Global Darkening

Doom May Loom Amid The Gloom In the second half of the 20th century the world became, quite literally, a darker place. Defying expectation and easy explanation, hundreds of instruments around the world recorded a drop in sunshine reaching the surface of Earth - as much as 10 per cent from the late 1950s to the early 1990s, or 2 to 3 per cent a decade. ... the dimming trend - noticed by a handful of scientists two decades ago, but dismissed at the time as unbelievable - is now attracting wide attention. Research on global dimming and its implications for weather, water supplies and agriculture will be presented in Montreal at a meeting of US and Canadian geological societies next week.

I'm not so surprised to hear about this possibility. The mechanism -- light blocked by pollution -- seems straightforward enough. I'm reminded of the discovery of the ozone hole. Scientists initially couldn't believe the data because it was so much bigger than anyone would have anticipated, but it turned out to be legit.