Efforts to curb climate might cut world GDP by 4 percent

The costs associated with mitigating climate change might reach 4 percent of the world's economic output by 2030, a United Nations draft on global warming says.

Bloomberg reports many of the solutions, highlighted in the leaked draft, that meet the 3.6 degree Fahrenheit cap on global warming backed by world leaders requires a 40 percent to 70 percent reduction in heat-trapping gases by 2050, from 2010 levels.

According to the report, 2 degrees is still "technically possible and ought to remain the primary policy target" for leaders during the climate negotiations that seek to draft a treaty for 2015, said Bob Ward, of the London School of Economics.

The draft, leaked to Bloomberg, is crucial because it is meant to sway the direction of U.N. negotiations, which 190 countries will participate in.