Re: [asa] Relax, CO2 is Good for You!

On Wed, Sep 30, 2009 at 7:38 AM, David Clounch <david.clounch@gmail.com>wrote:

> Bill,
>
> Apparently we have been about 3 degrees F colder because of human induced
> global dimming. Cleaning up air pollution will have a devastating effect on
> climate. This is the warming that absolutely is human induced, no doubt
> about it. I mentioned global dimming once on the list, nobody said
> anything.
>
> -Dave C
>
>
>
>
First of all, where did you get that number it sounds awfully high. There
are key differences between sulfate aerosols and CO2.

1. Sulfate aerosols have a mostly local effect while CO2 has global effect.

2. The size of the effect of sulfate aerosols is smaller than CO2. In the
early 70s we knew CO2 warmed and SO2 cooled but we didn't know the relative
strength. Once the early computer models in the mid-70s came out it became
clear that the warming would predominate. The other reason the effect of SO2
was overestimated in the early 70s is they couldn't have predicted how
successful SO2 cap and trade would be in the Bush I administration.

3. Most importantly the lifetime of sulfate aerosols in the atmosphere is
short lasting -- a few years -- while CO2 lasts centuries to millennia. The
bulk of climate effects of reducing sulfate aerosols have already happened
and any new effects of further reductions will be nominal. Other aerosols
such as black carbon aerosols caused by burning biomass have a modest
warming effect. There is still a lot of CO2 effects already "in the
pipeline". if we magically dropped CO2 emissions to zero we will continue
warming for decades to centuries into the future until we reach
equilibrium.

The CO2 is good of us meme has been promoted by the denialist community for
decades now. The astroturf organization, the Western Fuels Association,
produced "The Greening of Planet Earth" in 1992 which argued that CO2 was
good for us.

http://www.amazon.com/Greening-Planet-Earth-Western-Association/dp/B0018BUJUQ

On the other hand, the following study shows the devastating effects global
warming will have on U.S. crop yields, particularly under the BAU (business
as usual) scenario.

http://www.pnas.org/content/106/37/15594.abstract

Holding current growing regions fixed, area-weighted average yields are
> predicted to decrease by 30–46% before the end of the century under the
> slowest (B1) warming scenario and decrease by 63–82% under the most rapid
> warming scenario (A1FI) under the Hadley III model.
>

Rich Blinne
Member ASA

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Received on Thu Oct 1 11:09:05 2009