A new study by NOAA's Earth System Research Lab finds: Greenhouse gases likely accounted for more than half of the widespread warmth across the continental United States last year ... [T]he probability of U.S. temperatures breaking a record in 2006 had increased 15-fold compared to pre-industrial times because of greenhouse gas increases in Earth's atmosphere. How did they come to this conclusion? [T]he NOAA team analyzed 42 simulations of Earth's climate from 1 ...