(1) http://www.wfp.org/1billion
(2) http://www.census.gov/ipc/www/idb/worldpopgraph.php
(3) http://earthtrends.wri.org/features/view_feature.php?fid=7&theme=6
(4) http://www.fao.org/news/story/en/item/20351/icode/
(5) Erik Millstone and Tim Lang (2003). “The Atlas of Food”. Earthscan UK (p34)
Calculation:
34% x 2,287 million tonnes of grain produced = 777 million tonnes produced to feed livestock, divided by 180kg (amount needed to feed a person) = 4.3 billion people
