There has been a recent debate on how much marginal agricultural land is available for biofuel production globally. A recent paper by Cai et al. (2011) claims that 320-720 million hectares of land is available. However, given high uncertainties in global datasets in general, this estimate needs to be rigorously evaluated and validated. Humanimpact.geo-wiki.org is specifically designed to help us assess the map produced by Cai et al. (2011).
Cai, X., Zhang, X. and Wang, D. (2011) Land availability for biofuel production. Environmental Science & Technology, 45(1), 334-339.
Competition has ended
Thank you very much for all your validations. The data you collect will be extremely valuable to help to better understand how much land is available for biofuel production.
The three winners have received their Amazon vouchers. You find a detailed validation quality/speed report here.
Note that the competition has now finished but validation will still be possible. We are planning to improve some of the aspects of humanimpact.geo-wiki.org such as sub-pixel categories.