Too long for comments section... again There are many little points I want to make here, now that we're at a more godly (pun) hour. - Godless points out that Lomborg uses UN data. Since when is UN data reliable? - Godless's math gives him the extinction of 4.9 percent of species. This is for direct wipeout, though -- it doesn't account for the ramifications a 4.9 percent loss would have for the other 95.1 percent of organisms on the food chain that depend on the 4.9 percent. And dependence, of course, isn't just about eating. There could be symbionts lost, or organisms that depend on other complex behavioral webs that we don't even know about. - "The extinction rate will probably be dwarfed by the discovery rate." I doubt it. The species we haven't discovered yet are the ones that aren't very common. If we're already managing to take out the more common ones -- which should theoretically have a better chance of surviving thanks to sheer numbers -- how can you assume the less common ones are going to still be around? Especially given how heavily they probably depend on the common ones? - "Was the asteroid that killed off the dinosaurs evil? The mass extinction did, after all, make way for the mammals." Sure. After several million years, it did. The pace of evolution is so slow that we won't see a new mammal analogue rise in the human lifetime. (And hell, if it did, we'd probably kill it off. I think we've got a pretty good grip on biological hegemony. Even if the "new mammal" were something that evolves fast, like bacteria, we're hard at work trying to figure out how to kill those too...) - "Does Wilson think that there is some mystical value in biodiversity?" I dunno. I'd be willing to bet he subscribes to something similar to Gould and Einstein's philosophies on nature -- should be celebrated because it exists. (It's not an Earth-Mother type belief so much as a crystallization of that feeling we all get when we learn something fascinating and new.) But even if he doesn't, you can make the argument that nature should be studied because it exists. And it's hard to study it if it ain't there. - "Mankind has introduced a lot of diversity. ... Look at how many mammals (sheep and red deer prominent among them) now roam New Zealand, or the wild horses in the American west and camels in Australia." Does knocking something else out of its niche and replacing it with an intercontinental transplant count as "introducing diversity"? If that's the case, then we should applaud the introduction of zebra mussels in the Great Lakes. Species invasion isn't about introducing diversity; if anything, it's about decreasing it. - We should all discuss this over drinks sometime. Game, set... and cheers!