Paul Martin wrote:
In article ,
Steve Thackery wrote:
That one's been already cracked. It's called a tree.

Nope, doesn't work, and one of the greatest green myths of all time.
Everybody knows that trees absorb CO2 when they grow, converting it into
plant mass.

Unfortunately, every living tree eventually dies, rotting away. As it rots,
it releases all the CO2 back into the atmosphere again. The same is true if
you burn it, of course.

The only way a tree can make a lasting contribution to CO2 reduction is if
we cut it down when it is fully grown, and then either store it in such a
way it can never rot, or drop it into a subduction zone so that it releases
the carbon so deep in the earth it can never escape again.

OK, so you store it, just like you store the CO2 captured by other
means, eg. building materials. How much CO2 does roasting limestone for
cement liberate?

I think a lot goes back into it when the cement sets again..