Hi Duncan,

Thank you for your tremendous effort to describe all the available CDR/NET
technologies together, in a comprehensive way such to allow a comparison.

I've been discussing biochar and rock crushing with Ron Larson and Oliver
Tickell; we concluded that there was scope for a combined method, which
could be scaled up to remove many gigatonnes of carbon per year at low
cost.  (We've used weight of carbon rather than CO2 in our calculations.)

I think you should have a separate column for benefits, because biochar has
several:  it improves soil, reduces need for fertiliser (thus avoids
considerable emissions), reduces water requirements, and is applicable in
poorer countries for improved, productive and profitable farming.

It is now recognised that ocean acidification could be far more serious and
more urgent than hitherto suggested, such that we'd need CDR to get the
atmospheric level of CO2 below 350 ppm within twenty or thirty years.  For
the first ten years, we'd have to build up CDR such as to cancel out global
CO2 emissions.  Then we'd have to ramp up CDR a bit further to actually
reduce the CO2 level.  I would like to see biochar take a significant role -
but it would require education and infrastructure projects to mobilise
farmers worldwide.

Cheers,

John

--

On Wed, Sep 21, 2011 at 12:11 PM, Duncan McLaren <[email protected]
> wrote:

> Group members may find my assessment of negative emissions
> technologies (NETs) of interest.
>
> The full report runs to about 100 pages, and can be found at
>
> https://sites.google.com/site/mclarenerc/research/negative-emissions-technologies
>
> A summary version written for Friends of the Earth (England, Wales and
> NI) will be published online later today.
>
> The assessment covers a wide range of NETs, but not SRM techniques. It
> considers capacity, cost, side effects, constraints, technical
> readiness, accountability and more for about 30 options.
>
> I'd be delighted to get feedback and comments.
>
> regards
> Duncan
>
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