August 29, 2004 · Richard Posner
Interesting comments, as usual; and since this is my last day as Larry’s guest blogger, I think I’ll limit myself to responding to comments. (Unfortunately, I can’t respond to all–and of course some comments are responded to very well by other commenters. I am impressed by the quality and interactive character of many of the comments.)
One commenter corrected my statement that the Copenhagen Consensus had ranked global warming last on the list of the world’s ills. For one thing, the list is very incomplete (more on that below). For another, what the conferees were asked to rank were solutions, not problems. They were given three solutions to global warming, including the Kyoto Protocol, and didn’t like any of them.
But what a weird procedure! Not to ask the economists to rank the best solutions they could think of, but instead give them the solutions and tell them to rank them. So by his choice of solutions, the organizer could pretty much predetermine the results.
Another commenter asked: what makes me think global warming is the world’s most serious problem? Nothing; but it’s not what I think. The Copenhagen conferees were given a short, rather eccentric, list of problems; they were not asked what they think the most serious problems are. The list includes not only malnutrition, AIDS, and malaria, but also such things as water purity and trade barriers. In that list, it seems to me global warming is the most serious problem, though it doesn’t follow that we should adopt either the solutions put to the conferees, or any other solution: that depends on costs and benefits. Global warming would be very costly to arrest, so maybe we shouldn’t do anything about it, although for reasons I can’t adequately explain here but are spelled out in my book, I think we should.
If I were asked to list the greatest threats to the world, I would include global warming, but would add bioterrorism, nuclear terrorism, nuclear proliferation, biodiversity loss, cyberterrorism, nanotechnology, artificial intelligence/robotics, and asteroid collisions.
Asteroid collisions? I anticipate teasing comments asking me whether I’m also worried about invasions of aliens from other galaxies. (I’m not.) In fact the probability of a catastrophic asteroid collision, while small, has a greater expected cost than the $4 million that is all that NASA is spending a year to map NEOs (dangerous near-earth objects, i.e., asteroids whose orbits intersect the earth’s orbit. For a good discussion, see the report of the Task Force commissioned by the U.K.’s minister for science. It was less than a century ago that an asteroid a mere 60 meters or so in diameter exploded over Siberia with the force of a hydrogen bomb. Fortunately, the only casualties, so far as anyone knows, were the local reindeer. Maybe the next asteroid will explode above Los Angeles, sparing the reindeer. Of course that’s unlikely; cities occupy a minute fraction of the earth’s surface. But a slightly larger asteroid, wherever it landed, could inflict tens or even hundreds of millions of casualties from tsunamis, fire storms, shock waves, and dense clouds of debris that could block photosynthesis and even trigger catastrophic global warming.
A survey of global dangers, ranking them by expected costs, and analyzing cost-justified responses (if any), would be a great project, and one in which economists would play a key role. The “Copenhagen Conference,” however, strikes me as a parody of such an undertaking.