"Energy-related carbon-dioxide (CO2) emissions in 2010 were the highest in history, according to the latest estimates," the International Energy Agency (IEA) said in a statement.

After a dip in 2009 caused by the global financial crisis, emissions are estimated to have climbed to a record 30.6 gigatonnes (Gt), a five percent jump from the previous record year in 2008, when levels reached 29.3 Gt, the IEA said.

Moreover, the IEA estimated that 80 percent of projected emissions from the power sector in 2020 are already locked in, as they will come from power plants that are currently in place or under construction today.

"This significant increase in CO2 emissions and the locking in of future emissions due to infrastructure investments represent a serious setback to our hopes of limiting the global rise in temperature to no more than two degrees C," said Fatih Birol, the IEA's chief economist.

Global leaders agreed a target of limiting temperature increase to two degrees C at UN climate change talks in Cancun, Mexico last year.

For this goal to be achieved, the long-term concentration of greenhouse gases in the atmosphere must be limited to around 450 parts per million of CO2-equivalent, only a five percent increase compared to an estimated 430 parts per million in 2000.

The IEA has calculated that in order to achieve this level, based on emissions targets countries have agreed to reach by 2020, that global energy-related emissions in 2020 must not be greater than 32 Gt.