By Chris Mooney / The Washington Post
For the first time since humans have been monitored, the environmental impact of carbon dioxide has increased
The reading from the Mauna Loa Observatory in Hawaii finds that the climate-warming gas is about 400 parts per million throughout April.
Carbon dioxide concentrates – whose "greenhouse gas effect" traps heat and climate change – were around 280 parts per million circa 1880 , at the dawn of the industrial revolution. They're now 46 percent higher.
Concentrations have ticked upward in unbroken progression for many decades.
The rate of growth is about 2.5 parts per million per year, said Ralph Keeling, who directs the CO2 program at the Scripps Institution of Oceanography, which monitors the readings. The rate has increased with the decade of the 201
"It's another milestone in the upward increase in CO2 over time," Keeling said of the newest measurements. "It puts us closer to some targets we do not really want to get to, like getting over 450 or 500 ppm. That's pretty much dangerous territory. "
In a statement on the milestone, Katharine Hayhoe, a climate scientist at Texas Tech University, said," As a scientist, it is not true
Planetary Carbon Dioxide Levels have been high or even higher in the planet's history – but it has been a long time.
In the mid-pliocene warm period more than 3 million years ago, so they were around 400 parts per million – but Earth's
As a recent federal climate science report (co-authored by Hayhoe) noted, the 400 parts per million carbon dioxide level in Pliocene "Plaocene-like conditions may play out in the decades and centuries ahead of us."
Even farther Back in the Miocene era between 14 million and 23 million years ago, carbon dioxide concentrations in the atmosphere are believed to have reached 500 parts per million. [Antarctica is believed to be extinct on the pliocene.]
Farther back at the Eocene-Oligocene boundary around 34 million years ago, Antarctica is believed
These data are available at: http://en.wikipedia.org.uk
Keeling said that the planet is currently at 1 degree Celsius (1.8 degrees Fahrenheit) – and thus, why Earth is now heading back to a period like the mid-Pliocene or even, perhaps, the Miocene. Above pre-industrial levels, it is not yet committed to a warming of 1.5 or 2 degrees Celsius, but it's getting closer all the time – especially for 1.5 C. "We do not have a lot of headroom," he said.
"It's not going to be a sudden breakthrough, either, "Keeling continued. "We're just moving further and further into dangerous territory."