geoengineering Google Group

Re: [geo] Re: Rejected - a simple argument for SRM geoengineering AND did you get that right?

mmacc...@comcast.net (Mike MacCracken) — Sun, 22 Nov 2009 20:29:33 UT

Dear Peter‹Agreed, the residence time of a particular CO2 molecule in the
atmosphere is a few years. And this number was confirmed in the 1950s/60s
following the atmospheric nuclear testing as the excess C-14 molecules were
taken up by the ocean and biosphere.

But what matters for climate is the lifetime of the perturbed concentration,

Re: [geo] Re: Rejected - a simple argument for SRM geoengineering AND did you get that right?

pre...@attglobal.net (Peter Read) — Sun, 22 Nov 2009 17:32:40 UT

Re: [geo] Re: Rejected - a simple argument for SRM geoengineering AND did you get that right?Hi Mike

Don't think so. Rereading my message I see that I did not omit to mention both the deposit and withdrawl mechanisms for the "biosphere carbon bank" i.e. photosynthesis for deposit into the biosphere 'bank' and decay for withdrawl from it. The gross flows of about 110 Gt each into ocean and terrestrial biosphere are netted off in the numbers I quoted, with about 50Gt respired immediately by plant life and about as much released by warm oceans as is absorbed in cold ocean regions (more exact numbers at Fig 4 [3?] of the RS geo-engineering report that I don't have to hand).

Practical hardware for stratospherics

s.sal...@ed.ac.uk (Stephen Salter) — Sun, 22 Nov 2009 16:23:31 UT

Peter

Thank you for your cockle-warming words.

Work on the mechanical design of most difficult inside bits of the spray
vessels has reached a point where little more can be done without some
money for test rigs. I can give you part numbers for bearings, seals,
and tell you the temperature of the cooling water. It would be a mistake

Re: [geo] A simple argument for SRM geoengineering, again.

pre...@attglobal.net (Peter Read) — Sun, 22 Nov 2009 07:27:53 UT

Re: [geo] A simple argument for SRM geoengineering, again.I used sulphate as an example because my understanding is that this is the only SRM technology that we are confident would work. I think your interesting recent paper confirms that view, although it mentions a number of other technologies that look very interesting.

Re: [geo] Re: Rejected - a simple argument for SRM geoengineering AND did you get that right?

kcalde...@carnegie.stanford.edu (Ken Caldeira) — Sat, 21 Nov 2009 19:00:52 UT

Be aware that that formulation of Vaughn and Lenton is a simplification and
that 20% asymptotic value and 40% is probably a better estimate for
cumulative releases on the scale of conventional fossil fuel resources.

See attached paper for discussion.

______________________________ _____________________

Re: [geo] Re: Rejected - a simple argument for SRM geoengineering AND did you get that right?

agask...@nc.rr.com (Alvia Gaskill) — Sat, 21 Nov 2009 18:40:19 UT

Re: [geo] Re: Rejected - a simple argument for SRM geoengineering AND did you get that right?From Lenton and Vaughn (2009):

"First we consider the calculation of effects on atmospheric
CO2 (deltaCatm) over time. Adding CO2 to the atmosphere or

removing CO2 from the atmosphere triggers responses from

Re: [geo] Re: Rejected - a simple argument for SRM geoengineering AND did you get that right?

mmacc...@comcast.net (Mike MacCracken) — Sat, 21 Nov 2009 13:56:14 UT

Hi Peter‹Problem with your analysis is that biosphere also gives off
something like 60 GtC as well. Preindustrial with steady CO2, as much was
being taken up and given off. The net uptake, driven by the gradient created
by emissions is now something like 1 GtC/yr and would equilibrate well
before all of the perturbation is removed for this net uptake is occurring

Re: [geo] A simple argument for SRM geoengineering, again.

r2007...@gmail.com (Raymond Law) — Sat, 21 Nov 2009 10:57:58 UT

*Hi John,*

I have said that your train of logic is just what we would be needing
today. Go for your *manifesto,* I am all for it !

We have been talking about long term solutions for too long, let's act on
the immediate term solution from *John * -- this might even buy us time to
come up with a set of really good long term solutions, too.

Re: [geo] Re: Rejected - a simple argument for SRM geoengineering AND did you get that right?

pre...@attglobal.net (Peter Read) — Sat, 21 Nov 2009 08:20:59 UT

RE: [geo] Re: Rejected - a simple argument for SRM geoengiI must be off the map somewhere I guess, but in my view you guys have got it wrong

This is because the calculations pertain exclusively to atmospheric physics/chemistry.

In fact the biosphere fixes about 60 Gt C annually plus another 20 including oceanic photosynthesis

Re: [geo] A simple argument for SRM geoengineering, again.

pre...@attglobal.net (Peter Read) — Sat, 21 Nov 2009 07:24:19 UT

John

If it is to impact on policy -- I guess policy-makers are the intended audience but how to get the message to them is another question -- it is important to realise there are quite likely a fair number of deniers out there. It is no good just saying [or implying] they are wrong since confrontation is not good conflict resolution.

Re: [geo] A simple argument for SRM geoengineering, again.

kcalde...@carnegie.stanford.edu (Ken Caldeira) — Sat, 21 Nov 2009 06:08:51 UT

John,

In my experience, the best way to develop a broad sign-on letter is for
someone to write a first draft, and then assemble a small core group to
carefully hone the message, and then send it out to a broader group with a
simple yes/no offer to sign on (unless some egregious or easily corrected

Re: [geo] A simple argument for SRM geoengineering, again.

rongretlar...@comcast.net (Ron Larson) — Sat, 21 Nov 2009 04:56:56 UT

John - Sorry I haven't responded earlier. I think I can speak for
quite a few others in the "Biochar tribe" when I offer below some
comments on what you have written. I do wholeheartedly agree with the
thrust that we are not doing enough today.

Re: [geo] Re: Rejected - a simple argument for SRM geoengineering

wig...@ucar.edu (Tom Wigley) — Sat, 21 Nov 2009 00:17:59 UT

Dear all,

How important is methane? This is not a simple question to answer.

But in my attached 1998 paper I conclude that 100-yr GWPs **underestimate**
its importance by a factor of 3.

GWPs are seriously flawed. See the papers below, but there are others
by other authors (Harvey, Shine, ...)

A simple argument for SRM geoengineering, again.

j...@cloudworld.co.uk (John Nissen) — Fri, 20 Nov 2009 23:43:54 UT

Hi Jim,

I want to follow up on your email of 15th November.

So far, nobody has challenged the logic of my argument. So we all seem
to be in agreement! It's not what we'd like to believe, but the
conclusion is clear.

Why are most academics among us so reticent? Jim Hansen has noticed

RE: [geo] Re: Rejected - a simple argument for SRM geoengineering

marty.hoff...@nyu.edu (Marty Hoffert) — Fri, 20 Nov 2009 23:00:26 UT

David et al:

True, Jim Kasting's work on the long-term carbon cycle as impacted by
human fossil fuel CO2 emissions is decades old. But brilliant though
Jim is, he was not the first. See, e.g., the attached paper published
in 1974 when it first dawned on me and others at NASA/GISS that we
might be on to something important with the fossil fuel O2