The sun sets as rain falls beyond floating ice and icebergs in Disko Bay above the Arctic Circle in Ilulissat, Greenland, on Sept. 4, 2021. (Mario Tama/Getty Images)

Here’s why that matters.

The planet’s warming is transforming the sprawling and fragile Arctic, moving it toward a future that can be summed up in four words: more rain, less snow. But now researchers say that unprecedented shift — and the profound impacts that are likely to accompany it — could come decades sooner than previously thought.

Parts of the Arctic could become dominated by rain rather than snow during certain seasons by 2060 or 2070, according to new findings published in the journal Nature, particularly if the Earth continues to warm at its current rate. When those changes arrive, they will probably trigger consequences that affect not only local people and wildlife, but communities around the world.

Ice vanishing more rapidly could quicken sea-level rise along coastlines. Melting permafrost could release massive amounts of planet-heating gases such as methane and carbon dioxide. The “greening” of once-frozen landscapes could provide fuel for ravenous wildfires that spew more greenhouse gases into the air and further warm the atmosphere.

“What happens in the Arctic doesn’t stay in the Arctic,” Michelle McCrystall, a lead author of Tuesday’s study and a postdoctoral researcher at the University of Manitoba, said in an interview.

U.N. climate report: Monumental change already here for world’s oceans and frozen regions

McCrystall and her colleagues used the most up-to-date climate models to detail how the Earth’s northernmost polar region, which has been warming much faster than the rest of the planet, will probably undergo more rapid and intense hydrological cycles in the future. This shift could be most pronounced during autumn, they found.

Warmer air temperatures, melting sea ice and the atmosphere’s increasing ability to carry moisture all point toward increased rainfall in many parts of the Arctic. In some cases, scientists are already observing the beginning of those trends, and they expect them to accelerate depending on the globe’s temperature rise.

The Arctic is not monolithic, McCrystall said. Some areas, including in Greenland, could actually see increased snowfall in coming decades, helping to stabilize fragile ice sheets but not completely offsetting mass losses. And the models that scientists use to estimate precipitation through 2100 are inherently uncertain, given the lack of data from direct observations of rainfall, snow, wind and temperatures across the vast region. “There’s no crystal ball,” she added.

Previous research shows that while snowfall may increase in the near future, precipitation will turn into rain as warming continues.

Marilena Oltmanns, a climate researcher with the United Kingdom’s National Oceanography Centre, said in an email that while scientific models tend to improve over time, projections about future shifts in snow and rain remain tricky.

“Precipitation is one of the most difficult variables for models to get right,” said Oltmanns, who was not involved in the study.

Still, Tuesday’s study suggests that rain will probably be a much more prominent feature for large swaths of the Arctic in the future as snow and ice retreat.

That shift toward a rain-dominated reality, researchers wrote, could come “approximately one or two decades earlier” than expected. Such a change could have “implications for the stability of social-ecological systems in the Arctic and the rate at which systems changes occur,” they added.

The study reflects scientists’ ongoing effort to understand the significant changes already unfolding across the Arctic, which is warming nearly three times as fast as the rest of the world.

Rain falls on icebergs in Disko Bay, Ilulissat, Greenland, on Sept. 4, 2021. (Mario Tama/Getty Images)

The Arctic of inhospitable, barely accessible and icebound expanses is transforming. December’s Arctic Report Card, an effort led by the National Oceanic and Atmospheric Administration and involving 133 scientists from 15 countries, detailed how climate change has reshaped the Arctic into a place that can hit triple-digit temperatures, endure raging wildfires and suffer greater ice loss with each passing year.

In late July, polar researcher Zoe Courville gathered with several colleagues to discuss the future of research stations as Greenland’s climate deteriorates. This year its ice sheet lost more ice than it gained for the 25th year in a row.

Greenland ice sheet experiences record loss to calving of glaciers and ocean melt over the past year

Several engineers considered how to plan for increased temperatures, melt events and storm events over just the next several decades. Then, Courville recalled, one of the engineers asked what if it rains at the summit.

“I remember just laughing, you know, like, ‘Oh, let’s not think about rain right now,’ ” said Courville, a research engineer at the Cold Regions Research and Engineering Laboratory. “We don’t want to even have to cross that bridge yet. … Introducing liquid water into this system really does wreak havoc.”

Two weeks later, it rained on the summit of Greenland for the first time on record.

The Arctic could get more rain and less snow sooner than projected.

Here’s why that matters.