Plants take in more CO2 - IPCC needs revisions

Lisa Welp-Smith of the Scripps Institution of Oceanography, California, and her team came up with a new method for measuring how much CO2 is absorbed and released by plants. The team used oxygen isotope markers in CO2 and more than 30 years of data from a global network that analyses air samples to measure changes in greenhouse gases, pollution and other factors.

"What this (finding) means is that plants are working faster than we thought they did," said Colin Allison, an atmospheric chemist and one of the study's authors, told Reuters from Australia. "Our analysis suggests that current estimates of global primary production are too low and the refinements we propose represent a new benchmark for models to simulate carbon cycling through plants, " Dr. Allison said.

The study was published on Thursday in the journal Nature.

Plants form a major part of the global carbon cycle in which carbon is continuously recycled and reused by plants and animals, the oceans and land. Carbon pollution from burning fossil fuels and burning forests adds to the CO2 in the air, disrupting the balance that keeps the planet warm. The team's finding suggests plants absorb 16 to 19 times mankind's total CO2 emissions, underscoring the powerful role they can play in regulating the climate.

Welp-Smith and Allison said it was too early to say how the new finding would affect climate change projections, in which supercomputer programs model how the climate will change.

"If we are right, and GPP needs to be revised upward by about 25 percent, it means that our fundamental understanding of how land plants function on the global scale is still a bit fluid," Welp-Smith told Reuters in an email, referring to gross primary production, a measure of photosynthesis.

But she cautioned that it doesn't mean more carbon is being locked away by plants. "It means more CO2 is passing through plants, not that it actually stays there very long."

Allison, of Australia's Commonwealth Scientific and Industrial Research Organization in Melbourne, said the study gives a better estimate of what's really happening in the atmosphere.

The team made the finding by tracing the path of oxygen atoms in CO2 molecules, and Dr. Allison said the current global gross primary production estimates of 120 billion tonnes of carbon a year should be revised to between 150 and 175 billion tonnes of carbon a year.

Looks like the IPCC needs to do some revisions.

See also The Earth is happily gobbling more CO2.