Extent of Global Agriculture
Urban populations grow detached from their remote impact on the environment
Agriculture provides food, fibre and other products that sustain human life. It is one of the most pervasive drivers of environmental change on Earth through its direct and indirect impacts on climate, biodiversity, land degradation and freshwater. Its extent reflects the growth and migration of the human population to every part of the planet.
In 1700, over 2.65 million km2 of land were devoted to cropland worldwide; in 2014, the total area of croplands was estimated to be 20.39 million km2, which represents an eight-fold expansion.
Croplands occupy about 14 % of the total ice-free land area on the planet, while pastures occupy about 26 %. Nearly half of the world’s agricultural land (44 %) is located in drylands, mainly in Africa and Asia, and supplies about 60 % of the world’s food production. Most of this production has been achieved through the Green Revolution – improved seeds, chemical fertilisers, enhanced technologies and irrigation. Food production in drylands is threatened by water shortages, climate change, land degradation and persistent poverty. Climate change may have a major impact on drylands as temperatures become more extreme (hot and cold), rainfall declines, groundwater tables drop and climate zones shift. Although climate change will likely increase aridity, the actual risk to agriculture is difficult to quantify. In addition, economic uncertainties and social unrest can lead to “debilitating levels of outmigration and instability” in drylands, which, besides the direct toll on human presence, may lead to lower agricultural productivity and further stagnation and marginalisation of local economies.
Agricultural production must continue to meet the needs of a rapidly growing global population. One estimate is that over 1 billion hectares of "wild" land will have to convert to agriculture to feed the global population by 205010. However, not all land is suitable for agriculture and there is intense and increasing competition for land due to urbanisation, bioenergy farming, forest plantations and protected areas.
An alternative is found in ‘sustainable intensification’, which includes ceasing agricultural expansion, closing ‘yield gaps’ (the difference between observed yields versus maximum potential yields) on underperforming lands, increasing efficiencies (management, technologies), reducing overuse of water and fertilisers, shifting diets from meat to plants, and reducing waste. Regardless of the pathways taken, maintaining dryland production will be a challenge in the future
Agriculture and land degradation
Increased agricultural production is essential to feed a growing population. However, the expansion of agriculture into “new” lands often threatens local and regional ecosystems. Intensification of production on existing agricultural lands to fill “yield gaps” is also a threat to the environment through the potential overuse of water, fertilisers and pesticides that affect local and regional water resources and ecosystems. The drylands will play a major role both in providing lands for “new” agricultural production and opportunities to intensify existing production. Charting an “optimum” path among these options that meets desired needs and minimises environmental damage is the challenge of this century.
Source: C. Martius
Distribution of global population in Urban Centres, Urban Clusters and rural settlements in 2015. About 85 % of global inhabitants live in cities, in Urban Clusters and Urban Centres.
Source: P. Martino et al.