Global warming limits laid out by the landmark Paris climate agreement do not rule out an Arctic devoid of summer sea ice, according to new research out this week.

The findings, published July 9, are a grim indicator that even a best-case scenario for limiting climate impacts could still have unprecedented implications for the planet.

They also underscore the potential for even more dire situations, which are growing more likely as countries, including the United States, fail to reach their individual climate goals under the Paris Agreement. The pact, backed by virtually every country around the world, aims to keep temperatures from increasing past 2 degrees Celsius (3.6 degrees Fahrenheit) over preindustrial temperatures, with the aspiration of limiting that increase to 1.5 degrees Celsius (2.7 degrees Fahrenheit).

Published by scientists from South Korea, Australia, and the United States, the new research appears in this week’s issue of Nature Communications and offers an ominous forecast for climate advocates. Using 31 different climate models, the experts found that there is at least a 6% probability that summer sea ice in the Arctic Ocean will disappear in a scenario long cited as the most optimistic: limiting global warming to 1.5 degrees Celsius.


That increase is the one recommended as an advised threshold by the Paris Agreement. According to the new findings, the higher temperature increase of 2 degrees Celsius Arctic summer sea ice could have a 28% chance of disappearing.

Probabilities of Arctic summer sea ice disappearing when crossing certain global warming levels. CREDIT: Elke Zeller and Roman Olson

Notably, that still leaves a decent chance of ensuring ice remains in the Arctic. However, experts increasingly worry that limiting warming below 2 degrees Celsius is unlikely. And recent reports have underscored that dramatic and urgent action is required to avert catastrophic climate impacts.

Moreover, this week’s study highlights the need to establish what level of warming would bring forth an ice-free Arctic — a scenario in which there would be no white mass of ice to reflect sunlight and maintain cooler ocean temperatures. The less sea ice there is to reflect the heat, the more warming is likely to occur. While the researchers note that Arctic sea ice is all but guaranteed to disappear in a situation involving more than 2 degrees Celsius of warming, the potential for such a melting at lower temperatures also remains cause for alarm.

“Decision making in a warming world requires an understanding of the probabilities of certain climatic events to occur,” a press release for the study emphasized.

Preparing for various scenarios and the extent of possible impacts associated with climate change lies at the heart of the study. Jason Evans, a professor at the Climate Change Research Center in UNSW Australia in Sydney, drove home that point in a statement accompanying the research.


“Our work provides a new statistical and mathematical framework to calculate climate change and impact probabilities,” said Evans.

According to the researchers, their work marks the first established mathematical framework allowing for such warming scenarios to be tested and their subsequent impacts assessed.

But the research also points to an ominous possibility. Meeting even the higher threshold of warming laid out in the Paris Agreement has never been guaranteed. With the lower threshold now associated with a potentially ice-free Arctic during the summer, pressure is likely to mount for signatories of the agreement to act — especially in the United States, where President Donald Trump has pledged to exit the pact.

Few countries are currently meeting their Paris targets, including the United States, to the chagrin of the United Nations. The global body’s head, Secretary General Antonio Guterres, warned at the end of last month that all countries will need to stop building new coal plants by next year and cut greenhouse gas emissions by at least 45% by 2030.

“It is plain to me that we have no time to lose,” Guterres said, delivering comments at a summit in Abu Dhabi in the United Arab Emirates. “Sadly, it is not yet plain to all the decision makers that run our world.”


The U.S. government is eyeing a radically different path. Trump has repeatedly sought to rescue the floundering coal industry, going so far as to float bailing out both coal and nuclear power. The president has also expressed strong support for oil and gas efforts nationally, despite their established contribution to global warming.

Secretary of State Mike Pompeo moreover recently highlighted the economic opportunities of a melting Arctic. “Steady reductions in sea ice are opening new passageways and new opportunities for trade,” the official said in May.

But the administration’s stance appears to be becoming an electoral liability for the White House as climate issues gain prominence nationally. It has also given Democratic presidential contenders an opening.

On Tuesday, Sen. Bernie Sanders (I-VT), a Democratic frontrunner, unveiled legislation declaring a “climate emergency,” part of a partnership with Reps. Alexandria Ocasio-Cortez (D-NY) and Earl Blumenauer (D-OR). And on Wednesday, Sen. Elizabeth Warren (D-MA) reintroduced a bill that would force public companies to disclose their greenhouse gas emissions as well as climate risks associated with their businesses. The bill coincides with a report finding that only one in eight of the world’s most-polluting companies are on track to meet climate goals in line with the Paris Agreement.