text: But let's not stop there. Let's use our imagination and assume that China reduces its emissions by 20 percent by 2030. That gets us two tenths of a degree. Throw in a 30 percent reduction by Europe and Japan and the rest of the industrialized world, also by 2030. That's another two tenths of a degree, for a grand total of 0.425 degrees, under a "climate sensitivity" (loosely, the effectiveness of greenhouse gas reductions) assumption 50 percent greater than that adopted by the Intergovernmental Panel on Climate Change in its latest assessment report. Is an effect that small worth 1 percent of global GDP, or roughly $600 billion to $750 billion per year, inflicted disproportionately upon the world's poor?