When will we run out of land?

Between 1980 and 2000 over half of new agricultural land in the tropics was created through cutting down intact forest. Land clearing for crop production is a major issue for the maintenance of biodiversity and environmental stability but growing human demand for food is only one of several pressures on land, a resource that is rapidly shrinking.

Recently we at Agriculture for Impact came across a paper investigating global land scarcity, a topic much discussed in One Billion Hungry and on this blog. Published in 2011, the paper by Dr Lambin of Stanford University and Dr Meyfroidt of the University of Louvain, entitled Global land use change, economic globalization and the looming land scarcity, documents the processes that are driving global land use change and estimates when we might run out of land.

Of the total ice free land on the planet (13,300 million hectares), around 4,000Mha is suitable for rain-fed agriculture. The amount of land that is currently uncultivated, that isn’t forested, protected or populated by more than 25 people per km² is estimated at 445Mha and occurs mainly in the cerrados and grasslands of Latin America and the savannahs of Africa, which are important in themselves for biodiversity conservation and livestock grazing. The paper’s authors calculate low and high estimates of the amount of land needed to supply demand for different competing land uses:

Cropland for human food – an additional 2.7-4.9Mha each year depending on food waste, diets and efficiency.

Biofuels – 1.5-3.9Mha per year based on current biofuel mandates

Pasture – 0-5Mha per year based on the projected intensification of livestock systems

Urbanisation – 1.6-3.3Mha per year

Industrial forestry – 1.9-3.6Mha per year

Protected areas – 0.9-2.7Mha per year

Land degradation – 1-2.9Mha of land will be lost each year

Added together and balanced against current available land, and assuming that some deforestation will occur, means that current land reserves will run out by the late 2020s at the earliest and 2050 at the latest, and this is excluding the impacts of climate change.