Areas available for agriculture: a new perspective
The results of the study[1] presented by three German researchers at the 27th European Biomass Conference in Lisbon last May, deserve wide dissemination. They shed new light on the area that can be exploited for agriculture in each region under environmentally sustainable conditions, that is, by preserving forests and habitats of high ecological value, as well as "areas under natural constraints" unsuitable for cultivation or livestock farming due to climate or topology.
The authors of the study, who work at Bauhaus Luftfahrt e. V.[2], near Munich, used high-resolution geospatial data – up to 15 arc seconds[3] – to estimate the areas allocated to different types of land use (inland waters, forests, populated or artificial areas), as well as to protected habitats and areas “too cold, too dry or too steep” for rain-fed agriculture. The difference, in each region, between the total land area and the areas occupied by these different categories, taking into account double counting, corresponds to the area available for environmentally sustainable agricultural activity. Overall, 3,729 million ha or 27 billion hectares of the planet’s surface can be used for this purpose. The regions with the majority of areas available for agriculture, taking into account ecological constraints, are sub-Saharan Africa (21 billion hectares of the total), East Asia (15 billion hectares), the former USSR (12 billion hectares) and North America (11 billion hectares) (table).
The information provided by the satellites is, according to the authors, "of unprecedented depth and quality." The contrast they offer with the statistics of the Food and Agriculture Organization of the United Nations, which are generally used as a reference, is all the more striking. According to the FAO, 4,886 million hectares were used for crops and livestock in 2013, a figure significantly higher than the area that German researchers consider available for environmentally friendly agriculture. The discrepancy between the two figures stems mainly from the fact that a large proportion of areas under natural constraints—and, to a lesser extent, a portion of protected habitats—are used as livestock pastures.[4]. Such a gap is observed in all regions; for example, in sub-Saharan Africa, the FAO estimates the agricultural area at 958 million ha, while the study estimates the available area at 797 million ha. On the other hand, the FAO and study data are very close in all regions with regard to the extent of forest cover.
The Bauhaus Luftfahrt study has significant implications for agricultural policy. If ecological constraints are taken seriously, the potential of land still untapped for agriculture appears, in almost all regions, to be zero or at least very low. While irrigation projects can be built in areas with natural constraints to overcome drought, these developments come at significant costs and pose environmental risks, such as soil salinization and the depletion of groundwater. The increase in agricultural production required to feed the expanding world population will therefore have to come primarily from sustainable intensification, in other words, from increased yields made possible by practices that respect soil fertility and the health of humans, plants, and animals.
[1] Florian Riegel, Arne Roth and Valentin Batteiger, “Global assessment of sustainable land availability for bioenergy and food production”, 27th European Biomass Conference and Exhibition, 27-30 May 2019, Lisbon.
[2] Bauhaus Luftfahrt is, according to its website, "a multidisciplinary think tank" supported by four aerospace companies, including Airbus, as well as the Bavarian Ministry of Economic Affairs, Media, Energy and Technology. It employs around fifty people, who work on the issue of transport, particularly air transport, "using a holistic approach that combines technical, economic, social, and ecological aspects."
[3] According to Wikipedia, one arcsecond is approximately the apparent size of a basketball 50 km away.
[4] For example, according to the authors of the study, the FAO estimates the agricultural area in Saudi Arabia at 173 million ha (mainly comprising desert areas used as pastures by nomads), while the study estimates the area available for agriculture as zero, "due to severe humidity constraints."
