Half the land now needed to grow food crops could be spared if attainable crop yields are achieved globally.
A new IIASA study shows that about half the land currently needed to grow food crops could be spared if attainable crop yields were achieved globally and crops were grown where they are most productive.
The study results indicate that with high nutrient inputs and reallocation of crops on present cropland, only about half the present cropland would be required to produce the same amounts of major crops. The other half could then in principle be used to restore natural habitats or other landscape elements.
The findings also show that land use is currently somewhat inefficient and not primarily due to the upper limits to crop yields as determined by climate in many parts of the world, rather, it is strongly subject to management decisions.
According to the authors of the study published in Nature Sustainability, the need for this type of strategy is urgent, given the increasing global demand for agricultural products. The study is the first to provide insight into the amount of cropland that would be required to fulfill present crop demands at high land use efficiency without exacerbating major agricultural impacts globally.
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The researchers say that it is difficult to say exactly how much biodiversity is impacted as a direct result of agricultural activities, but it is estimated to exceed safe boundaries, primarily due to habitat loss. In this regard, they evaluated two scenarios: the first proposes maximum land sparing without constraints, except for the present cropland extent, while the second scenario puts forward targeted land sparing that abandons cropland in biodiversity hotspots and uniformly releases 20% of cropland globally.
There were only marginal differences between the two scenarios in most aspects, except for wildlife habitat, which only increased significantly with targeted land sparing. This however still enabled reducing the cropland requirement by almost 40%.
Furthermore, the researchers found that greenhouse gas emissions and irrigation water requirements are likely to decrease with a reduced area of cultivated land, while global fertiliser input requirements would remain unchanged.
Spared cropland could also provide space for substantial carbon sequestration in restored natural vegetation. Yet, potentially adverse local impacts of intensive farming and land sparing such as nutrient pollution or loss of income in rural areas will need to be studied further.