Strange holes are appearing in the ground in parts of remote Siberia. Scientists are becoming more concerned as these holes release more greenhouse gases into the air, which may result in an increase in global warming.

The first hole appeared several weeks ago in an isolated region of northern Russia and is nearly 230 feet deep. This week, two reindeer herders discovered two more holes in the large region, which is mostly made up of permafrost (long-term frozen soil).

After studying the first hole, scientists found an icy lake at the bottom, suggesting that the chasm is a result of ice melting underneath the permafrost. This process releases carbon-based gases, such as carbon dioxide and methane, that builds up enough pressure to break through the frozen soil. Some of those gases are then released into the Earth's atmosphere.

The gases released by the holes aren't necessarily harmful to the human population, especially since these sinkholes are occurring in remote regions. However, according to some environmental scientists, these holes represent a frightening trend. Not only are scientists concerned with global warming melting the ice underneath the permafrost, but the release of the gases could potentially add to the greenhouse gases already in our atmosphere, creating even higher temperatures around the world. When permafrost melts, most of the gas released is methane, which is 20 times stronger than carbon dioxide.

With rising global temperatures, more of the Earth's permafrost is sure to melt. Kevin Schaefer, a scientist with the National Snow and Ice Data Center, believes that the Arctic might eventually fall into a dangerous cycle.

"If the Arctic permafrost releases more carbon than it absorbs, it would start a cycle where the extra carbon in the atmosphere leads to increased warming," he says. "The increased warming means more permafrost thawing and methane release."

There is good news, though. We haven't yet reached that point. Scientists are researching the amount of carbon present in permafrost, with hopes of discovering the specific amounts of carbon dioxide and methane that might be released when it melts. With that knowledge, scientists could figure out how to lessen the impact on the environment.