The world is on track to warm by a whopping 6 degrees Celsius by the end of this century, scientists have said.
According to a report in New Scientist, the estimate was made by the Global Carbon Project, a group of 31 scientists from 7 countries led by Corinne Le Quere at the University of East Anglia and the British Antarctic Survey, who used satellite and national inventory data to track emissions of carbon dioxide (CO2).
They also used models to estimate carbon sinks - such as oceans and forests - that absorb the greenhouse gas.
It found that the ability of natural carbon sinks to soak up the CO2 humans pump into the atmosphere is declining.
The study estimates that in the past 50 years, the fraction of CO2 emissions that remains in the atmosphere each year may have increased from roughly 40 per cent to 45 per cent.
As a result, the portion of emitted CO2 that ends up staying in the atmosphere increased on average by around 0.3 per cent per year between 1959 and 2008.
According to the study, CO2 emissions from the burning of fossil fuels have increased at an average annual rate of 3.4 per cent between 2000 and 2008, compared with just 1 per cent per year in the 1990s, mainly as a result of the boom in China's economy.
Between 2000 and 2008, global emissions rose by 29 per cent.
"If steps are not taken at the climate change discussions in Copenhagen this December to rein in runaway emissions, the world is heading for a 6C rise," said Le Quere.
"If the agreement is too weak, or the commitments not respected, it is not 2.5 degrees C or 3 degrees C we will get: it's 5 C or 6 C - that is the path we're on," Le Quere said.