At the extreme end of environmental damage, there are some low-probability high-impact disasters that can only be prevented – there is no way to recover from them, because they would be so destructive that there would be nothing to recover. The most notable of these is the possibility of a civilization-ending meteor strike, like the dinosaur-killer that hit Earth 65 million years ago. This is not at the top of anyone’s worry list, but since the Chelyabinsk explosion and the multiple meteor near-misses in 2012 and 2013 there has been growing pressure for the US and other rich nations to conduct a massive census of Earth-crossing asteroids and to develop plans and an actual capability for diverting large rocks that are found to be headed our way.
US leadership in such a project fits with our pattern of leadership, financially and scientifically, in environmental areas like epidemiology, vaccine development, environmental testing, satellite mapping, earth data, global weather data and climate research, and many other areas that have benefited the whole world. These are just some of the ways we earn the acceptance of the rest of the world for our claimed right to set standards for global behavior and to impose sanctions on rogue states. But none of these are cheap.