A view of the giant hole in Siberia, Russia. (Marya Zulinova, press service of the Governor YaNAO)

In 2014, massive holes began appearing in parts of Siberia. One giant crater in the Yamal Peninsula spanned more than 100 feet wide, gaining international attention and prompting theories about how it could have formed. In the following year,dozens more of these mystery holes were spotted nearby. Since then, scientists have been able to determine that the mystery hole wasn't an impact from a meteorite. The most likely explanations so far? These holes could have been formed by underground methane explosions or by the freezing and melting of the landscape, creating geological formations known as "pingos."

One thing is for certain: warmer temperatures in the Arctic have played a part.

If the holes were caused by methane explosions, it could be the same phenomenon that's been offered as an explanation behind the Bermuda Triangle, meaning that researchers could be dealing with methane explosions that, when underwater, are powerful enough to sink entire ships.

(MORE: Is This the Scientific Reason Behind the Bermuda Triangle?)

Once scientists were able to rappel to the bottom of the crater, they found something that supported one of the two theories: high levels of methane, 9.6 percent compared to the normal 0.000179 percent.

"Given low enough temperatures and high enough pressure, methane and water can freeze together into what's called a 'methane hydrate,'" Tech Insider reports. "Permafrost keeps everything bottled up but when it thaws, so does hydrate. Methane is released as a gas,building up pressure - until the ground explodes."

If methane really is behind these giant holes, that means that permafrost is what's preventing these explosions from becoming more and more common. That threat is becoming all the more concerning as Arctic temperatures continue to increase, causing the permafrost to thaw.

This past winter, the maximum measurement of Arctic sea ice was lower than it's ever been for the second year in a row. Last year, the average air temperature in the region was 2.3 degrees above average, the highest temperature ever recorded.

The craters in Siberia may be an indicator of what New Scientist notes is commonly referred to as a "methane time bomb."These explosions aren't concerning just because of their mere size. They're concerning because methane is a major contributor to the warming of the atmosphere. As scientists continue to dig deeper into what's going on behind these mysterious craters, we'll have more clues about the future of the Arctic –and the future of our planet.

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This June 2010 photo shows a sinkhole covering a street intersection in downtown Guatemala City, Guatemala. (AP Photo/Moises Castillo)