Pack ice coverage in the Arctic Ocean has fallen to the second-lowest level since satellite observations began in 1979, US government scientists said Monday.
Until this month, only once in the past 42 years has Earth’s frozen skull covered less than 4 million square kilometers (1.5 million square miles).
The Arctic could experience its first ice-free summer as early as 2035, researchers reported last month in the journal Nature Climate Change.
But all that melting snow and ice doesn’t directly raise sea levels, just like melting ice cubes don’t spill a glass of water, which begs the awkward question: Who cares?
Admittedly, this is bad news for polar bears, which, according to a recent study, are already on their way to extinction.
Yes, this certainly means a profound transformation of the region’s marine ecosystems, from phytoplankton to whales.
As it turns out, there are several reasons to be concerned about the side effects of shrinking Arctic sea ice.
Perhaps the most fundamental idea, scientists say, is that shrinking ice sheets are not only a symptom of global warming, but a driving force behind it.
“The removal of sea ice exposes the dark ocean, which creates a powerful feedback mechanism,” geophysicist Marco Tedesco of Columbia University’s Earth Institute told AFP.
But when the mirror surface was replaced with dark blue water, about the same percentage of the Earth’s thermal energy was absorbed.
We’re not talking about stamp area here: the difference between the average ice sheet minimum from 1979 to 1990 and the lowest point recorded today is over 3 million square kilometers – twice that of France, Germany and Spain combined.
The oceans are already absorbing 90 percent of the excess heat produced by anthropogenic greenhouse gases, but this comes at a cost, including chemical changes, massive marine heatwaves and dying coral reefs.
Earth’s complex climate system includes interconnected ocean currents driven by winds, tides, and the so-called thermohaline circulation, itself driven by changes in temperature (“warmth”) and salt concentration (“brine”).
Even small changes in the ocean conveyor belt (which travels between the poles and spans all three oceans) can have devastating effects on the climate.
For example, nearly 13,000 years ago, as the Earth transitioned from an ice age to an interglacial period that allowed our species to thrive, global temperatures suddenly dropped a few degrees Celsius.
Geological evidence suggests that a slowdown in thermohaline circulation caused by a massive and rapid influx of cold freshwater from the Arctic is partly to blame.
“Fresh water from melting sea and ground ice in Greenland disrupts and weakens the Gulf Stream,” part of a conveyor belt that flows in the Atlantic Ocean, said researcher Xavier Fettweiss of the University of Liege in Belgium.
“That’s why Western Europe has a milder climate than North America at the same latitude.”
The huge ice sheet on land in Greenland lost more than 500 billion tons of clean water last year, all of which leaked into the sea.
The record amount is partly due to rising temperatures, which are rising at twice the rate in the Arctic than the rest of the planet.
“Several studies have shown that the increase in summer Arctic highs is partly due to the minimum extent of sea ice,” Fettwiss told AFP.
According to a study published in the journal Nature in July, the current trajectory of climate change and the onset of an ice-free summer, as defined by the UN Intergovernmental Panel on Climate Change Climate Panel, is less than 1 million square kilometers. by the end of the century, the bears will indeed starve to death.
“Human-induced global warming means polar bears have less and less sea ice in the summer,” study lead author Stephen Armstrup, chief scientist at Polar Bears International, told AFP.