Greenhouse gas report reveals record CO2 levels

Heat-trapping gases in the atmosphere reached record levels in 2015, UN climate experts said Monday, and they've warned that things are likely to stay that way for generations to come.
Droughts caused by the El Niño weather phenomenon are credited with reducing how much carbon dioxide the earth can absorb. Photo: OCHA/Tamara van Vliet.
According to a new report from the World Meteorological Organization (WMO), the El Niño weather phenomenon was most to blame.

The droughts it triggered limited the earth's capacity to absorb carbon dioxide – the gas responsible for most global warming.

Here's Daniel Johnson in Geneva.

For weather-watchers, 2015 will be remembered for the historic Paris agreement on climate action, which saw nations take a united stand to reduce global warming.

But for the UN's World Meteorological Organization (WMO), last year was also marked by record concentrations of the invisible emissions that drive climate change, otherwise known as greenhouse gases.

For the first time on record, the main culprit – carbon dioxide, or CO2 – passed 400 parts per million in 2015.

Here's Petteri Taalas, WMO Secretary-General:

"So the bad news when it comes to CO2 is that it's lifetime is very long, and a return to pre-industrial levels may take tens of thousands of years."

Latest data shows that levels of carbon dioxide are now 144 per cent higher than they were in 1750.

Other harmful gases are also at record levels, including nitrous and methane, which was 256 per cent higher last year than in pre-industrial times.

While many factors are at play when it comes to climate change, the El Niño weather phenomenon is credited with fuelling the spike in global warming from CO2.

It began in 2015 and continued into 2016, triggering droughts in tropical regions, which in turn reduced how much greenhouse gases were absorbed.

And in a call for urgent action, WMO warns that these so-called "carbon sinks" risk becoming saturated, leading to a further increase in CO2 emissions.

Daniel Johnson, United Nations, Geneva.