An area just below the Arctic Ocean rose to 84 degrees Fahrenheit in recent days, a staggering 30 degrees higher than the average temperature for this time of the year, according to the Washington Post.

Although the jump is likely due to an isolated weather event, the frequency of regional heat waves has risen in recent decades, which indicates the long-term effects of climate change.

“Usually when you have a somewhat isolated hot spot, it’s going to be related to an atmospheric weather pattern,” Mark Serreze, director of the National Snow and Ice Data Center (NSIDC), told Global Citizen. “You have a storm coming in and it’s drawing a lot of warm air into the region.

“But what we’ve been seeing is more of these sorts of heatwaves up there, especially extreme winter heat waves over the Arctic Ocean,” he added. “The point is the Arctic is just getting warmer and warmer and it’s not something theoretical, this is just what the data is showing.”

In many ways, the Arctic is the world’s warning system when it comes to climate change, said Serreze. The polar regions are especially prone to global warming because of powerful feedback loops that occur. As Arctic sea ice melts from higher temperatures, it exposes darker water that absorbs more heat from the sun, causing more warming.

Because of this dynamic, temperatures in the Arctic are warming twice as fast as the global average.

“Extreme heat or cold are more related to weather phenomena rather than long term anthropogenic forces,” said Julienne Stroeve, senior researcher at the NSIDC. “This heat wave is definitely an extreme event, but it’s the long-term warming trend that we’re really worried about.”

Read More: Scientists Warn That the Arctic Might Not Be the Arctic for Very Long

The Arctic has already lost 95% of the its oldest ice and daily ice levels were at their lowest levels in recorded history throughout April. Between 1970 and 2015, Arctic ice has nearly halved.

Over the course of April, overall water temperatures in the Arctic ranged from 5 degrees to 14 degrees Fahrenheit above normal, with a few notable exceptions.

As the polar region warms, ice melt is accelerating, endangering entire ecosystems and disrupting climatic systems in ways that threaten the entire planet.

“I feel like we’re doing this huge experiment to our climate system and we don’t fully know the consequences,” Stroeve said. “We run climate models to determine how quickly it’s going to change, but we don’t have another planet to experiment on.”