May 2020 has broken the historical record for hottest month of May worldwide. While worrisome, this unprecedented heat also threatens to unleash billions of tons of frozen carbon dioxide stored in the thawing permafrost in Siberia.

Permafrost is ground that remains continuously frozen for two or more years. It holds together different sorts of soil, sand, and rocks. More ominously, the permafrost in Russia and Canada contains some 1.5 trillion metric tons of CO2. This massive amount is more than 40 times the CO2 emissions pumped into the atmosphere by human activity.

The European Union's Copernicus Climate Change Service (C3S) reported temperatures in Siberia rising 10 degrees Celsius (18 degrees Fahrenheit) above their normal levels in May.

Worldwide, May was 0.63°C warmer than the average May temperature between 1981 and 2010. This feat made May 2020 the warmest May in this data record, said C3S.

Other discomforting statistics about May's historic temperature rise:

* Globally, May was 0.63°C warmer than the average May from 1981 to 2010, the warmest May in C3S records. The last 12 month period was close to 0.7°C warmer than average, matching the warmest twelve-month period.

* May was warmer by 0.05°C than May 2016, the previous warmest May;

* It was warmer by 0.09°C compared May 2017, the third warmest May.

* The temperature rise in May correlates to a 1.26°C rise on pre-industrial levels.

Because of the 1.26°C spike in May, the world has moved dangerously closer to the temperature threshold of 2°C international organizations warn will be devastating to the Earth if exceeded. Global temperatures must be kept from rising above 1.5°C to avoid major impacts on the climate, according to the United Nations' Intergovernmental Panel on Climate Change (IPCC). The organization says billions of people might live in areas too hot for humans by 2070.

The heat searing Siberia and melting its permafrost, was the direct cause of a massive oil spill in Siberia on June 4 where more than 21,000 tons of diesel fuel oil from a power station was spilled into the pristine Arctic Ocean. The disaster is one of the largest oil spills in Russian history. Russian officials are blaming it on the melting permafrost in the region.

An environmental group described the damage caused by the spill as catastrophic. The concentration of contaminants far exceeds permissible levels tens of thousands of times over.

Two thirds of Russia consists of permafrost, which is degrading rapidly due to global warming. The most visible result of the melting permafrost is the creations of an increasing number of giant sinkholes in Siberia.

The year 2019 saw the hottest winter in the 140-year history of meteorological observations in Russia, according to the state-run Hydrometeorological Center of Russia.