"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.
According to the study of the 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.
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The paper therefore found that the biggest losses were in Arctic regions, where soils are warming rapidly and also where they are quite thick — but also that well down through the mid-latitudes, soils were also losing carbon. And the net result for the research plots as a whole was a loss of soil carbon.
The paper then extrapolated these findings for the globe, finding that by the year 2050, the planet could see 55 billion tons of carbon (which converts to 200 billion tons of carbon dioxide, were it all to be released in this form) released from soils. That’s if we continue on with a “business as usual” scenario of global greenhouse gas emissions and accompanying warming."
