Photo Credit: Yamal Regional Government Press Service

In July 2014, a helicopter pilot flying over Northern Russia's remote Yamal Peninsula came across a massive crater in the thick, permanently frozen subsurface layer of soil known as permafrost. As news of the gaping hole that measured an impressive 100-meters in diameter spread, people all over the world began wondering about its origin.

Some speculated that the crater was created by meteorites while others thought it was caused by a missile. Then there those that thought it was the work of aliens! But as several more craters were discovered in the vicinity, experts began to seek out a logical scientific explanation.

Four Arctic craters all found this year (Photo Credit: Vasily Bogoyavlensky Deputy director of the Moscow-based Oil and Gas Research Institute)

Carolyn Ruppel, the Chief of U.S. Geological Survey’s Gas Hydrates Project, theorized the craters were the result of collapsing pingos - mounds of earth-covered ice that are prevalent in the Arctic and subarctic regions. She thought that the increasingly warmer temperatures due to global warming melted the frozen hills that can reach heights of up 70-meters and caused the ground underneath to give away.

While this was a plausible explanation for the shallower craters, it was not enough to explain the large ones. Experts thought they were too deep to have been created just by melting pingos. A closer examination of the rocks at the edge of the craters indicated the possibility of some sort of explosion.

Photo Credit: Vasily Bogoyavlensky Deputy director of the Moscow-based Oil and Gas Research Institute

This led scientists to speculate that the melting of the permafrost resulted in releasing massive amounts of trapped methane, which exploded leaving behind giant holes in the ground. This theory was validated by locals who reported seeing light flashes in the area. Additionally, when experts examined the air inside the first crater (now dubbed B1), they found methane levels of almost 10%, substantially higher than the typical .000179%.

To put the matter to rest, this July a team of researchers led by Professor Vasily Bogoyavlensky, the Deputy Director of the Moscow-based Oil and Gas Research Institute, went to examine the craters up close. It turns out that both theories are valid. According to the Russian experts, the warmer temperatures cause the pingos to melt. As they are melting, the cracks in the ground help the methane to escape. When enough gas accumulates, it explodes and creates massive craters.

Image Credit: NOAA.Gov

Though the mystery of the craters may have been solved, the explanation is resulting in even more anxiety among scientists. With global temperatures on the rise, the amount of methane escaping from the ground can only increase. This is dangerous even if the gas does not explode.

That's because like carbon dioxide, methane also traps heat. The only difference is that methane is twenty times more efficient at doing so. Hence, large amounts of the gas in the atmosphere will only increase the temperatures further, which of course would mean more permafrost melting and more methane being released! This vicious cycle could further exacerbate the effects of climate change, making the region which is a major source of oil and gas reserves, highly volatile.

Photo Credit: Vladimir Pushkarev/Russian Centre of Arctic Exploration via Siberian Times

As to how so much methane got trapped under the icy grounds? According to experts, there are two sources responsible. The first is methane clathrate - Molecules of methane that are frozen into ice crystals and buried deep underground or underwater. The second source of gas is the organic matter - Dead plants and animals that have been buried in the frozen permafrost for thousands of years. While both are harmless when under ice, they can wreak havoc to the area's weather patterns and ground stability as is the case here, if allowed to emerge.

Northern Russia is not the only Arctic region being affected by climate change. The melting of glaciers and ice sheets is causing the ground in Iceland and Greenland to rise. It is also increasing the risk of earthquakes and volcanic activity in the two countries.