One indication that we may be outstaying our planetary welcome is the spike in atmospheric greenhouse gases in 2013. Part of that reflects our increased use of fossil fuels. The other part is more worrisome by an order of magnitude.
The Earth, it seems, may have had its fill of absorbing our emissions.
Concentrations of nearly all the major greenhouse gases reached historic highs in 2013, reflecting ever-rising emissions from automobiles and smokestacks but also, scientists believe, a diminishing ability of the world's oceans and plant life to soak up the excess carbon put into the atmosphere by humans, according to data released on Tuesday by the United Nations' meteorological advisory body.
The latest figures from the World Meteorological Organization's monitoring network are considered particularly significant because they reflect not only the amount of carbon pumped into the air by humans, but also the complex interaction between man-made gases and the natural world. Historically, about half of the pollution from human sources has been absorbed by the oceans and terrestrial plants, preventing temperatures from rising as quickly as they otherwise would, scientists say.
"If the oceans and the biosphere cannot absorb as much carbon, the effect on the atmosphere could be much worse," said Oksana Tarasova ...chief of the WMO's Global Atmospheric Watch program.
"The changes we're seeing are really drastic," Tarasova said. "We are seeing the growth rate rising exponentially."
The long and the short of it is that, if our biosphere is losing its capacity to backstop us on our carbon emissions, then even the most radical emissions reductions targets - which we're not even close to meeting - are dangerously inadequate.
"It's the level that climate scientists have identified as the beginning of the danger zone," said Michael Oppenheimer, a Princeton University professor of geosciences who was not involved in the WMO report. "It means we're probably getting to the point where we're looking at the 'safe zone' in the rearview mirror, even as we're stepping on the gas."
The WMO report also incorporated data on ocean acidification stemming from our greenhouse gas emissions. The data shows the rate of acidification is unprecedented over at least the last 300,000 years. Given that every second breath you take represents oxygen generated by our oceans you might want to pay attention to this little problem.
