The level of carbon dioxide in the atmosphere rose by a record rate last year, reaching levels that have in the past been associated with global temperatures 2 to 3 degrees warmer and sea levels 10 to 20 metres higher than present, according to the World Meteorological Organization.

The WMO released its annual Greenhouse Gas Bulletin on Monday, showing CO2 levels surged by 3.3 parts per million in 2016 to an average level of 403.3 ppm. Such a level is comparable to conditions 3 to 5 million years ago.

Last year's increase was driven by human activities, such as burning of fossil fuels, and the strong El Nino event in the Pacific.

"From the most-recent high resolution reconstructions from ice cores, it is possible to observe that changes in CO2 have never been as fast as in the past 150 years, and the natural ice-age changes in CO2 have always preceded corresponding temperature changes," the bulletin said, noting the rate of increase was almost 100 times faster than at the end of the last ice age.