London, Sep 22 (IANS): Ahead of the New York Climate Summit, researchers have revealed that carbon dioxide (CO2) emissions, the main contributor to global warming, is set to rise again in 2014 - reaching a record high of 40 billion tonnes.

The world leaders will meet at the UN headquarters in New York Tuesday to galvanise and catalyse action on climate change.

The CO2 emissions from burning fossil fuel are projected to rise by 2.5 percent in 2014 - 65 percent above 1990 levels, the reference year for the Kyoto Protocol, the findings showed.

"The human influence on climate change is clear. We need substantial and sustained reductions in CO2 emissions from burning fossil fuels if we are to limit global climate change," said Corinne Le Quere, a professor at Tyndall Centre for Climate Change Research at the University of East Anglia in Britain.

This latest annual update of the Global Carbon Budget shows that total future CO2 emissions cannot exceed 1,200 billion tonnes - for a likely 66 percent chance of keeping average global warming under 2 degrees celsius (since pre-industrial times).

At the current rate of CO2 emissions, this 1,200 billion tonne CO2 quota would be used up in around 30 years.

This means that there is just one generation before the safeguards to a CO2 limit may be breached.

To avoid this, more than half of all fossil fuel reserves may need to be left unexploited, the researchers noted.

"We are nowhere near the commitments necessary to stay below 2 degrees celsius of climate change, a level that will be already challenging to manage for most countries around the world, even for rich nations," Le Quere noted.

The study appeared in the journal Nature Geoscience.