Earth absorbs more of our CO2 emissions
Even as man’s output of earth-warming CO2 has risen, so has the capacity of plants and the oceans to absorb it, scientists said, but warned this may not last forever. Carbon storage by land and sea has more than doubled in the past 50 years from about...
Even as man’s output of earth-warming CO2 has risen, so has the capacity of plants and the oceans to absorb it, scientists said, but warned this may not last forever.
Carbon storage by land and sea has more than doubled in the past 50 years from about 2.4 billion tonnes in 1960 to some five billion tonnes in 2010, said a study in Nature.
At the same time, fossil-fuel CO2 emissions rose almost fourfold.
“The growth rate of atmospheric CO2 continues to rise because fossil fuel emissions are accelerating not because sinks are diminishing,” researcher Ashley Ballantyne of the University of Colorado’s geology department said.
The finding was contrary to widespread expectations that carbon sinks were slowing their CO2 uptake.
“We were somewhat surprised by this result because several recent studies have been published showing that the land and oceans have been taking up less CO2,” said Ms Ballantyne.
“We discovered that the earth continues to take up more CO2 every year and there is no indication that this uptake has weakened.”
Ms Ballantyne and colleagues used reported annual changes in atmospheric CO2 levels, from which they subtracted annual total man-made emissions to quantify earth’s uptake.
About half of man-made CO2 emissions caused by burning fossil fuels and land-use changes, such as deforestation, are taken up by plants and the oceans.
CO2 can be stored away deep in the oceans for centuries.