Reuters: The Group of Eight major economies have agreed that a rise in global temperatures should not exceed 2 degrees Celsius (3.6 Fahrenheit), a European source said on Wednesday following G8 climate talks. "The top line that has been agreed is 2 degrees. It will be in the final G8 draft," the source said, declining to be named. Environmental experts have said that if such a target is taken seriously it will force deep cuts in greenhouse gas emissions.