|Predicted changes in soil carbon |
per pixel by 2050 under the
‘no acclimatization’ scenario
The "feedback" researchers are referring to "involves the planet’s soils, which are a massive repository of carbon due to the plants and roots that have grown and died in them, in many cases over vast time periods (plants pull in carbon from the air through photosynthesis and use it to fuel their growth)," Chris Mooney reports for The Washington Post. "It has long been feared that as warming increases, the microorganisms living in these soils would respond by very naturally upping their rate of respiration, a process that in turn releases carbon dioxide or methane, leading greenhouse gases." Researchers said that is happening.
"Our analysis provides empirical support for the long-held concern that rising temperatures stimulate the loss of soil C [carbon] to the atmosphere, driving a positive land C-climate feedback that could accelerate planetary warming over the 21st century." Mooney notes,"This, in turn, may mean that even humans’ best efforts to cut their emissions could fall short, simply because there’s another source of emissions all around us. The very Earth itself."
Jonathan Sanderman, a climate scientist with the Woods Hole Research Center in Massachusetts, said the study gives “strong support to the hypothesis that soils will release a substantial amount of carbon in response to rising air temperatures," Mooney writes. Sanderman told Mooney, "This is really critical, because if the additional release of carbon is not counterbalanced by new uptake of carbon by plants, then it’s going to exacerbate climate change and increases the urgency to immediately reduce greenhouse gas emissions.”
But Sanderman "also noted studies have suggested that better management of agricultural soils could sequester large amounts of carbon, perhaps enough to offset the losses projected in the study."