Warming soils releasing carbon ?  

The Washington Post has a depressing report on a new paper on nature on clime system feedback, with warming soils releasing carbon themselves - Scientists have long feared this ‘feedback’ to the climate system. Now they say it’s happening.

At a time when a huge pulse of uncertainty has been injected into the global project to stop the planet’s warming, scientists have just raised the stakes even further.

In a massive new study published Wednesday in the influential journal Nature, no less than 50 authors from around the world document a so-called climate system “feedback” that, they say, could make global warming considerably worse over the coming decades.

That feedback 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). 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.

It’s this concern that the new study validates. “Our analysis provides empirical support for the long-held concern that rising temperatures stimulate the loss of soil C to the atmosphere, driving a positive land C–climate feedback that could accelerate planetary warming over the twenty-first century,” the paper reports. 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.