Many of the gloomy predictions of Earth Day in 1970 didn't happen because we heeded the warnings (National View: "On Earth Day, celebrate how gloomy predictions didn't come to pass," April 22).
The marketplace played a role, but it was a marketplace shaped by government regulation to provide incentives for acting in the public interest. Automobiles to houses are more efficient today despite oil that is cheaper than it was in 1970 when 15 mpg was great mileage. That happened because of government intervention at the urging of the public.
Earth Day in 1970 was a public demand for action that was heeded. Let's hope we have the same demands heeded 50 years later. Then ideologues 50 years from now can talk about how those "doom and gloom" predictions of global warming turned out to be exaggerated.