Improving soil quality can slow global warming. Better land management practices can sequester enough carbon to lower global temperatures
Low-tech ways of improving soil quality on farms and rangelands worldwide could pull significant amounts of carbon out of the atmosphere and slow the pace of climate change, according to a new University of California, Berkeley, study.
The researchers found that well-established agricultural management practices such as planting cover crops, optimizing grazing and sowing legumes on rangelands, if instituted globally, could capture enough carbon from the atmosphere and store it in the soil to make a significant contribution to international global warming targets.
Their initial aim was to determine if such practices could reduce global temperatures at least 0.1 degree Celsius (0.18 degrees Fahrenheit). This is one-tenth of the Intergovernmental Panel on Climate Change's goal of limiting the average global temperature increase between now and the year 2100 to 1 degree Celsius (1.8ºF), or 2" degrees Celsius (3.6ºF)" above temperatures before the industrial revolution.
When combined with aggressive carbon emission reductions - the best scenario for limiting warming from climate change - the study found that improved agricultural management could reduce global temperatures 0.26 degrees Celsius - nearly half a degree Fahrenheit - by 2100.
The researchers did not consider newer practices, such as composting, that are not studied as widely, nor did they consider the effect of improving soil on abandoned land, both of which could increase soil carbon sequestration even more. Newer climate models also could simulate how carbon uptake will change as temperatures rise and rainfall patterns change.
"The point of our paper was to look at the temperature effect of implementing existing low-tech technologies already practiced within agriculture, in developing as well as developed countries," Mayer said. "There could theoretically be an immediate and widespread adoption of many of these practices."
With aggressive emissions targets, improved land management could pull about 1.78 petagrams of carbon from the atmosphere each year, while adding biochar to the mix could raise the yearly sequestration rate to 2.89 petagrams.
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- Allegra Mayer, Zeke Hausfather, Andrew D. Jones, Whendee L. Silver. The potential of agricultural land management to contribute to lower global surface temperatures. Science Advances, 2018; 4 (8): eaaq0932 DOI: 10.1126/sciadv.aaq0932