United States airlines and business aviation will be exempt from a law limiting greenhouse gas (GHG) emissions. In an 11th hour move, the House struck aviation from the requirement to cut carbon dioxide emissions by one-third as early as 2012. Reportedly, the change of heart resulted from a report from the Government Accountability Office that said aviation accounts for 2 percent of human-generated GHG. (General aviation is said to generate about 1 percent of that amount.) With such low levels of emissions to start with, it was considered unlikely that such a large percentage of reductions could be achieved without crippling the industry.