Carbon Scenarios report concludes that , ' global warming targets ` ` unrealistic '' Report 's author : ` ` We have failed . We could not prevent varying degrees of warming '' Document explores three scenarios for global warming under different circumstances . There would be a greater than 90 percent chance of global average temperatures rising no more than 4.8 degrees above pre-industrial levels by 2100 . Proposes radical shift in policy to introduce global carbon caps and permits .
Carbon Scenarios report concludes that , ' global warming targets ` ` unrealistic '' Report 's author : ` ` We have failed . We could not prevent varying degrees of warming '' Document explores three scenarios for global warming under different circumstances . Proposes radical shift in policy to introduce global carbon caps and permits .