Global emissions of carbon dioxide show no signs of abating and might reach record levels in 2010, according to a new study led by the University of Exeter. Carbon dioxide is the primary cause of global warming and is chiefly emitted by the burning of fossil fuels. The study found that if economic growth proceeds as expected, global fossil fuel emissions will increase by more than 3% in 2010, approaching the high emissions growth rates observed in 2000–2008.
The Exeter study also re-examined global carbon dioxide emissions in 2009 and found that they decreased less than expected, dropping only 1.3% below the record figures recorded in 2008. Although the recession caused most industrialized countries to experience sharp drops in carbon dioxide emissions in 2009 (including a 7% drop in the United States), many developing countries recorded substantial increases. For example, China's carbon dioxide emissions increased by 8%, while India's rose by 6.2%. Those nations also produce more carbon dioxide per unit of gross domestic product (a measure referred to as the "carbon intensity" of the economy), so their economic growth resulted in greater emissions than would a similar rate of growth in developed countries. See the University of Exeter press release and an article from the EERE Network News on U.S. energy-related carbon dioxide emissions in 2009.
Concentrations of carbon dioxide measured in Earth's atmosphere also continued to increase in 2009, according to the National Oceanic and Atmospheric Administration (NOAA). NOAA found that the mean growth in carbon dioxide concentrations in 2009 (after averaging out seasonal fluctuations) was 1.62 parts per million (ppm), compared with 1.66 ppm in 2008. NOAA's latest update of its greenhouse gas index, released in early September, found that atmospheric concentrations of carbon dioxide, nitrous oxide, and methane all continued to rise in 2009. As a result, the "radiative forcing" of Earth's atmosphere—that is, the strength of Earth's greenhouse effect—increased by 1% in 2009, compared to 1.3% in 2008. Since 1990, the global radiative forcing has increased by 27.5%. See NOAA's trends in atmospheric carbon dioxide and annual greenhouse gas index Web sites.