The Population Bomb

Paul Ehrlich famously predicted famines at the end of the last century, in which hundreds of millions of people would starve to death.

Forty years later, no such mass starvation has come to pass. While there have been tragic famines resulting in millions of deaths since 1968, none occurred because global food production failed to keep pace with population growth the core of Ehrlich’s hypothesis. Per capita global food production has, instead, increased by 26.5 percent between 1968 and 2005, according to the World Resources Institute. The number of people who starve to death daily declined from 41,000 in 1977 to 24,000 today, according to The Hunger Project, an organization combating global hunger.

One bit caught my attention...

Ehrlich also fretted in "The Population Bomb" that we were depleting the world oxygen supply by paving terrestrial areas, burning fossil fuels and clearing tropical forests. Green party campaigner Peter Tatchell recently reasserted this claim in the U.K. newspaper, The Guardian. “Compared to prehistoric times, the level of oxygen in the earth’s atmosphere has declined by over a third and in polluted cities the decline may be more than 50 percent,” Tatchell wrote.
But as physicist Luboš Motl points out in his blog, the oxygen scare is nonsense. Atmospheric oxygen has been at 20.94 percent or 20.95 percent for thousands of years, amounting to about 150,000 tons of oxygen per capita. Motl estimates that, at most, any atmospheric oxygen drop due to the combustion of fossil fuels might — at most — be 0.02 percent, a loss that could easily be offset by natural oxygen-producing processes.

That oxygen decline is an interesting claim. If the level of oxygen in the atmosphere has actually declined by as much as is claimed due to pollution, someone should have noticed by now. If we take the current level of 20.95% as two-thirds of some prehistoric standard, then a drop in cities to one half of that would mean the oxygen levels are as low as 16%.

According to OSHA,

"Hazardous atmosphere" means an atmosphere that may expose employees to the risk of death, incapacitation, impairment of ability to self-rescue (that is, escape unaided from a permit space), injury, or acute illness from one or more of the following causes:
....
(3) Atmospheric oxygen concentration below 19.5 percent or above 23.5 percent;

This would make it illegal to work in cities. Don't you think someone would have said something by now?