The classic apocalypse has four horsemen, and our modern version follows that pattern, with the four riders being chemicals (DDT, CFCs, acid rain), diseases (bird flu, swine flu, SARS, AIDS, Ebola, mad cow disease), people (population, famine), and resources (oil, metals)
From over population, to pandemics, peak oil to climate change, Ridley provides examples of human innovation that have averted the disasters, real or imagined. He does not declare the doomsayers to be wrong, merely hyperbolic in their predictions.
we hear a lot from those who think disaster is inexorable if not inevitable, and a lot from those who think it is all a hoax. We hardly ever allow the moderate “lukewarmers”
Given the current discussions on rich vs poor, conservative vs liberal, religious versus non-religious, maybe a little moderation should be in order. After all, there are a lot of examples of "experts" who got it completely wrong in the past.