If your life has felt like a hot mess this year, you're not alone. Same goes for the Arctic, which month after month has seen its ice cover contract to new lows. By late September, Arctic sea ice may reach its lowest extent since satellite record-keeping began. Chunks of sea ice, open ponds and meltwater seen over the Chukchi Sea on Saturday, 16 July 2016. Image: NASA
And that's got scientists in a tizzy, because if there's one thing geologic history has taught us, it's that sudden drops in Arctic ice cover are often the tip of the proverbial iceberg for a whole slew of planetary feedbacks.
It's difficult to keep up with all the climate-related records our world has been smashing, so here's a quick recap of what's been happening up north. At the close of 2015 (currently the hottest year in recorded history, but not for long), the Arctic was already sweating iceberg-shaped bullets, thanks to freakishly warm weather brought on by a combination of a monster El Niño and the underlying global warming trend. Then 2016 burst on the scene, with temperatures at the North Pole rising some 27C above normal. The Arctic stayed exceptionally hot through January and February.
Degree days below freezing in the Arctic, which are at their lowest extent since 1980. We're going to need a bigger y-axis if this keeps up. Image: Andrew Slater
By the time March rolled around, the atmosphere was loaded with heat, and Arctic sea ice was already starting to look thin. NASA confirmed that it was indeed the smallest wintertime Arctic sea ice extent on the record books, peaking at some 14.5 million square km.
Then, the Arctic started to melt. And it kept going, and going, and going, smashing record after record, month after month.
As of this writing, we've just come off the fifth record-low sea ice month this year. Every month except March has marked an all-time monthly low, with June sea ice maxing out a full 260,000 square km below the previous record low, set in 2010. June sea ice was also 1.36 million square km below the 1981-2010 average. Put another way, a Texas-sized chunk of sea ice has disappeared from our planet's north pole between the early 1980s and today.
Image: National Snow and Ice Data Center
"The first six months [of 2016] have certainly primed this year to be a record," NASA sea ice scientist Walt Myer told Gizmodo in a press call, adding that we'll need to see the data from July and August before we can give this summer the gold. (While a period of sustained high pressure over the Arctic helped fan the flames early, recent weeks have brought a cooler, low pressure system to the region.)
"Regardless, it's going to be a very low ice year," Myer continued. "Which is fitting with what we've seen over the last 15 years and beyond." If recent trends are any indicator, we're speeding toward a future free of summertime sea ice by mid-century, and all of the complex feedbacks that go along with it.
The first of those is albedo, or the reflectivity of the planet's surface. As shiny, ice-covered surface gives way to darker ocean water, the Arctic absorbs additional heat. "That's changing the Arctic climate," Myer said. "You have a lot more heat going into the system [in the summer], meaning more warm temperatures in the fall."
A large pool of meltwater over sea ice, as seen on a NASA aerial survey on July 14th, 2016. Image: NASA/Operation IceBridge
Indeed, NASA researchers are finding that the frequency of aquamarine ponds called "melt pools" on the surface of sea ice sheets are a very good predictor of the summertime sea ice minimum, for exactly this reason. "Melt ponds are a major contributor to radiation and heat in the Arctic," said Nathan Kurtz, a sea ice researcher at NASA's Goddard Spaceflight Center. "The more of them there are, the more energy is being absorbed from the sun, and transferring into the ice and the ocean."
This melt-driven feedback loop is likely contributing to the rapid warming we're seeing in the Arctic — approximately three times the globally-averaged rate.
Rapid warming up north, in turn, is contributing to profound shifts on land, including a greening of the Arctic tundra, the collapse of permafrost banks along Alaska's northern shores and elsewhere, and an intensification of fire season. "Both fire [increases] and greening are happening on a continental scale," said Charles Miller, an Arctic ecologist at the Jet Propulsion Laboratory.
Satellite data since the 1980s indicate a widespread greening across Canada and Alaska, which is related to the rapid warming trend in this part of the world. Green colours indicate an increase while brown colours indicate a decrease. Image: NASA/GSFC/Scientific Visualisation Studio/Cindy Starr
There could also be more global effects. Some evidence indicates that Arctic warming — which is causing a change in the temperature gradient between the equator and the poles — could be shifting the polar jet stream, causing it to meander more north and south rather than travelling a straight line. A recent study from Rutgers University linked a wavier jet stream to an uptick in extreme weather events, noting that "these are the types of phenomena that are expected to occur more often as the world continues to warm and the Arctic continues to lose its ice."
However, as the National Snow and Ice Data Center's Julienne Stroeve told Gizmodo, these links are still controversial. "Everybody agrees that we should see an effect, but whether or not the signal has emerged above the chaotic climate system is not clear," she told Gizmodo.
Climate feedbacks aside, the rapid disintegration of Arctic sea ice will have a dramatic impact on the ecology of this unique part of our planet. The ice shelf is home to numerous charismatic megafauna, including Pacific walruses and polar bears, which are having to swim further and expend more energy to find a meal. Meanwhile, at the other end of the food chain, biologists are starting to worry about subtle changes in ice algae blooms affecting the reproduction of tiny, algae-eating crustaceans called copepods. This in turn could reduce the food supply for everything from seabirds to whales.
It's a domino effect for the plants, animals and ecosystems of the Arctic, and for the planet at large. And let's not forget who else that planet supports: All of us.