On Thu, 17 Sep 2009 22:14:48 +0100, Norman Wells wrote:

And wouldn't it be better to use trees as we always have?

No, because trees rely on natural air movement to access the
atmosphere, not forced air movement. And they tend to decay or be
burned, releasing their captured CO2 in the timescale.

How much energy do you think that will involve? How will these 'scrubbers'
work exactly, and how will they be powered?

Electricity... coming from power stations... powered by coal or gas.
It's bleedin' obvious innit?