Global emissions of carbon dioxide declined slightly in 2009, but the beginnings of economic recovery led to an unprecedented emissions increase of 5.8 % in 2010. In 2011, global atmospheric levels of CO₂ reached a high of 391.3 parts per million (ppm), up from 388.6 ppm in 2010 and 280 ppm in pre-industrial times, according to new research conducted by the Worldwatch Institute for its Vital Signs Online.

More than 70 % of CO₂ emissions result from the burning of fossil fuels for energy use, such as electricity generation, transportation, manufacturing, and construction. In 2009, electricity generation and heating alone accounted for 41 % of all energy related CO₂ emissions.

Emissions increases in both industrialized and developing economies. Member states of the Organisation for Economic Co-operation and Development (OECD) increased their emissions by 3.4 % in 2010, while countries outside the OECD saw an increase of 7.6 %.
China was the world’s largest overall emitter in 2010 followed by the United States, India, and Russia. China ranks only 61st in terms of the CO₂ emitted per person, India ranks far below the world average, and the United States, in contrast, ranks 10th in per capita emissions.

Global CO₂ levels are now 45 % above the 1990 level, which serves as the reference base year for the United Nations Framework Convention on Climate Change. Several Annex I countries—including the United States, which signed but never ratified the Kyoto Protocol—will be unable to meet their original reductions targets. Since December 2011, Canada, Japan, and Russia, have chosen not to take on additional emissions targets within the second commitment period of Kyoto Protocol in the coming decade.

•  Worldwatch Institute, Washington, DC, USA