Man-made greenhouse gases account for about 3.2 percent of the total (see Table 1). Even if man-made greenhouse gases were cut by 50 percent (sending us back to pre-industrial revolution levels), that would be just 1.6 percent. On top of that, the sun's energy output is more important than greenhouse gases. If greenhouse gases make up 25 percent of the causes, man's share of the effect falls to 0.8 percent and a 50 percent cut in that reduces the impact to just 0.4 percent. Of course, there is also the issue of temperature changes driving changes in carbon dioxide and not the other way around, but the main point is already clear.