Rapid ice loss is already having a devastating impact in the world’s Arctic and Antarctic regions. And in an explainer on the implications of an ice-free Arctic, CBC stresses that what happens in the polar region doesn’t stay there.
“Snow and ice have long played a vital role in moderating Earth’s climate. The white surfaces reflect the sun’s radiation, which in turn helps maintain a comfortable temperature for life on the planet,” CBC states.
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“But with a warming planet, that ice melts or thins, exposing the dark water below, which absorbs that radiation. So each year the global temperature rises, melting more ice and snow. It’s a positive feedback loop: warming causes ice melt, ice melt causes warming. And that process—also called Arctic amplification—leads to what we are observing now, which is a rapidly changing climate.”
Last month’s IPCC report on the world’s oceans and cryosphere (its ice-covered regions) projected that the Earth could see an ice-free Arctic every 100 years if humanity holds average global warming to 1.5°C, or every three years if warming hits 2.0°C. That prompted CBC to explain the working definition of “ice-free Arctic”—it means less than a million square kilometres remaining in mid-September, when the region’s ice cover hits its annual minimum, compared to an average minimum of about 6.3 million square kilometres between 1981 and 2010.
“Usually when we talk about ice-free, it’s virtually ice-free,” said Woods Hole Research Center Senior scientist Jennifer Francis. “It’s really during the late summer at the time when we usually see the minimum occur, which is right about now.”
At 4.16 million square kilometres, 2019 was considered a bad year for Arctic ice, and the 13 lowest sea ice extents ever recorded have all occurred in the last 13 years, CBC says. “It’s been estimated that we’ve lost about three-quarters of the sea ice in terms of volume. Which is crazy. It’s happened within 40 years,” said Francis. “It is just a mind-boggling statistic to throw at people. It still takes my breath away.”
The fundamental difference between the Arctic and the Antarctic—an ocean surrounded by continents, versus a continent surrounded by oceans—defines their roles and importance as triggers for ice loss and sea level rise, CBC explains. In the Antarctic, rapid ice melting on land is leading to a rise in sea levels. In the Arctic, the reflectivity of ice—especially multi-year ice—plays a crucial role in regulating the planet’s temperature.
“While some people believe that an ice-free Arctic could be a good thing—opening up a new shipping route, oil and gas extraction, and tourism—there are likely deep repercussions,” CBC notes, including greenhouse gas emissions resulting from fossil production, challenges to Canada’s Arctic sovereignty, and the risk of environmental disasters due to increased industrial activity. But the risks of a warming Arctic also extend beyond the region.
“It’s an experiment on a grand scale,” said World Wildlife Fund Arctic Vice President Paul Crowley. “The north, the Canadian Arctic, folks in the north, our communities are already challenged. So this is just another layer.”
Crowley said Arctic permafrost melt is already threatening northern homes, roads, and other infrastructure, and the people and communities that depend on them. “And then there’s the weather around the world,” CBC adds.
“The jet stream, a column of air that travels from west to east that drives weather across the northern hemisphere, relies on the temperature difference between the Arctic and the south. But when the temperature difference is not as pronounced, the jet stream begins to develop kinks. This can have widespread effects, such as creating systems that prolong heat waves in southern Ontario and Quebec or even Europe, or slow hurricanes to a near standstill, as was seen with Dorian earlier this month.”