My view of environmentalists is that they use the fixed-coefficients production function for long-term forecasting. Thus, they ignore substitution and technological change. Ronald Bailey reviews the many mistaken predictions based on this methodology. For example,

For the first Earth Day in 1970, Ehrlich, in an article entitled “Eco-Catastrophe” in The Progressive magazine, offered a scenario in which four billion people would starve to death between 1980 and 1989, 65 million of whom would be Americans.

Bailey concludes,

as biologists and ecologists, they tend to think that human beings are merely more clever herds of deer. When deer run out of their sustenance, they die. When human beings begin to run out, they turn their brains and their social institutions to producing more.

For Discussion. Which pessimistic environmentalist predictions have come the closest to being fulfilled?