After a fall of global carbon-dioxide (CO2) emissions in 2009, energy-related CO2 emission reached a record high in 2010, up by 5 percent from last record in 2008, according to the latest estimates by the Paris-based International Energy Agency (IEA).

2010 emissions are estimated to have climbed to a record 30.6 Gigatonnes (Gt), while 80 percent of projected emissions from the power sector in 2020 are those unlikely to be changed, the energy agency said.

The last record in 2008 reported CO2 emission in total of 29.3 Gt, which followed by a dip in 2009 due to the global financial recession.

The IEA envisaged 2010 data and potential future emission "a serious setback" to a target of limiting temperature increase to 2 degrees Celsius at the UN climate change talks in Cancun in 2010.

"Our latest estimates are another wake-up call ... The world has edged incredibly close to the level of emissions that should not be reached until 2020 if the 2 degree Celsius target is to be attained," said Fatih Birol, chief economist at the IEA.

To achieve the goal of 2 degrees Celsius limitation, "global energy-related emissions in 2020 must not be greater than 32 Gt. This means that over the next 10 years, emissions must rise less in total than they did between 2009 and 2010," the energy watchdog said in a press release.

"Given the shrinking room for maneuver in 2020, unless bold and decisive decisions are made very soon, it will be extremely challenging to succeed in achieving this global goal agreed in Cancun," Birol added.

In terms of fuels, according to IEA, 44 percent of the estimated CO2 emissions in 2010 came from coal, 36 percent from oil, and 20 percent from natural gas.

Region by region, the IEA estimated that 40 percent of global emissions came from OECD countries in 2010, while non-OECD emerging economies saw stronger increase in the emission as their economic growth accelerated.

In addition, on a per capita basis, OECD countries collectively emitted 10 tons, more than 5.8 tons in China and 1.5 tons in India.