Oh Dear….

CJ
#1. July 12th, 2008, at 3:47 PM.

You correctly note that air quality in North America has improved significantly since the 1970s. It certainly has improved in Vancouver, where late-afternoon brown-orange smog was regularly visible over Burrard Inlet in the late 70s and early 80s. However, young people often seem to have difficulty believing this. The geenwashing of their brains has convinced some of them that things are getting steadily worse and we are now at some kind of a critical point.

Renee
#2. July 13th, 2008, at 6:42 AM.

Which would tend to account for pretty much all of the effect that Jim Hansen and the team have claimed to observe …

Interesting interpretation of “at least half.” Especially since the other half is exactly what was predicted. Yeesh. The actual study itself says this:

With respect to the temperature evolution in central Europe, increasing aerosols were apparently effective in masking greenhouse warming after the 1950s [Wild et al., 2007], whereas the observed direct solar forcing due to the strong aerosol decline since the mid-1980s has reinforced greenhouse warming, although the reduction of absorbing aerosols (such as black carbon) might have dampened the reinforcement.

Wild, another researcher at the same institution (they all seem to co-publish at various times), is quoted at a conference where he presented a similar paper as saying this:

Crucially, the stability of smog levels also suggests that ever-cleaner air cannot be the cause of increasing temperatures. Satellite data shows that overall the continents have warmed by 0.04 °C per year between 1999 and 2007. This, says Wild, could be the true, unadulterated signal of man-made global warming.

UVic is just up the road. Stop by the library some time…