Malthus with a computer


Predictions Revisited

Malthus with a Computer”

Take a model that purports to predict the future and just run it back to the past. The result are sometimes salutary. Ross McKitrick of Guelph (celebrated for his role in trashing the warmist’s Hockey Stick) has done that with a model from the Canadian Medical Association.

The model predicts a shocking loss of life from air pollution. As reported last week by Peter Shawn Taylor in Canada’s Financial Post, McKitrick put 1960s levels of air pollution into the model and found that the deaths it attributed to pollution in the Toronto area reached more than 100% of all the people who actually died. As McKitrick said, “It just doesn’t make sense.”

The story rang a bell with me, about a famous computer model of the early 1970s, which spawned the best-seller The Limits to Growth from Donella H. Meadows and her colleagues at MIT. It predicted industrial pollution growing out of control and a global population crash in the 21st Century. That may sound familiar, but four decades ago the pollution wasn’t greenhouse gases but good old-fashioned smog and poisonous wastes from industry and agriculture.

Here is the “standard” projection in The Limits to Growth 1972. It runs from 1900 to 2100. You can see the global population climbing and outstripping food production, so that food per capita falls, bringing the population down with it. Meanwhile natural resources, starting high in 1900, are being rapidly exhausted at the end of the century, and converted into steadily rising industrial output and accelerating pollution. Everything unravels in the early 21st Century, with agriculture and industry collapsing, and billions of people dying.

As I noted in my book 1984 and After, Sam Cole and Ray Curnow of SPRU (the Science Policy Research Unit at Sussex University) ran the Limits to Growth model backwards. It told them that, before 1880, the world’s population was infinite. Again: “It just doesn’t make sense.”

A book of essays rebutting The Limits to Growth, produced by SPRU (see the Cole reference),  pointed out that a moderate rate of discovery of new resources, combined with slow progress in pollution control, would completely avoid the predicted disasters. Chris Freeman, SPRU’s director, called his own critique ‘Malthus with a computer’.

There’s a sub-plot in this story, about the Club of Rome that funded the original Limits to Growth study. Aurelio Peccei, an Italian industrialist, and Alexander King, a British scientific civil servant, founded it in 1968. King tried hard to seduce me with the idea that international technocrats should rule the world. I’m sorry to say I can see some influence on my writings in the late 1960s. But Limits to Growth brought me to my senses. What if the technocrats’ expectations are completely wrong?

Nowadays the Club of Rome is seen by some as the spider that spun the web of authoritarian environmentalism, which then promoted the global warming scare two decades later. I leave that as a googling exercise for the readers to pursue if they wish. Better to end, perhaps, with a limerick that I learnt from Chris Freeman of SPRU.

A trend is a trend is a trend

But when and how does it bend?

Does it rise to the sky,

Or lie down and die,

Or asymptote on to the end?


Shawn Taylor’s article in the Financial Post is here:

Donella H. Meadows, Dennis L Meadows, Jørgen Randers and William W. Behrens, The Limits to Growth, New American Library, 1972

Nigel Calder, 1984 and After, Century Publishing, 1983.

H.S.D. Cole, Christopher Freeman, Marie Jahoda and K.L.R. Pavitt, Thinking About the Future: a Critique of the Limits to Growth, Chatto & Windus for Sussex University Press, 1973