Guardian: World leaders must commit themselves to holding current rises in global temperatures to 2C. That is the stark message of experts and campaigners in the runup to the United Nations climate summit that will be held in New York later this week.
They say that 2C is the maximum temperature increase that the world can tolerate without causing environmental mayhem, and they insist that politicians attending the meeting, including Barack Obama and David Cameron, must agree to that upper limit.
"If...