Saving the climate from the ground up Research team with participation of the University of Bonn formulates strategy against the greenhouse effect
Soil has the capacity to bind large quantities of carbon in the long term. An international team of researchers, including from the University of Bonn, is now advocating effective use of this potential. Experts estimate that this could reduce the increase of the greenhouse gas carbon dioxide in the atmosphere by a third. At the same time, agricultural yields in many regions would also increase significantly. In a recent publication they present a strategy to achieve these goals. The study is published in the journal Nature Communications.
Increased carbon inputs into the soil could slow down climate change and at the same time increase crop yields, the international research team emphasizes. (© Frank Luerweg / University of Bonn)
The climate summit in Paris in 2015 was also the birth of the so-called "4 per 1,000" initiative. Its name stands for a link that has not received enough attention in climate research and politics for a long time: Every year the amount of carbon in the atmosphere increases by more than four billion tons due to the man-made greenhouse gas CO2. If these four billion tons were instead sequestered in the earth's soils (thus completely halting the greenhouse effect), the amount of carbon contained in the soil would grow by only 0.4 per cent annually (i.e. four out of 1,000). In other words: Soils are already a gigantic carbon store. So why not simply dump the excess CO2 in it as an additional minuscule amount?
Experts are indeed confident today that this strategy could significantly slow down climate change. "0.4 percent additional carbon input is somewhat too optimistic," explains Prof. Wulf Amelung, who heads the Division of Soil Science at the University of Bonn. "However, a third of this is probably achievable." Nevertheless, little has changed since 2015. Together with colleagues from Europe, the USA, Australia and China, Amelung and colleagues therefore want to put the issue back on the agenda. In the current issue of the journal "Nature Communications", they outline a strategy to effectively use the potential of soils in the fight against climate change. Amelung, together with his French colleague Prof. Abad Chabbi, is in charge of the initiative; in Germany, the TU Munich and Forschungszentrum Jülich were also involved.
There are a number of simple measures to increase the amount of carbon in the soil, such as mulching (i.e. covering the soil with crop residues) or adding plant-based coal. The most important method, however, is to increase plant growth (and thus crop yields): by liming acidic soils, by fertilizing as needed, by using smart irrigation. "The more grows on the soil, the better is it rooted," explains Amelung. "And roots with their widely branching networks of organic material store lots of carbon." Conversely, the organic matter contains essential nutrients for plant growth and thus promotes crop yield. "Our strategy therefore ultimately addresses two important goals: climate protection and food security." [...]
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