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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."

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A volcano erupts on New Zealand's Whakaari/White Island on Dec. 9, 2019. Michael Schade / Twitter

A powerful volcano on Monday rocked an uninhabited island frequented by tourists about 30 miles off New Zealand's coast. Authorities have confirmed that five people died. They expect that number to rise as some are missing and police officials issued a statement that flights around the islands revealed "no signs of life had been seen at any point,", as The Guardian reported.

"Based on the information we have, we do not believe there are any survivors on the island," the police said in their official statement. "Police is working urgently to confirm the exact number of those who have died, further to the five confirmed deceased already."

The eruption happened on New Zealand's Whakaari/White Island, an islet jutting out of the Bay of Plenty, off the country's North Island. The island is privately owned and is typically visited for day-trips by thousands of tourists every year, according to The New York Times.

Michael Schade / Twitter

At the time of the eruption on Monday, about 50 passengers from the Ovation of Seas were on the island, including more than 30 who were part of a Royal Caribbean cruise trip, according to CNN. Twenty-three people, including the five dead, were evacuated from the island.

The eruption occurred at 2:11 pm local time on Monday, as footage from a crater camera owned and operated by GeoNet, New Zealand's geological hazards agency, shows. The camera also shows dozens of people walking near the rim as white smoke billows just before the eruption, according to Reuters.

Police were unable to reach the island because searing white ash posed imminent danger to rescue workers, said John Tims, New Zealand's deputy police commissioner, as he stood next to Prime Minister Jacinda Ardern in a press conference, as The New York Times reported. Tims said rescue workers would assess the safety of approaching the island on Tuesday morning. "We know the urgency to go back to the island," he told reporters.

"The physical environment is unsafe for us to return to the island," Tims added, as CNN reported. "It's important that we consider the health and safety of rescuers, so we're taking advice from experts going forward."

Authorities have had no communication with anyone on the island. They are frantically working to identify how many people remain and who they are, according to CNN.

Geologists said the eruption is not unexpected and some questioned why the island is open to tourism.

"The volcano has been restless for a few weeks, resulting in the raising of the alert level, so that this eruption is not really a surprise," said Bill McGuire, emeritus professor of geophysical and climate hazards at University College London, as The Guardian reported.

"White Island has been a disaster waiting to happen for many years," said Raymond Cas, emeritus professor at Monash University's school of earth, atmosphere and environment, as The Guardian reported. "Having visited it twice, I have always felt that it was too dangerous to allow the daily tour groups that visit the uninhabited island volcano by boat and helicopter."

The prime minister arrived Monday night in Whakatane, the town closest to the eruption, where day boats visiting the island are docked. Whakatane has a large Maori population.

Ardern met with local council leaders on Monday. She is scheduled to meet with search and rescue teams and will speak to the media at 7 a.m. local time (1 p.m. EST), after drones survey the island, as CNN reported.

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