Such gases, mainly CO2 from the burning of fossil fuels, rose on average by 2.2 per cent a year in 2000-2010, driven by the use of coal in the power sector, officials said as they launched the Intergovernmental Panel of Climate Change's report on measures to fight global warming.
Without additional measures to contain emissions, global temperatures will rise about 3 degrees to 4 degrees Celsius (5 degrees to 7 degrees Fahrenheit) by 2100 compared to current levels, the panel said.
"But despite that, the point I'm making is that even now, the cost is not something that's going to bring about a major disruption of economic systems. It's well within our reach."
The IPCC, an international body assessing climate science, projected that shifting the energy system from fossil fuels to zero- or low-carbon sources including wind and solar power would reduce consumption growth by about 0.06 percentage points per year, adding that that did not take into account the economic benefits of reduced climate change.
The IPCC said the shift would entail a near-quadrupling of low-carbon energy, which in the panel's projections included renewable sources as well as nuclear power and fossil fuel-fired plants equipped with technologies to capture some of the emissions.
Coal emissions have declined in the US as some power plants have switched to lower-priced natural gas but they are fueling economic growth in China and India.