Record carbon dioxide concentrations in the atmosphere were reported worldwide in March, in what scientists said marked a significant milestone for global warming. Figures released by the US science agency Noaa on Wednesday show that for the first time since records began, the parts per million (ppm) of CO2 in the atmosphere were over 400 globally for a month.
The measure is the key indicator of the amount of planet-warming gases man is putting into the atmosphere at record rates, and the current concentrations are unprecedented in millions of years. The new global record follows the breaking of the 400ppm CO2 threshold in some local areas in 2012 and 2013, and comes nearly three decades after what is considered the ‘safe’ level of 350ppm was passed.
“Reaching 400ppm as a global average is a significant milestone,” said Pieter Tans, lead scientist on Noaa’s greenhouse gas network.
“This marks the fact that humans burning fossil fuels have caused global carbon dioxide concentrations to rise more than 120ppm since pre-industrial times,” added Tans. “Half of that rise has occurred since 1980.”
World leaders are due to meet in Paris for a UN climate summit later this year in an attempt to reach agreement on cutting countries’ carbon emissions to avoid dangerous global warming.