New York Times: How close is the world to devastating climate upheaval? My column on Wednesday argued that the natural gas boom is helping the United States reduce its emissions of heat-trapping carbon into the air, encouraging power generators to switch to gas from the much dirtier coal. American CO2 emissions last year totaled about 5.25 billion tons -- almost 13 percent less than in 2007. But as some readers argued, the decline is so modest that it is almost irrelevant. To stop the worlds temperature from rising...