DOE: CO2 Emissions Growing Rapidly, Especially in Asia

December 4, 2008 // Published as a news service by IHS

Carbon dioxide emissions grew from 6.1 billion metric tons of carbon in 1992 to 8.5 billion metric tons in 2007, with the greatest growth in developing Asian countries such as China and India, according to the ORNL.

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In fact, the U.S. was the largest emitter of carbon dioxide in 1992, but China now leads the pack, according to the ORNL.

These are the findings of an analysis completed by the DOE Carbon Dioxide Information Analysis Center at ORNL.

"The United States was the largest emitter of CO2 in 1992, followed in order by China, Russia, Japan and India," said Gregg Marland of ORNL's Environmental Sciences Division. "The most recent estimates suggest that India passed Japan in 2002, China became the largest emitter in 2006 and India is poised to pass Russia to become the third largest emitter, probably this year."

The latest estimates of annual emissions of carbon dioxide to the atmosphere indicate that emissions are continuing to grow rapidly and that the pattern of emissions changed markedly since the drafting of the U.N. Framework Convention on Climate Change in 1992, according to the analysis. It was then that the international community expressed concern about limiting emissions of greenhouse gases.

In the Kyoto Protocol, 38 developed countries initially agreed to limit their emissions of greenhouse gases in an effort to minimize their potential impact on the earth's climate system.

At the time of drafting the U.N. Convention, those 38 countries were responsible for 62% of carbon dioxide emissions attributable to all countries. By the time the Kyoto Protocol was drafted in 1997, that fraction was down to 57%, according to the analysis.

The recent emissions estimates show that by the time the Kyoto Protocol came into force in 2005, those 38 countries were the source of less than half of the national total of emissions (an estimated 49.7%) and this value as of 2007 was 47%, according to the analysis.

More than half of global emissions are now from the so-called "developing countries," according to the analysis. The Kyoto Protocol was ratified by 181 countries, but not by the U.S. Marland said that these emissions numbers are subject to some uncertainty - about 5% for the U.S., but possibly as much as 20% for China.

"These are our best estimates, but precise numbers cannot be known with certainty," Marland said. "Also, as countries with less certain data become more important to the overall CO2 picture, the estimates of the global total of emissions become less certain."

While this national distribution of emissions is significant in the context of international agreements like the Kyoto Protocol, its practical significance is less clear in a world linked by international commerce, said co-author Jay Gregg of the University of Maryland.

For example, a recent study estimated, that a third of carbon dioxide emissions from China in 2005 were due to production of goods for export.

Current estimates of national carbon dioxide emissions show the amount of carbon dioxide emitted from within a country and do not take into consideration the impact of international trade in goods and services or the energy used in international travel and transport.

The new estimates of carbon dioxide emissions are based on energy data through 2005 from the United Nations, cement data through 2005 from the U.S. Geological Survey, energy data for 2006 and 2007 from BP p.l.c. and extrapolations by Marland, Gregg and co-authors Tom Boden and Bob Andres of ORNL.

Burning fossil fuels and manufacturing cement - along with deforestation - are the most important human-related sources of carbon dioxide emissions to the atmosphere, according to the researchers.

The cement data take into account the breakdown of limestone to produce lime. Researchers also said that the new carbon dioxide data include minor downward revisions of estimates for recent years, but the trends are not changed.

More information about the carbon dioxide analysis is available at the Carbon Dioxide Information Analysis Center web site.

The ORNL study is part of an effort to determine the global carbon budget for 2007, according to the DOE Energy Efficiency and Renewable Energy (EERE) Vehicle Technologies Program. That effort, led by the Global Carbon Project, also looks at carbon emissions from land use changes (such as deforestation) and natural "sinks" for carbon dioxide.

The world's oceans and trees are large carbon sinks, with oceans removing 25% of all carbon dioxide emissions over the past eight years and terrestrial sinks removing another 29%, according to the Global Carbon Project.

The end result is that the fraction of carbon dioxide in the atmosphere is increasing. In fact, it increased by 2.2 parts per million (ppm) in 2007, which was greater than the 2.0 ppm average growth rate for 2000-2007 and well above the growth rate of 1.5 ppm that held for the previous 20 years, according to the Global Carbon Project.

The 2007 increase brought the atmospheric concentration of carbon dioxide to 383 ppm, which is 37% greater than the concentration at the start of the industrial revolution.

According to the Global Carbon Project, the present concentration is the highest in at least 650,000 years and is probably the highest for the last 20 million years.

Source: U.S. Department of Energy Efficiency and Renewable Energy (EERE) Vehicle Technologies Program.