The sonar image above shows methane bubbles being released by the Arctic Ocean floor. As the water temperature increases due to climate change, methane is released by the reserves of methane hydrate beneath the sea bed.
Methane is one of the gases that cause the greenhouse effect and it is far more harmful than CO2 (20 times more damaging). It is estimated that nearly 20 megatons of methane are being released each year by this hydrate deposit, located near Norway.
In addition to that, the melting of the permafrost in Arctic regions has a similar effect. The permafrost covers about 25% of the earth's land area and stores large amounts of organic carbon.
That is the size of the problem.