Global carbon dioxide emissions hit a new record in 2012, standing at 31.6 billion tons, the IEA reported Monday.
The agency said the energy sector accounts for about two-thirds of global emissions of CO2 and other greenhouse gases, which scientists say are fueling climate change.
The IEA report, presented in London, singles out China as the biggest polluter. Its emissions in 2012 rose 3.8 percent compared to the previous year.
While the Asian country spewed out 300 million tons last year, the gain was one of its lowest seen in decades, reflecting China's efforts to adopt renewable sources of energy and to improve efficiencies.
The IEA said the United States had reduced its year-on-year emissions by 200 million tons, or 3.8 percent, in part due to a switch in power generation from coal to gas. That switch brought the US back to levels last recorded in the mid-1990s.
Emissions in Europe declined over the same period by 50 million tons, or 1.4 percent, because of the continent's protracted economic slowdown and in spite of an increased use of coal-fired power stations overall.
By contrast, Japan's carbon dioxide emissions jumped by 70 million tons in 2012 as endeavors to improve energy efficiency failed to offset its increasing use of fossil fuels in the wake of the Fukushima nuclear disaster in 2011.
Warming to exceed 2-degrees target
The IEA warned that the world was on a path to an average temperature rise of between 3.6 and 5.3 degrees Celsius - about double the target set at a UN summit in Durbin in 2010. Emissions in 2012 were projected to be nearly 4 billion tons higher than a level consistent with attaining the 2-degree target, the agency concluded.
"Climate change has quite frankly slipped to the back burner of policy priorities. But the problem is not going away - quite the opposite," said IEA Executive Director Maria van der Hoeven. "Much more can be done to tackle energy-sector emissions without jeopardising economic growth."
The report said emissions could be reduced significantly by 2020 by improving energy efficiency in buildings, industry and transport, limiting the use of coal-fired power plants, halving the oil and gas industry's release of methane, and phasing out fossil fuel subsidies.
Climate negotiators meeting since last week in Bonn, Germany, are debating the details of a proposed new global climate treaty that is supposed to be adopted by 2015. The main sticking point is how to divide the burden of emissions cuts between developed and developing countries.
hg/ipj (AP, dpa, Reuters)