Let me begin by congratulating you on your ongoing effort to bring climate change closer to your readers. In your current issue, you dedicate a leader and the entire Science and Technology Section to this topic (“Piecemeal Possibilities” and “Climate Change in Black and White,” February 19, 2011). As it transpires, pollution is not exactly a blessing for those who have to live with it, but it also cools the planet. In particular, sulphur given off by coal-fired power stations is very good at forming reflecting aerosols that provide a cooling effect. Now and then, volcanoes do the same. Paul Crutzen, a Dutch climate scientist who was one of the first to theorize about “nuclear winter,” which won him a Nobel prize, is thus proposing that sulphur be put into the atmosphere by means of geoengineering. Now, this brings us to the crux of climate change: how are we to govern our response? Although the issue of governance was not at the focus of your article, perhaps it ought to be. Three-page articles about science are not likely to win you many readers, and especially mighty ones, but the discussion of our response to climate change most likely will. And the main problem with geoengineering is that it is palpably about the whole world rather than a few countries, no matter how rich and powerful they may be. This is where science, engineering, and politics will have to meet. Worldwide, as well. How is this to be achieved, though? And what are the odds of getting there? Such a discussion should guide the best of science and engineering, as well.