Carbon dioxide emissions are expected to increase
In the U.S. Energy Information Administration's International Energy Outlook 2013 Reference case, which does not assume new policies to limit greenhouse gas emissions, world energy-related carbon dioxide emissions increase from 31.2 billion metric tons in 2010 to 36.4 billion metric tons in 2020 and 45.5 billion metric tons in 2040. Much of the growth in emissions is attributed to developing countries that are not members of the Organization for Economic Cooperation and Development (OECD) that continue to rely heavily on fossil fuels to meet fast-paced growth in energy demand. Non-OECD carbon dioxide emissions total 31.6 billion metric tons in 2040, or 69% of the world total. In comparison, OECD emissions total 13.9 billion metric tons in 2040, or 31% of the world total.
The United States, with 4% of the world's population, produced about 17% of global carbon dioxide emissions from burning fossil fuels in 2011, the most recent year for which global data are available. The United States accounts for this share primarily because the U.S. economy is the largest in the world and meets 83% of its energy needs by burning fossil fuels.