A paper from an international team of researchers just came out, estimating that urban ag composes 11% of all irrigated cropland and 4.7% of all rainfed cropland.
While you can’t just add these two numbers to get a total extent of urban ag*, it seems nevertheless striking that such a very approximate total would give 15.7% of cropland–very close to the USDA’s uncited estimate of 15% that appeared on their urban agriculture homepage, at least, it did between Feb. 2012 and March 2013. For some reason, after the latter date, the page was updated to include no estimate whatsoever. Given that it appeared to be a “guestimate”, perhaps that’s understandable. But given this recent paper, it seems (a) that estimate, or the more precise one given by Thebo et al. by breaking out rainfed and irrigated separately, should return to the website, and (b) the idea that urban/peri-urban agriculture will not/does not significantly contribute to food security should be banished to the dustbins of history. (At least until a contrary study appears?)
And I can’t help but note that this does give grist to my previous comment: as important as I think organic/agroecological agriculture is, this latest evidence does indeed imply that “urban food production may be many times larger than the organic sector“–and so it should garner our sustained and increasing attention, I’d say.
* “…their sum does not necessarily represent the total urban cropland area when the maximum extent of irrigated and rainfed croplands occurs in different months.”