Eastern Arctic not getting warmer, scientists say
A team of glacial ice experts say Mother Nature’s thermostat has kept the eastern Arctic at about the same temperature since 1960
Scientists probing the depths of glacial ice on Baffin Island have found no evidence of global warming in the eastern Arctic.
In fact, researchers with the Canadian Geological Survey say the most significant warming trend here ended about 10,000 years ago at the end of the last ice age.
“This part of the world, over the last 30 or 40 years, hasn’t changed very much,” said Dr. Roy Koerner, a glaciologist who has just completed a three-year study of the Penny Ice Cap.
“If you look at it, not on a year-to-year basis, but over the whole period, there’s no real warming or cooling trend.”
Koerner’s findings will form part of a scientific article that he and colleagues from the Geological Survey plan to submit this summer to the scientific journal Nature.
In 1995 and 1996, scientists removed ice core samples from the Penny Ice Cap, drilling hundreds of metres from surface to bedrock in the Auyuittuq Mountains.
“If you take an ice core, it’s like going through a tree with tree rings. The snow at the top collects every year, but doesn’t melt completely.
“You virtually have a record of the snow conditions and temperatures that covers the whole life of the ice cap, in this case 100,000 years.”
The samples were analysed for climatic change by looking at ice layers.
“If it’s a warm summer, you form lots of ice layers in the snow. If it’s a cold summer, there’s not many ice layers. So it gives us a kind of summer record.”
Samples of melted snow and ice were further analysed for the presence of two slightly different types, or isotopes of oxygen atoms.
The relationship between these isotopes tells scientists at what temperature the snow formed each year, and allows them to chart a record of annual temperatures.
Though man-made pollutants in the earth’s atmosphere are widely believed to contribute to climatic changes, Koerner said scientists need a better understanding of how the planet’s climate changes naturally.
“One has to be understand this in order to put what we call global warming into perspective,” he said.
In other words, the connection between man-made pollution and warmer temperatures may be more complicated than previously thought.
“It could be just another natural fluctuation,” said Koerner.
Drilling on the Penny Ice Cap followed similar work on Devon Island and on northern Ellesemere Island.
Taken together, the findings show temperatures in the eastern Arctic were actually at their warmest as the planet moved out of the last ice age.
“There’s a change in temperature of approximately 10 to 15 degrees celsius,” said Koerner. “It was extremely warm.”
Over the next 10,000 years, the theory goes, the world cooled off by one or two degrees celsius.
“This cooling reached an absolute bottom 150 years ago,” Koerner said. “Then the climate started to warm and it warmed until about 1960. Then it cooled off a bit, and it hasn’t changed much since.”