The market was supposed to save the planet.
That, at least, was the argument of many economists grappling with the problem of climate change. As fossil fuels became scarcer, they pointed out, the price of oil and natural gas would go up. And then other options, like solar and wind, would become cheaper, particularly as investment flowed into that sector and drove down the cost of new technologies.
And voila: The invisible hand would gradually turn down the global thermostat.