The U.S. emitted 20 percent of the world’s global-warming gases from 1750 through 2005, and China accounted for 12 percent, according to a group of scientists.
The association known as Match, which models and assesses contributions to climate change, said it showed for the first time how assessments over different timeframes and various industries change the estimate of national contribution.
The Match database shows that China is overtaking the U.S. in terms of emissions. United Nations talks have stalled over targets after limits for richer nations in the 1997 Kyoto Protocol expire in 2012. Almost 200 nations are meeting later this month in Cancun, Mexico, to try and reach an agreement to limit greenhouse gases blamed for climate change.
China, with a population of 1.4 billion people, will be responsible for 16.2 percent of the world’s emissions in the three decades through 2020, the research and Bloomberg data show. That compares with 15.7 percent for the U.S., which has 322 million people.
Based on energy and industry emissions only for the period from 1990 through 2020, which ignores agriculture and land-use gases, the U.S. contribution rises to 19.9 percent, outstripping China’s at 17.8 percent, the research shows.
The research shows that developing nations probably won’t track the carbon intensity of richer nations, especially those that were first to industrialize, such as Britain, Niklas Hoehne who heads the MATCH support unit at Ecofys Group in Cologne, Germany, said today in a phone interview. Carbon intensity is a measure of how much greenhouse gas is produced for each unit of economic output.
No longer necessary
Coal-based economic development “is not necessary anymore,” Hoehne said. The U.K. had 6.5 percent of the world’s energy and industry emissions in the period from 1750 through 2005, according to Match data. In the period from 1990 through 2005, Britain emitted 2.4 percent of global output, it shows.
The research demonstrates the uncertainty in current data. The U.S.’s accumulated contribution through 2005 from 1750 may be as much as 28 percent and as low as 16 percent, it said.
In the six decades through 2050, China will contribute most of the world’s emissions, or 17.6 percent. That compares with 12.1 percent for the U.S. and 8.2 percent for India, according to the data, which relies on previously published data from the Intergovernmental Panel on Climate Change, the UN’s climate- science group.
