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| Optimized land use could still significantly increase yields taking climatic conditions into account, keeping land use within limits. Photo Credit: Anita Bayer |
Double food production, save water and at the same time increase carbon storage - that sounds paradoxical, but would be theoretically possible, at least according to the biophysical potential of the earth. However, a radical spatial reorganization in land use would be necessary. Researchers from the Karlsruhe Institute of Technology (KIT) and the Heidelberg Institute for Geoinformation Technology (HeiGIT), an affiliated institute of Heidelberg University, found this out. They have their results in the Proceedings of the National Academy of Sciences.
How people use the surface of the earth, including for the production of food, has changed a lot in the past centuries. Today, more and more people live on earth, more food is needed and food can be transported around the world in a short time. However, as the study shows, the historically grown systems of food production do not reflect the biophysical potential of our ecosystems. Food is therefore not produced where there is area, water and CO2- would be the most efficient in terms of technology. Instead, according to the authors of the study, forests for arable and pasture land continue to be cleared and fields in arid areas irrigated - measures that have a massive negative impact on water availability and carbon storage.
But what would happen if fields, pastures and natural vegetation were instead moved to where it would be most efficient? If arable land were restricted to areas where intensive irrigation is not necessary? To find out, researchers from KIT and the Heidelberg Institute for Geoinformation Technology (HeiGIT), an affiliated institute of Heidelberg University, combined a dynamic vegetation model with an optimization algorithm, thus examining alternative arrangements of global land use and their effects.
On average over 80 percent more food and three percent more CO2- Storage by optimizing land use
The modeling of improved land use was carried out for climatic conditions from an optimistic and a currently more realistic climate change scenario for the near and distant future (2033 to 2042 and 2090 to 2099). The result: spatial restructuring alone could increase the production of food by an average of 83 percent, while at the same time the available amount of water by eight percent and the CO2-Storage would increase by three percent. The increases would be many times higher if one of the three targets were given priority over the other two.
"In our work, we only examine the biophysical potential as the basis for land use, which takes better account of the existing conflicting goals," says the study's first author, Dr. Anita Bayer from the Alpin Campus of KIT in Garmisch-Partenkirchen. "It turns out that there are regions in which certain land uses would clearly be advantageous, that is, 'optimal'. "According to the study results, tropical and boreal forests would have to be CO due to their outstanding function2-Storage is preserved in its natural state or reforested accordingly and is not used as an extension or pasture area. The temperate latitudes would mainly serve as arable land and to a small extent as pasture. This would compensate for the loss of space through the reforestation of tropical and boreal forests. The wide, open areas of the tropical and subtropical savannas and grasslands, in turn, would be used primarily as pasture and for animal feed production. "This picture of the optimal land use solutions has proven to be very stable in our work," added Bayer.
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Presentation of the optimal land use determined in the study. The green dots visualize possible optimal solutions with regard to food production, CO2-Storage and water availability, applied according to their global totals of the three target values. Behind each point is a map of the global distribution of natural areas, arable and pasture land. The red dot shows the suboptimal production of current land use. Illustration Credit: Bayer et. al, 2023
Make changes in land use conscious
The study shows that regional practice deviates greatly from the theoretically achievable optimum and that massive changes in land use would be necessary to better exploit the biophysical potential and thus increase the total yields of food, water and carbon storage together. "Even if such large-scale land use changes appear completely unrealistic at first glance, it is helpful to be aware that climate change will bring about major changes in the growing areas anyway," says Professor Sven Lautenbach, scientist at HeiGIT and the Geographical Institute of Heidelberg University. “These expected changes should not be allowed to happen, but should be tried more and more to shape them taking into account the biophysical potential.”
"Ensuring global food security is one of the main challenges of our time - and climate change will increase this problem in many regions," says Professor Almut Arneth from the Institute for Meteorology and Climate Research - Atmospheric Environmental Research, the KIT's Alpine campus in Garmisch-Partenkirchen. “Our study clearly shows that despite unfavorable climatic changes, there is potential to significantly increase agricultural yields through optimized land use and at the same time limit land use. It is now a matter of finding ways in which we can change our land use accordingly - taking into account the biophysical conditions, but also from a social point of view."
Published in journal: Proceedings of the National Academy of Sciences
Source/Credit: Karlsruhe Institute of Technology
Reference Number: en101123_01