Such radical gyrations in the climate are already causing unseen suffering and hardship for countless of the earth's inhabitants. Millions of people have been displaced from their homes or lost their livelihoods as a result of one degree of warming.
All is not lost, researchers warn, but we need to act swiftly.
Rapidly rising temperatures already have had an "amazing and potentially troubling" impact in the Arctic, a group of scientists
According to a paper published Thursday in Science, that melting could come sooner, and be more widespread, than experts