The Limits to Protein

The Limits to Protein

The Limits to Protein

by David Butcher


David Butcher (Australian, born 1941) is a veterinarian with particular interests in epidemiology, wildlife diseases, and biodiversity conservation. He is a former CEO of WWF Australia and Greening Australia (NSW) and now lives on an Illawarra property that is 30% subtropical rain forest.

Scarcity of high-quality animal protein—partly from land-based animals and partly from fish and other products from salt or freshwater—will confront us over the next forty years.

Total world protein production will likely remain similar to present-day levels. The catch of marine fish has already stagnated and may decline dramatically toward 2052. But the decline will be compensated for through aquaculture production, as long as there is enough feed. The availability of feed, too, will determine supplies of land-based protein such as beef, chicken, and pork.

The production of plants for feed is highly susceptible to unexpected variations in the weather. Land-use change, degradation from poor management practices, desertification, and inundation from sea-level rise will all add pressure to the world’s arable land. Improved irrigation practices will help, but water availability will remain critical, especially in international river basins where tensions and outright conflict will erupt over it.

On the positive side, science will provide some relief through the development of improved plant strains, more efficient irrigation techniques, effective fertilizer use, and efficient pyrolysis of vegetation in order to increase soil carbon. Improved genetics and animal husbandry will produce more productive flocks and herds.

But feeding the animals used for human protein consumption will be in direct competition with human needs for grain crops and also for animal protein. Ruminants will continue to use nonarable lands transforming low-quality herbage into high-quality protein. But the production of pork will decline because pigs compete directly for human-grade carbohydrates and protein. Poultry products will become the mainstay because these birds convert feed into protein with high efficiency. Furthermore, poultry populations can be rapidly expanded and contracted to take advantage of fluctuations in feed availability.

Aquaculture is widely seen as the natural supplement to the stagnating catch of wild fish. But aquaculture requires a steady flow of high-quality—usually fish—protein to feed the captive fish. A number of freshwater species have great promise because of their lower protein requirements, but they are usually less popular in the marketplace. So aquaculture will remain a competitor for protein-rich feed by 2052.

The distributional effect of the limited supply of protein will be ugly. The affluent will force up prices and consume what high-quality protein there is. The poor, especially in urban areas, will get less, and signs of protein deficiency will reappear, with resultant disease and a lowering of the quality of life for those affected.