GENEVA, Nov 9 (Reuters) - Greenhouse gas levels in the atmosphere reached a record high in 2014 as the relentless fueling of climate change makes the planet more dangerous for future generations, the World Meteorological Organization said on Monday.
"Every year we say that time is running out. We have to act NOW to slash greenhouse gasemissions if we are to have a chance to keep the increase in temperatures to manageable levels," WMO Secretary-General Michel Jarraud said in a statement.
Graphs issued by the United Nations agency showed levels of carbon dioxide, the maingreenhouse 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 397.7 ppm in 2014 but briefly breached the 400 ppm barrier in the northern hemisphere in early 2014, and again globally in early 2015.
Soon 400 ppm will be a permanent reality, Jarraud said.
"It means hotter global temperatures, more extreme weather events like heatwaves and floods, melting ice, rising sea levels and increased acidity of the oceans. This is happening now and we are moving into uncharted territory at a frightening speed."
The rise in carbon dioxide levels was being amplified by higher levels of water vapor, which were in turn rising because of carbon dioxide emissions, the WMO said.
Levels of the other two major man-made greenhouse gases, methane and nitrous oxide, also continued their relentless annual rise in 2014, reaching 1,833 parts per billion (ppb) and 327.1 ppb, respectively. Both increased at the fastest rate for a decade.
The U.N. 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 U.N. climate deal.
More than 150 countries, led by top greenhouse gas emitters China and the United States, have issued plans to limit greenhouse gas emissions beyond 2020. But the plans revealed so far will not curb emissions enough to meet a target agreed in 2010, to limit global warming to within 2° Celsius (3.6 Fahrenheit) of pre-industrial levels. (Reporting by Tom Miles; Editing by Digby Lidstone)
CORRECTION: This post has been updated to reflect that global CO2 levels are 143 percent of pre-industrial levels, not 143 percent higher.