Next time you meet a Transition Towner who wants to tell you that everyone should localise food production, ask him / her about what happens to the following countries:
Singapore, Djibouti, Bahrain, Kuwait, Guam, Brunei, US Virgin Islands, French Polynesia, Seychelles, Northern Mariana Islands, Andorra, Maldives, Bermuda, Puerto Rico, Qatar, UAE, St Lucia, Cayman Islands, Trinidad and Tobago, Aruba, Grenada, Malta, Kiribati, Oman, Iceland, Micronesia, Bahamas, Jordan, West Bank & Gaza, American Samoa, Solomon Islands, San Marino, Korea (Rep. of), Japan, Marshall Islands, Lebanon, New Caledonia, Mayotte, Egypt, Papua New Guinea, Netherlands Antilles, Israel, Costa Rica, Colombia, Sri Lanka, Palau
…all of which have 0.0 hectares of arable land per person, when rounded to one decimal place, according to World Bank data. (In fairness, any self-respecting Transitioner will probably argue back that with the latest permaculture techniques, they can feed a family of four on a parcel of land the size of a postage stamp – although see this post for some questions about those claims.)
More data from the same source: in 1960, the world had 0.39 hectares of arable land per capita. In 2007, the figure was 0.21 hectares – this even after the effects of massive deforestation to bring more cropland into production. Only four countries have more than 1 hectare of arable land per person: Niger (1.0), Canada (1.4), Kazakhstan (1.5) and Australia (2.1).