[lysp]

> There are good reasons to green-up our cities, but global CO2 levels isn't one of them.

I believe they can to a point. Trees, parks and greenery lower the average temperature for an area. Less heat being absorbed.

This would likely leads to less of a need for cooling and energy use.

That being said, I don't remember reading about how much of an effect it does have, just that it's not zero.