Greenhouse gas levels in the atmosphere reached a record high in 2014 as the relentless fuelling of climate change makes the planet more dangerous for future generations, the World Meteorological Organization (WMO) said on Monday (9 November). The rise in carbon dioxide levels was being amplified by higher levels of water vapour, which were in turn rising because of carbon dioxide emissions, the WMO said.

"We have broken a new record once again − over the last 25 years, between 1990 and 2014, there was a 36% increase in the radiative forcing of greenhouse gases," WMO Secretary-General Michel Jarraud told a news conference in Geneva.

Graphs issued by the United Nations (UN) agency showed levels of carbon dioxide, the main greenhouse gas, climbing steadily towards the 400 parts per million (ppm) level, having hit a new record every year since reliable records began in 1984. Carbon dioxide levels averaged 397.7ppm in 2014 but briefly breached the 400ppm barrier in the northern hemisphere in early 2014, and again globally in early 2015. Soon 400ppm will be a permanent reality, Jarraud said.

"Every year we say that time is running out and this year just adds to this pressure and it's very important that these figures are taken into account by the negotiators," Jarraud said.

Levels of the other two major man-made greenhouse gases, methane and nitrous oxide, also continued to rise in 2014, reaching 1,833 parts per billion (ppb) and 327.1ppb, respectively. Both increased at the fastest rate for a decade.

The UN panel of climate scientists estimates that concentrations of carbon dioxide, methane and nitrous oxide are at their highest in at least 800,000 years. Jarraud's annual plea for the world to do whatever it can to cut greenhouse gas emissions comes weeks before negotiators from more than 190 countries are due to meet in Paris to try to agree a new UN climate deal.

Plans revealed so far will not curb emissions enough to meet a target agreed in 2010 − to limit global warming to within 2C of pre-industrial levels.

"Even 1.5 degrees is virtually impossible any longer and certainly 2 degrees is still feasible but it requires quick and strong action," Jarraud said.