The Earth’s climate will enter a new “permanent reality” from next year when concentrations of CO2 in the atmosphere are likely to pass a historic milestone, the head of the UN’s weather agency has warned.
The record concentrations of CO2 in the atmosphere were up 43% since pre-industrial times, said the World Meteorological Organization (WMO), prompting its secretary general Michel Jarraud to say immediate action was needed to cut CO2 emissions.
The WMO’s latest greenhouse gas bulletin comes just three weeks before world leaders including Barack Obama, Xi Jinping and David Cameron meet in Paris in a bid to reach a new deal on cutting emissions.
Concentrations of CO2 stood at a global annual average of 397.7ppm in 2014, up from about 278ppm in 1750, and the UN said the global annual average is likely to pass the symbolic 400ppm milestone in 2016. Scientists say that the ‘safe’ level of CO2 to avoid dangerous global warming is more like 350ppm.
“We will soon be living with globally averaged CO2 levels above 400 parts per million as a permanent reality,” said Jarraud.
“We can’t see CO2. It is an invisible threat, but a very real one. 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,” he said.
The increase in CO2 concentrations from 2013 to 2014 was 1.9ppm CO2, slightly lower than the mean for the last decade of 2.06ppm, but higher than the 1990s mean of 1.5ppm.
The WMO also warned that the rising Earth surface temperature caused by these record CO2 concentrations created a vicious circle when it comes to water vapour. Higher temperatures lead to more atmospheric water vapour, which in turn traps even more heat.
Jarraud said that each year he announced new records for CO2 concentrations and that to keep temperatures within manageable levels, CO2 emissions from factories, cars and power plants needed to be cut now. “The laws of physics are non-negotiable,” he said.
