Source: The Age (AFP)
Date: 12 May, 2013
The level of carbon dioxide in the atmosphere has surpassed 400 parts per million for the first time in human history, US monitors say, sparking new calls for action to scale back greenhouse gases.
Climate scientists say the threshold is largely symbolic and has been expected for some time, but warn that it serves as an important message that people need to reverse the damage caused to the environment by the heavy use of fossil fuels. The Earth has not seen these levels of carbon dioxide in 3 million to 5 million years, long before humans existed, when temperatures were several degrees warmer and the sea level was 20 metres to 40 metres higher than today, experts say.
”We are creating a prehistoric climate in which human societies will face huge and potentially catastrophic risks,” said Bob Ward, policy director at the Grantham climate change institute at the London School of Economics and Political Science. ”Only by urgently reducing global emissions will we be able to bring carbon dioxide levels down and avoid the full consequences of turning back the climate clock.”
Data showing daily average carbon dioxide over the Pacific Ocean was 400.03 parts per million on May 9 was posted online by the National Oceanic and Atmospheric Administration’s centre in Hawaii. A monitor at the Scripps Institution of Oceanography in San Diego, California, recorded 400.08 parts per million.
Michael Mann, director of the Earth System Science Centre at Pennsylvania State University, said: ”There is no precedent in Earth’s history for such an abrupt increase in greenhouse gas concentrations.”