By request: the precautionary principle

Reader MarkG asks

How much can we afford to allow the Global Warming Hypothesis (aka, the "scientific consensus") to cost us as a nation and society by applying the so-called Precautionary Principle?

I don't think he'll like my answer, but, quite a lot, really.  Cutting GDP by 5% would take us back to the dark days of 2004, which I personally don't remember as a squalid dystopian hell.  Running the air conditioner at a higher temperature, living in a smaller house, moving closer to work, and eating more frozen vegetables instead of fresh would be inconvenient, but none of these things would reduce us to misery.  People managed to live happy, fulfilling lives 50 years ago with a lot less stuff.  And the things that have produced the most dramatic improvements, like health care, wouldn't be much impacted.

How much economic growth to sacrifice to avert global warming is a thorny question for which I have no neat answer.  How do we weigh the interests of future generations against our own?  How should we deal with small but catastrophic risks?  Difficult.  All I can say is more than we're doing, and less than radical environmntalists would like us to.