In sci.space.policy Rand Simberg wrote:
On 16 Mar 2006 08:50:26 -0800, in a place far, far away, "bill"
made the phosphor on my monitor glow in
such a way as to indicate that:

"George" wrote in message

He also assumes that the environment in which we all live could sustain
such levels. I don't think there is any precedent for that assumption.

I don't think plants will complain.

How do you know? The planet has never sustained those levels.

800 ppm?

800 ppm will easily desertify the planet and melt all the ice.

increased temperature accelerates the evaporation precipitation
cycle, really, you are looking at more tropical type climates and less
desert.

Not to mention the fact that it would probably accelerate plant growth
rates (and in fact such acceleration would prevent the levels from
ever getting that high).

I remember reading a study somewhere that plant growth doesn't
accelerate that much with increasing CO2 concentration. It is a factor
that can slow down global warming slightly, but not much. I don't have
references.

Also, 1-3.5 degrees C is equal to 150 to 550 kilometers of distance
towards the equator - trees can have trouble adjusting and might
get massive disease outbreaks. This has happened somewhat in northern
areas when some parasites' larvae don't die anymore since the
winters tend to be warmer than before.

Actually, I've read that human activity is causing the sixth mass
extinction as we speak.