to demand climate action from their governments. @ExtinctionR / Twitter

By Julia Conley

Two months after what was reportedly the largest international climate demonstration ever, young people around the world are expected to make history again on Friday with a second global climate strike.

Read More Show Less
DoneGood

By Cullen Schwarz

Ethical shopping is a somewhat new phenomenon. We're far more familiar with the "tried and tested" methods of doing good, like donating our money or time.

Read More Show Less
Asian elephants frolic in Kaudulla Wewa at Kaudulla National Park in central Sri Lanka. David Stanley / CC BY 2.0

When it comes to saving some of the planet's largest animals, a group of researchers says that old methods of conservation just won't cut it anymore.

Read More Show Less
Sponsored
Pexels

A low-fat diet that prioritizes eating healthier foods like fruits and vegetables each day could lower the risk a woman's risk of dying from breast cancer, according to a multi-decade study published this month.

Read More Show Less
smcgee / Flickr / CC BY-NC 2.0

Several New York City Starbucks exposed customers to a potentially deadly pesticide, two lawsuits filed Tuesday allege.

Read More Show Less
Drinks with plastic straws on sale at London's Borough Market. Susie Adams / Getty Images

The UK government has set a date for a ban on the sale of single use plastics, The Guardian reported Wednesday. From April 2020, the sale of plastic straws, drink stirrers and cotton buds with plastic stems will be prohibited in England.

Read More Show Less