[Leica] Global dimming and photography

[rdcb37 at dodo.com.au (Rick Dykstra)]

So there's this thing called Global Dimming, caused by soot and 
particles from exhausts, aero engines and industry, which has caused an 
increase in clouds (reducing the immediate impact of Global Warming) 
and causing a major reduction in the amount of sunlight reaching the 
surface of the earth.  It must be true - I saw it on telly.  It was the 
immediate aftermath of 9/11 that brought it to prominence - the skies 
were suddenly much clearer without all the air traffic - and 
temperatures rose noticeably.

Anyway, the measurable differences in light levels in various places 
around the world, now vs 50 years ago, is huge.  Like 15% on average 
and up to 25% in some places, such as Russia.

So, has anyone noticed the difference? Do the rule on thumb exposure 
methods leave you with underexposed shots now?  It was Doug's post on 
using an SL body for K25 that prompted me to mention this.  Is there 
enough light anymore for such slow films?

Maybe Global Dimming will be Leica's salvation - fast lenses will be 
all the go.  ???

Rick.