Pinatubo was the name of a volcano in the Philippines that had exploded in 1991. It had blasted fifteen million tons of sulfur dioxide into the stratosphere. The result had been a couple of years’ beautiful sunsets and reduced global temperatures. The two phenomena were directly related. The sulfur from the volcano had eventually spread out into a veil of tiny droplets of H2SO4. Light from the sun hit those little spheres and bounced.
