Global emissions of carbon dioxide from the burning of fossil fuel jumped by the largest amount on record last year, upending the notion that the brief decline during the recession might persist through the recovery.
Emissions rose 5.9 percent in 2010, according to an analysis released Sunday by the Global Carbon Project, an international collaboration of scientists tracking the numbers. Scientists with the group said the increase, a half-billion extra tons of carbon pumped into the air, was almost certainly the largest absolute jump in any year since the Industrial Revolution, and the largest percentage increase since 2003.
The increase solidified a trend of ever-rising emissions that scientists fear will make it difficult, if not impossible, to forestall severe climate change in coming decades.
The researchers said the high growth rate reflected a bounce-back from the 1.4 percent drop in emissions in 2009, the year the recession had its biggest impact.
They do not expect the extraordinary growth to persist but do expect emissions to return to something closer to the 3 percent growth of the last decade, still a worrisome figure that signifies little progress in limiting greenhouse gases. The growth rate in the 1990s was closer to 1 percent.
The combustion of coal represented more than half of the growth in emissions, the report found.
In the United States, emissions dropped by a remarkable 7 percent in the recession year of 2009 but rose by just over 4 percent last year, the new analysis shows. This country is the world's second-largest emitter of greenhouse gases, pumping 1.5 billion tons of carbon into the atmosphere last year.
The United States was surpassed several years ago by China, where emissions grew 10.4 percent in 2010, with that country injecting 2.2 billion tons of carbon into the atmosphere. Carbon dioxide emissions are usually measured by the weight of carbon they contain.
The new figures come as delegates from 191 countries meet in Durban, South Africa, for yet another negotiating session in a global control effort that has been ongoing, with minimal success, for the better part of two decades.
"Each year that emissions go up, there's another year of negotiations, another year of indecision," said Glen P. Peters, a researcher at the Center for International Climate and Environmental Research in Oslo and a leader of the group that produced the new analysis. "There's no evidence that this trajectory we've been following the last 10 years is going to change."
Scientists say the rapid growth of emissions is warming Earth, threatening the ecology and putting human welfare at long-term risk. But their increasingly urgent pleas that society find a way to limit emissions have met sharp political resistance in many countries, including the United States, because doing so would entail higher energy costs.
The new figures show a continuation of a trend in which developing countries, including China and India, have surpassed the wealthy countries in their overall greenhouse emissions. In 2010, the combustion of fossil fuels and the production of cement sent more than 9 billion tons of carbon into the atmosphere, the new analysis found, with 57 percent of that coming from developing countries.
Emissions per person, though, are still sharply higher in the wealthy countries, and they have been emitting greenhouse gases far longer, so they account for the bulk of the excess gases in the atmosphere. The level of carbon dioxide, the main such gas, has increased 40 percent since the Industrial Revolution.
On the surface, the figures of recent years suggest that wealthy countries have made headway in stabilizing their emissions. But Peters pointed out that in a sense, the rich countries have simply exported some of them.
The fast rise in developing countries has been caused to a large extent by the growth of energy-intensive manufacturing industries that make goods that rich countries import.
"All that has changed is the location in which the emissions are being produced," Peters said.
Many countries, as part of their response to the economic crisis, invested billions in programs designed to make their energy systems greener. While it is possible those will pay long-term dividends, the new numbers suggest they have had little effect so far.
The financial crisis "was an opportunity to move the global economy away from a high-emissions trajectory," said a scientific paper about the new figures, released online on Sunday by the journal Nature Climate Change. "Our results provide no indication of this happening."