The other Arctic tipping point is because the ocean absorbs a lot more energy than ice... so once the Arctic loses more ice cover, it will go ice-free and remai

The other Arctic tipping point is because the ocean absorbs a lot more energy than ice... so once the Arctic loses more ice cover, it will go ice-free and remain that way. Nobody knows when/if the methane problem will happen. The ice/ocean thing can be modeled.