Associated Press: In its first major climate report to the United Nations in four years, the United States reported Tuesday that its projected climate-warming greenhouse gases will grow by 4 percent through 2020. The first such report submitted under the Obama administration includes a 1.5 percent rise in carbon dioxide emissions, the main gas from fossil fuel burning blamed for global warming. But it’s the culpability of hydrofluorocarbons, or HFCs — promoted worldwide to replace chemicals …