Anyone here remember the days when the percentage of carbon dioxide in
atmosphere was an awful lot more than it appears to be at the moment?

I should hate to be left out on a limb by misremembered information
from my youth. It took enough effort getting the facts in there, I
shall be bloody annoyed if they were wrong.

Not that it would make much difference. For all the best laid plans of
mice and men, that set of people who set up home in a sealed dome gave
up after all their carbon dioxide was depleted by the concrete.
http://en.wikipedia.org/wiki/Biosphere_2

A different take on it he
http://www.thespacereview.com/article/305/1
Is Kylie Minogue British?

Don't answer that. I would prefer to believe I am not the only one who
isn't absolutely sure.

Now here is an oddity:

"CO2 concentrations in central Phoenix are currently 500-600 parts
per million. That's what it will be globally in 50 years. So it
allows a natural lab experiment to take place," says Idso.

Add to this the fact that Phoenix has an urban "heat island."
Afternoon temperatures are 3 to 5 degrees Celsius (5 to 9 degrees
Fahrenheit) above surrounding areas. Together, more CO2 and hotter
temperatures add up to a pretty good example of what most cities will
experience in the future.

http://researchmag.asu.edu/stories/co2.html