... and, in addition to Nick's post, there is one key phrase in the whole of your post:

> With a concerted will we can reverse our wasteful use of space and
> create offsetting green carbon sinks which can suck up the higher levels
> of carbon dioxide, the greenhouse gas heating us up - while pumping out
> more oxygen.

"With a concerted will".

Even a simple scan of the headlines on any given day shows that this is
not going to happen.

If there is no "concerted will" to stop people killing, maiming & generally causing
pain to each other, no "concerted will" to stop the exponential growth in population
(despite the obvious fate of the children being born in most cases), no "concerted
will" to rebalance the obscene differential in wealth & living standards - all of which
affect millions of people every day - then there is no chance of getting any
"concerted will" focussed on a problem whose true impact is yet to hit home and
which will require total cooperation for *decades* to even turn around.