|Posted on April 25, 2021 at 4:20 PM|
From the New York Times
The North Pole is melting.
The thick ice that has for ages covered the Arctic Ocean at the pole has turned to water, recent visitors there reported yesterday. At least for the time being, an ice-free patch of ocean about a mile wide has opened at the very top of the world, something that has presumably never before been seen by humans and is more evidence that global warming may be real and already affecting climate.
The last time scientists can be certain the pole was awash in water was more than 50 million years ago. ''It was totally unexpected,'' said Dr. James J. McCarthy, an oceanographer, director of the Museum of Comparative Zoology at Harvard University and the co-leader of a group working for the Intergovernmental Panel on Climate Change, which is sponsored by the United Nations. The panel is studying the potential environmental and economic consequences of marked climate change.
Dr. McCarthy was a lecturer on a tourist cruise in the Arctic aboard a Russian icebreaker earlier this month. On a similar cruise six years ago, he recalled, the icebreaker plowed through an icecap six to nine feet thick at the North Pole.
This time, ice was generally so thin that sunlight could penetrate and support concentrations of plankton growing under the ice. Dr. McCarthy said the icebreaker's Russian captain, who has made the voyage 10 times in recent years, said he had never before encountered open water at the pole. Another lecturer, Dr. Malcolm C. McKenna, a paleontologist at the American Museum of Natural History, said the ship, the Yamal, crunched through miles of unusually thin ice and intermittent open water on the approach from Spitsbergen, Norway, to the pole. When the ship reached the pole -- which Dr. McKenna and his wife, Priscilla, confirmed with a handheld Global Positioning System navigation device -- water lapped its bow.
''I don't know if anybody in history ever got to 90 degrees north to be greeted by water, not ice,'' Dr. McKenna said in an interview. He instantly snapped pictures to document the phenomenon in photographs.
The Yamal eventually had to steam six miles away to find ice thick enough for the 100 passengers to get out and be able to say they had stood on the North Pole, or close to it. They saw ivory gulls flying overhead, the first time ornithologists said they had ever been sighted at the pole.
Over the last century, the average surface temperature of the globe has risen by about 1 degree Fahrenheit, and the rate of warming has accelerated in the last quarter-century. That is a significant amount, considering that the world is only 5 to 9 degrees warmer now than it was in the last ice age, 18,000 to 20,000 years ago.
Scientists and policy makers are still arguing about whether this is a natural fluctuation or an effect of industrial society's releasing heat-trapping gasses into the atmosphere.
''Some folks who pooh-pooh global warming might wake up if shown that even the pole is beginning to melt at least sometimes, as in the Eocene,'' Dr. McKenna said.
The Eocene was the geological period when the world's climate grew significantly warmer. Around 55 million years ago, according to sedimentary and fossil evidence, tropical vegetation spread inside the Arctic and Antarctic circles. Water and jungles dominated the polar environments, and in the generally warm world, mammals for the first time grew in number, size and diversity. Previous studies of satellite and submarine observations have seemed to establish a warming trend in the northern polar region and raise the possibility of a melting icecap.
Scientists at the Goddard Space Science Institute, a NASA research center in Manhattan, compared data from submarines in the 1950's and 1960's with 1990's observations, demonstrating that the ice cover over the entire Arctic basin has thinned by 45 percent. Satellite images have revealed that the extent of ice coverage has significantly shrunk in recent years.
Dr. McCarthy said he would report the encounter with open polar water to environmental scientists and consult other scientists to see if new satellite remote-sensing data have detected the extent of the melting.
Recalling the reaction of passengers when they saw an iceless North Pole, he said: ''There was a sense of alarm. Global warming was real, and we were seeing its effects for the first time that far north.''
In their models of climate patterns, scientists have long suggested that the northern polar region would be affected earlier and more seriously than the southern region.
They said that the greater expanse of land in the northern hemisphere should respond more rapidly to temperature change, presumably leading to marked climate change