Inhabitat: Scientists from the Met Office Hadley Centre and Scripps Institution of Oceanography scrutinized data from NOAA’s Mauna Loa Observatory in Hawaii and forecasted that levels would not dip below 400ppm for ‘our lifetimes.’ by Lacy Cooke
'According to the UN’s Intergovernmental Panel on Climate Change (IPCC), CO2 concentrations of “about 450ppm or lower are likely to maintain warming below 2 degrees Celsius over the 21st century relative to pre-industrial levels.” But lead author on the paper Richard Betts said we could pass that number in 20 years or less. He told the Guardian that even if we reduce emissions immediately, we might be able to delay reaching 450ppm but “it is still looking like a challenge to stay below 450ppm.”
'Paper co-author Ralph Keeling said, “Back in September last year, we suspected that we were measuring CO2 concentrations below 400ppm for the last time. Now it is looking like this was indeed the case.”
'El Niño has played a role in climbing carbon dioxide levels, but we’ll likely see higher CO2 levels than the last large El Niño storm during 1997 and 1998 because “manmade emissions” have risen by 25 percent since that storm, according to The Guardian.'
"El Niño and a record CO2 rise" by Richard A. Betts, et al, here