Reducing Uncertainties in Soil Organic Carbon Predictions through “Management Learning”

November 8, 2017

Prof. Johannes Lehmann
Soil and Crop Sciences

Johannes Lehmann participated in a COP23 side event, Addressing Uncertainties in estimating GHG Emissions and removals in the AFOLU Sector to Strengthen Land Management Impacts, joining representatives of IRD, World Bank, CCAFS, and more.

More organic carbon resides in global soils than exists carbon in the atmosphere and the entire biosphere together. Therefore, small changes in soil organic carbon translate into meaningful changes in atmospheric carbon dioxide. This is the basis for the 4p1000 proposal: to increase existing soil organic carbon stocks by 0.4% each year and thereby match the remaining anthropogenic emissions. The proposal has generated excitement from various sectors, but also faces significant challenges. Scientists welcome the approach but also point out the huge task and the inadequate data to make informed decisions.

This presentation highlights some of the key misconceptions in the scientific and policy discussion and introduces an approach of iterative improvement of site-specific management. Such a “management learning” concept will rely on best management practices for a given soilscape and improve practices through organized data and continuously improved modeling. Critical is to recognize the difference between uncertainty in predicting the outcome of a management intervention and the variability of soil responses due to predictable differences in climate and soil type.

The vast majority of uncertainty does not lie in our inability to predict the outcome but in data management issues. Local data must be fed into models that will improve its performance for guiding management decisions locally and globally. This requires distributed data entry and its quality control, development of inexpensive sensors that are easy to use, and computational platforms that are fit for big data. Investments in sensor technology and operations can be financially justified through improved soil services as related to food, energy and water. The up-front investment in the science and infrastructure must be borne by the public sector, and will generate a vibrant industry around food-energy-water that contributes a vital pathway to global carbon dioxide removal.