Atmospheric scientists have warned that carbon dioxide emissions are increasing more rapidly, despite international efforts to curb the use of fossil fuels.
They have found the amount of carbon dioxide being pumped into the atmosphere has doubled in the past 20 years.
CSIRO scientists have found global carbon dioxide emissions reached almost eight billion tonnes last year.
New data from the Cape Grim air pollution monitoring station in north-west Tasmania shows carbon dioxide emissions have increased by 2.5 per cent each year for the past five years.
Atmospheric scientist Paul Fraser says the increase in carbon dioxide comes mostly from developing countries and temperatures will continue to rise.
"Over the last 20 or so years the rate of increase of carbon dioxide in the atmosphere has almost doubled," he said.
"It started off 20 odd years ago at one part per million per year and it's now up to two.
"Once we start reducing emissions, just what level of greenhouse gases the atmosphere will stabilise at is difficult to say.
"But I'm afraid it will be relatively high, which means something like a two degree warming over the next 100 years."
CO2 BubblesAtmospheric scientists warn that greenhouse gas emissions are increasing more rapidly, despite global efforts to curb the use of fossil fuels, new research by Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO) shows.

According to CSIRO research scientist Dr Mike Raupach, 7.9 billion tonnes of carbon were emitted into the atmosphere as carbon dioxide in 2005 -  a doubling in the rate of increase since 1990 - and the rate of increase continues to accelerate.

Data from the Cape Grim air pollution monitoring station in north-west Tasmania shows carbon dioxide emissions have increased by 2.5% each year for the past five years. "From 2000 to 2005, the growth rate of carbon dioxide emissions was more than 2.5% per year, whereas in the 1990s it was less than 1% per year," Dr Raupach says. 

Dr Raupach, who co-chairs the international  Global Carbon Project also, was surprised by his research results. "It shows recent efforts globally to reduce emissions have had little impact on emissions growth," he said. The CSIRO found that in global terms, China has the highest current growth rate in CO2 emissions although it's emissions per person are below the global average. China's accumulated contribution since the start the 1800s is only five per cent of the global total. The USA and Europe have each contributed more than 25% of accumulated global emissions. 

Carbon dioxide concentrations in the atmosphere — a separate measure to carbon emissions — had also increased at an unprecedented rate. Dr Paul Fraser, also from CSIRO Marine and Atmospheric Research, said that atmospheric concentrations of carbon dioxide grew by two parts per million in 2005, the fourth year in a row of above-average growth. "To have four years in a row of above-average carbon dioxide growth is unprecedented," Dr Fraser said. 

He said the trend over recent years suggests the growth rate is accelerating, "signifying that fossil fuels are having an impact on greenhouse gas concentrations in a way we haven’t seen in the past."