The world has less than 12 years to go before it faces major ice-melting and potentially catastrophic effects if nothing is done to reduce carbon emissions, a Thai environmental conservationist has warned.

Energy and environmental conservationist Chirapol Sintunawa said it would take approximately that time for the carbon dioxide (CO2) in the atmosphere to reach the 450 parts per million (ppm) figure, which would cause temperatures to rise and ice to melt, increasing sea levels.

"At present, the atmospheric CO2 is about 392ppm. The Earth can ideally withstand only 350ppm of CO2, which is considered the safe level by many scientists, including Nasa climate scientist James Hansen," said the professor from Mahidol University in Thailand.

Worldwide campaigns have been ongoing as far as Siberia to create awareness of the 350 target, the Star paper quoted him as saying.

"The global warming effect will see global temperatures rising by 2 degree Celsius at 450ppm. This means ice in the North and South Poles will start melting more. We must act now to reduce carbon and protect the environment," said Chirapol at Warisan Global's Go green with e.n.v.y: A GreenTech Entrepreneurship and Networking Session.

Preliminary data by the US National Oceanic and Atmospheric Administration (NOAA) showed the carbon dioxide figure stood at 392.04ppm as of June this year. It was 389.43ppm in 2009 and 387.88ppm in 2008, he said.

He deduced it would take less than 12 years to reach the 450ppm level.