Peak Farmland: The End of Agricultural Expansion?

We’ve heard of the imminent peak oil, peak water, and in some circles even peak soil. Now researchers at the Rockefeller University in New York say that we may have reached peak farmland. This is not to say that the planet no longer has arable land to spare, but rather that agricultural production has reached a point at which no new land is needed to grow adequate food. A recent study by Ausubel, Wernick, and Waggoner cites increased yield per hectare in countries like India and China as reining in agricultural land expansion.

India’s experience with Green Revolution technologies that enhanced productivity is used to exemplify the potential to spare land from cultivation, despite the increase in consumption that accompanies growing population and incomes. The analysis, however, broadens to a global perspective of cropland using a model based on population, affluence, consumption, and technology (ImPACT). According to the authors, curbing some of the main factors on increased demand for food – continued population growth, changes in diet associated with affluence, biofuels – could reverse the trajectory of land use.

Reducing the amount of land needed for agriculture in theory increases the amount of land housing high levels of biodiversity and providing ecosystem services like clean water and greenhouse gas sequestration. But is this true in practice? The study demonstrated a correlation between increased productivity and stable or reduced land under cultivation, but barely addressed the environmental impacts of intensification. After acknowledging that widespread irrigation and fertilizer use helped fuel the historical improvement in crop yields, the study fails to discuss the consequences of input-intensive or large-scale simplified systems on water quality, land degradation, or greenhouse gas emissions. Furthermore, the research neglects to factor into its projections the impacts that climate change will have on yield and viable land for cultivation. The health of land in production and its ability to provide critical ecosystem services affect “spared” natural or restored areas, and so it is critical to consider these different land uses from a landscape perspective. Of course, there is also the question of what actually happens to the land taken out of cultivation – whether it is restored to forest or grassland habitat, or goes to serve some other purpose.

These research findings demonstrate the potential for taking land out of cultivation for the benefit of nature, but that also brings us back to a core debate in integrated landscape approaches, that of ‘land sparing vs. land sharing.’ While it is important to consider how better agriculture practices can limit expansion of farmland, that does not mean agriculture land is devoid of value in preserving biodiversity and ecosystem services. What works best ultimately depends on the objectives within a landscape and the specific social and biophysical contexts.

Do you have thoughts on either the notion of reaching ‘Peak Farmland’ or the debate between land sparing vs. sharing? Leave a comment below!

For more, read the full article, Peak Farmland and the Prospect for Land Sparing, online. Also visit the New York Times and the Food and Climate Research Network for commentary (and some very enlightening reader comments).