LONDON: The Earth this year may witness one of the largest increase in atmospheric Carbon Dioxide in over six decades of record keeping, scientists say.

The forecast by researchers from the UK Met Office and University of Exeter is based on a combination of factors including rising anthropogenic emissions and a relative reduction in the uptake of Carbon-dioxide by ecosystems due to tropical climate variability.

"Since 1958, monitoring at the Mauna Loa observatory in Hawaii has registered around a 30 per cent increase in the concentration of carbon dioxide in the atmosphere," said Richard Betts, a professor at University of Exeter.

"This is caused by emissions from fossil fuels, deforestation and cement production, and the increase would have been even larger if it were not for natural carbon sinks which soak up some of the excess CO2," Betts said.

The rise has since become generally faster over time as human emissions have increased, but with fluctuations related to climate swings such as El Nino.

"Looking at the monthly figures, it's as if you can see the planet 'breathing' as the levels of carbon dioxide fall and rise with seasonal cycle of plant growth and decay in the northern hemisphere," said Betts.