sions over 30 years (Searchinger et al., 2008). Biofuels from Already, drastically raised food prices have resulted in violent
switchgrass, if grown on US corn lands, will increase emis- demonstrations and protests around the world in early 2008.
sions by 50% (Fargione et al., 2008). It is evident that the main Current OECD scenarios by the IMAGE model project a mean
potential of biofuels lies in using waste biomass or biomass increase in the proportion of land allocated to crops for biofuel
grown on degraded and abandoned agricultural lands planted production equivalent to 0.5% of the cropland area in 2008,
with perennials (World Bank, 2007; FAO, 2008). 2% by 2030 (range 1–3%) and 5% by 2050 (range 2–8%).
Production of crops for biofuels also competes with food pro- Production of other non-food crops is also projected to increase.
duction (Banse et al., 2008). Indeed, the corn equivalent of the For example, cotton is projected to increase to an additional 2%
energy used on a few minutes drive could feed a person for a of cropland area by 2030 and 3% by 2050 (Ethridge et al., 2006;
day, while a full tank of ethanol in a large 4-wheel drive subur- FAPRI 2008). Hence, the combined increase in cropland area
ban utility vehicle could almost feed one person for a year. A designated for the production of biofuels and cotton alone
recent OECD-FAO (2007) report expected food prices to rise could be in the range of 5–13% by 2050 and have the potential
by between 20% and 50% by 2016 partly as a result of biofuels. to negatively impact food production and biodiversity.
LOSS OF CROPLAND FROM URBAN DEVELOPMENT
with 5 of the 7 estimates below 0.5%. Most of the differences
can be explained by the various definitions of built-up area and
differences between satellite derived and inventory based data.
All these percentages relate to about 0.3–3.5 million km
2
of
land worldwide, which at first appear to be unavailable for pro-
ducing food. However, UNDP (1996) estimated that 15– 20%
of the world’s food is produced in (peri-)urban areas (although
it is not clear whether parts of this peri-urban area are already
included in cropland inventories or not; besides there is large
uncertainty and variability by city/region of the UNDP esti-
mate).
Preliminary future estimates based on the HYDE methodol-
ogy (Beusen and Klein Goldewijk, in prep) with the medium
population growth variant of the UN (2008) reveal that with
an expected increase of the global urban population from 2.9
billion people in 2000 to 5 billion in 2030 and 6.4 billion in
2050, the built-up area is likely to increase from 0.4% of the
Infrastructure and urban development is increasing rapidly total global land area in 2000 to about 0.7% by 2030, and to
(UN, 2008). Settlement primarily occurred at the cost of crop- 0.9% by 2050, corresponding roughly to 0.5 million km
2
, 0.9
land, as people historically settled in the most productive loca- million km
2
and 1.2 million km
2
, respectively.
tions (e.g., Maizel et al. 1998; Goldewijk, 2001, 2005; Klein
Goldewijk and Beusen, 2009). Hence, as settlements, towns The computed ratio of built-up area/cropland area is 3.5% in
and cities grow, the adjacent cropland is reduced to accommo- 2000, 5.1% in 2030 and 7% in 2050, respectively. This means
date urban infrastructure such as roads and housing. Globally, that if all additional built-up area would be at the expense of crop-
estimates of the extent of built-up areas in 2000 range from land (Stehfest et al., 2008), a total of 0.37 million km
2
of cropland
0.2% – 2.7% of the total land area (Potere and Schneider, 2007) would be lost by 2030, and another 0.30 million km
2
by 2050.
3
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