• The Arctic is rapidly changing from the climate crisis, with no "new normal," scientists warn.
• Wildfires and permafrost thaw are making the tundra emit more carbon than it absorbs.
• From beaver invasions to giant holes, drastic changes in the Arctic are affecting the entire planet.

From Alaska to Siberia, the Arctic is changing so rapidly that there is no "normal" there now, scientists warn. The consequences reach across the globe.

The Arctic tundra now releases more carbon than it naturally draws down from the sky, as wildfires burn down its trees and permafrost thaw releases potent gases from its soil.

Once-brown regions are turning green with vegetation, while green areas are turning brown and barren. Sea ice and herds of caribou are disappearing.

This summer was the wettest on record for the Arctic overall, as rain is becoming more common than snow in some areas. Region by region, though, rainfall and the snow season are knocking down both high and low records.

Decades of data on "vital signs" suggest that "the Arctic exists now within a new regime, in which conditions year after year are substantially different than just a couple of decades ago," Twila Moon, a scientist at the National Snow and Ice Data Center, said in a briefing on Tuesday.

"Climate change is not bringing about a new normal," she added. "Instead, climate change is bringing ongoing and rapid change."

That's because the Arctic is warming about four times faster than the rest of the planet, according to previous research.

The increase in average temperatures is changing weather and landscapes in the Arctic, speeding up the climate crisis worldwide.

Giant holes, beaver invasions, and polar wildfires

For example, beavers are moving into Alaska's tundra and transforming its waterways with their dams, as warmer conditions have brought more wooded, comfortable riverbanks for them.

In Siberia, a giant hole in the ground is rapidly growing because the permafrost — a layer of soil that used to be permanently frozen — is thawing.

That's an extreme example, but melt and thaw is happening all over the planet's northernmost regions. Combined with drastic swings in weather year-to-year, these changes are wreaking havoc on Arctic landscapes, ecosystems, and people.

"These dramatic differences are making it difficult for communities to plan and they create safety issues for people who are used to more stable ice, snow, and temperature," Moon said.

She was presenting the Arctic Report Card, an update that the National Oceanic and Atmospheric Administration publishes each year, at the fall meeting of the American Geophysical Union.

This year's report revealed a crucial shift in northern landscapes: The Arctic tundra is no longer a net carbon sink, with its boreal forests pulling carbon dioxide from the sky. Now it's a net source of carbon emissions.

"This transition from a carbon sink to a source is of global concern," Brendan Rogers, a scientist studying the tundra at the Woodwell Climate Research Center, said in the briefing.

He added that the tundra's carbon emissions are relatively small for now, "but it's that transition that we're concerned about."

This shift is partly due to giant polar wildfires burning down tundra vegetation and all the carbon it's stored. It's also because of permafrost thaw, which releases large amounts of methane — a heat-trapping gas more potent than carbon dioxide — as bacteria in the soil digest thawing plant matter.

Meanwhile, rising Arctic temperatures are driving ice melt, including on the Greenland Ice Sheet, which is a major contributor to sea-level rise worldwide. Rising oceans are already increasing flooding in coastal cities across the planet.

For example, US coastal cities from Boston to San Diego have seen more and more flood days per year every decade since 1950, according to the Environmental Protection Agency.

Arctic science is more important than ever

Reporters asked the NOAA scientists about the incoming Trump administration and whether they were concerned about losing funding for their Arctic research.

"The need, the requirement, the demand signal if you will, is higher than ever before," Richard Spinrad, the NOAA Administrator, said in the briefing.

Changes in extreme weather and sea level across the globe show that "there's a need for these investments to increase right now," he said, adding that studies have shown "the return on those investments is extraordinary, in many cases 10 to 1 in terms of protection of lives and property."

"I can't imagine that Tesla just didn't think about this when they put this giant shelf in front of the lights."

• A snowstorm blanketed South Korea's capital on Wednesday and Thursday, photos show.
• The snowstorm was the heaviest in the month of November since records began in 1907.
• The severe weather resulted in at least five deaths and led to transportation chaos.

Heavy snow continued to blanket South Korea's capital for a second day running on Thursday, following a record-breaking snowstorm in Seoul the previous day.

Photos of the snowfall show South Koreans enjoying the unusual winter wonderland, the first snow of the season.

However, the severe weather also resulted in a number of deaths and led to travel chaos.

According to Reuters, at least five people died as a result of the adverse weather, with four fatalities due to structures collapsing under the weight of the snow, and one person dying in a traffic accident due to icy roads.

On Wednesday, 11 people were injured after 53 cars were involved in a pile-up in the city of Wonju, about 70 miles east of Seoul, amid the snowy conditions, the Yonhap News Agency reported.

The news agency said the snow caused trees and branches to buckle and collapse across Seoul and the surrounding regions, which led to authorities blocking entry to some roads, power lines snapping, and delays on some subway lines.

Yonhap also reported that more than 140 flights, the majority of them international, were canceled due to the weather.

Wednesday's snowfall in Seoul brought about 6.5 inches of snow to the city and surrounding areas, making it the heaviest snowfall in November since records began in 1907, per the Yonhap News Agency.

The previous record, set in 1966, saw considerably less snowfall, at about 3.7 inches, per CNN.

Data from the Korea Meteorological Administration (KMA) showed 11.3 inches of snow in Seoul at 8 a.m. local time on Thursday, close to the overall record of 12.2 inches recorded at a Seoul weather station in March 1922.

According to the KMA, Suwon, a city about 25 miles from Seoul, received almost 17 inches of snow on Thursday morning.

The snow is expected to lessen over Thursday.