The amount of greenhouse gases in the atmosphere reached a new record high in 2013, propelled by a surge in levels of carbon dioxide, the World Meteorological Organisation warned today.
The organisation also said that gas-absorbing oceans were hit by "unprecedented" acidification.
The WMO's annual Greenhouse Gas Bulletin injected even greater urgency into the need for concerted international action against accelerating and potentially devastating climate change.
The bulletin showed that between 1990 and 2013 there was a 34 per cent increase in radiative forcing - the warming effect on our climate - because of long-lived greenhouse gases such as carbon dioxide (CO2), methane and nitrous oxide.
In 2013, concentration of CO2 in the atmosphere was 142 per cent of the pre-industrial era (1750), and of methane and nitrous oxide 253 per cent and 121 per cent respectively, researchers said.
The observations from WMO's Global Atmosphere Watch (GAW) network showed that CO2 levels increased more between 2012 and 2013 than during any other year since 1984.
Preliminary data indicated that this was possibly related to reduced CO2 uptake by the Earth's biosphere in addition to the steadily increasing CO2 emissions.
The bulletin reports on atmospheric concentrations - and not emissions - of greenhouse gases. Emissions represent what goes into the atmosphere.
Concentrations represent what remains in the atmosphere after the complex system of interactions between the atmosphere, biosphere and the oceans.
About a quarter of the total emissions are taken up by the oceans and another quarter by the biosphere, reducing in this way the amount of CO2 in the atmosphere.
The ocean cushions the increase in CO2 that would otherwise occur in the atmosphere, but with far-reaching impacts.
The current rate of ocean acidification appears unprecedented at least over the last 300 million years, according to an analysis in the report.
"We know without any doubt that our climate is changing and our weather is becoming more extreme due to human activities such as the burning of fossil fuels," said WMO Secretary-General Michel Jarraud.
"The Greenhouse Gas Bulletin shows that, far from falling, the concentration of carbon dioxide in the atmosphere actually increased last year at the fastest rate for nearly 30 years.
"We must reverse this trend by cutting emissions of CO2 and other greenhouse gases across the board. We are running out of time," said Jarraud.
