Huge amounts of frozen methane gas is trapped in the permafrost,it’s being released as the temps rise and the permafrost melts. It’s not just Co2 that’s the problem,the term is greenhouse gases not gas.
They are considering calling polar bears marine mammals because they are spending more time in the water than on land or ice. Up in Churchill the bears are being land locked for up to 6 months,used to be a 3 month stay until the sea ice could support them. They are staving during this time as they can’t feed except for from human garbage. They are considered the most southerly population of polar bears, will be a real shame when they are gone.
I'll start with greenhouse gases. The three biggies are CO2, Water vapor - H2O, and Methane - HC4. It's true, in a sealed environment the quantities of these gases will remain constant. In a free atmosphere, one that contains Ozone, a single Oxygen atom, a free radical, if you will, then the Methane and the Ozone react and break down to water vapor and carbon dioxide. People talk about how rain forests process carbon dioxide, but they never mention that rain forests produce large amounts of methane, which is release when animal or vegetable matter rots.
As for the polar bears, their Latin name is Ursus Maritimus, the sea bear. It's the largest extant bear species and the largest extant land carnivore. I'm not too worried about the polar bears. They just make a 'oh how sad' picture when the iceberg they've been floating begins to break up.