On a flight from Kuala Lumpur to Kota Kinabalu, 24 March 2009, I caught a direct visual impression of the Asian Brown Cloud — brown haze below, blue sky above. I immediately used the resulting images in the keynote speech I gave there, in two slides, as part of a section on the need for good indicators.  “Sometimes we can see what’s happening with our own eyes … and sometimes we can’t.”