Berkeley Lab: Soil Carbon Release Could Be Far Larger Than Thought: 30% Of Today's Anth. Output

[hatrack]

The results shed light on what is potentially a big source of uncertainty in climate projections. Soil organic carbon harbors three times as much carbon as Earth’s atmosphere. In addition, warming is expected to increase the rate at which microbes break down soil organic carbon, releasing more CO2 into the atmosphere and contributing to climate change.

But, until now, the majority of field-based soil warming experiments only focused on the top five to 20 centimeters of soil—which leaves a lot of carbon unaccounted for. Experts estimate soils below 20 centimeters in depth contain more than 50 percent of the planet’s stock of soil organic carbon. The big questions have been: to what extent do the deeper soil layers respond to warming? And what does this mean for the release of CO2 into the atmosphere? “We found the response is quite significant,” says Caitlin Hicks Pries, a postdoctoral researcher in Berkeley Lab’s Climate and Ecosystem Sciences Division. She conducted the research with co-corresponding author Margaret Torn, and Christina Castahna and Rachel Porras, who are also Berkeley Lab scientists.

“If our findings are applied to soils around the globe that are similar to what we studied, meaning soils that are not frozen or saturated, our calculations suggest that by 2100 the warming of deeper soil layers could cause a release of carbon to the atmosphere at a rate that is significantly higher than today, perhaps even as high as 30 percent of today’s human-caused annual carbon emissions depending on the assumptions on which the estimate is based,” adds Hicks Pries.

The need to better understand the response of all soil depths to warming is underscored by projections that, over the next century, deeper soils will warm at roughly the same rate as surface soils and the air. In addition, Intergovernmental Panel on Climate Change simulations of global average soil temperature, using a “business-as-usual” scenario in which carbon emissions rise in the decades ahead, predict that soil will warm 4° Celsius by 2100.

EDIT

http://newscenter.lbl.gov/2017/03/09/soils-carbon-climate/

[Jarqui]

1. At the bottom of the article:

DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time.

I doubt they'll be able to say that much longer with Trump.

To quote Trump, "sad".