Greg and Ron,
Indeed. Your letter could be more effective listing the known negative carbon processes. Just off the top, likely missed some, not listing the issues:
- Ocean Macroalgal Afforestation per N'Yeurt 2012 "Negative carbon via Ocean Afforestation."
- Biochar
- BECCS
- Olivine and other minerals (anyone know the speed of reaction with hot supercritical CO2 in hydrofractured minerals?)
- OIF
- Lime in the ocean
- Managing livestock for more soil carbon in plant roots
- Chemical "trees"
- Real trees (stored as lumber, artificial fertilizer sustains growth)
- Diatoms
---------- Original Message --------
Subject: Re: [geo] New climate article, peripherally related to CDR
From: RAU greg <[email protected]>
Date: Sun, May 05, 2013 10:14 am
To: [email protected], Geoengineering
<[email protected]>
--Thanks Ron. I agree that "irreversible" is a poor choice of words given that once we stop emitting fossil CO2, air CO2 and global T (+- inertia) will eventually decline back to pre-industrial levels due to nature's CDR, but in a time frame of say 50 kyrs. The paper does acknowledge that once we stop emitting, air CO2 will start to decline, but the possibility that we might be able to accelerate or augment this air CO2 removal is ignored. I'd say that this might be an opening for a letter to Science from the CDR community perhaps with the title "CO2: Reversible and Avoidable". Anyway, count me in.-GregAs for your wording, here's what I'd say, open to further discussion:Given the reversibility of air CO2 concentrations and hence CO2-induced
warming, every increment of reduced or avoided
temperature increase represents less warming [x, y]
that would otherwise persist for many
millenia (Archer et al., 2009). Because post-emissions (i.e., air CO2) removals
can return global CO2 and temperatures to preindustrial
levels, they do have the power to
avert additional warming or affect cooling on the same time
scale as the emissions reductions or removals themselves.
Climate warming tomorrow, this year, this
decade, or this century is predetermined
by both past and future CO2 emissions as well as the rate of CO2 removal.The climate benefits
of both emissions reductions and enhanced CO2 removal [CDR] will thus
occur on the same time scale as the political
decisions that lead to CO2 emissions reductions and/or CDR.One little caveat here is that CDR must operate by not only removing CO2 from air, but also in removing the excess, ocean-absorbed CO2 that will degas back into the air, al la Cao and Caldeira (2010). So the response of air CO2 conc to air CO2 removal alone will be (very) sluggish. This is why I'm a big fan of consuming excess CO2 in the ocean (via base/alkalinity addition). This addresses multiple birds with one stone: ocean-->air CO2 flux is reduced or reversed, ocean acidity is neutralized, and the bio effects (on calcification) of ocean acidity are offset by alkalinity addition. Given earth's past successes in mitigating excess global CO2 in this fashion, it would seem unwise to ignore Mother Nature's example, but I'm open to better ideas.-Greg
From: "[email protected]" <[email protected]>
To: Geoengineering <[email protected]>
Sent: Sat, May 4, 2013 3:06:48 PM
Subject: [geo] New climate article, peripherally related to CDR
List:--
1. I believe this article from last week's Science could be valuable to this list, although there is (close to) zero mention of either side of geoengineering:
Irreversible Does Not Mean Unavoidable; H. Damon Matthews 1 and Susan Solomon 2Science 26 April 2013: Vol. 340 no. 6131 pp. 438-439DOI:10.1126/science.1236372
2. I hope someone can help me understand the use of "Irreversible" in the title and, as an example, in the final paragraph:"Given the irreversibility of CO2-induced
warming ( 5, 6), every increment of avoided
temperature increase represents less warming
that would otherwise persist for many
centuries. Although emissions reductions
cannot return global temperatures to preindustrial
levels, they do have the power to
avert additional warming on the same time
scale as the emissions reductions themselves.
Climate warming tomorrow, this year, this
decade, or this century is not predetermined
by past CO2 emissions; it is yet to be determined
by future emissions. The climate benefits
of emissions reductions would thus
occur on the same time scale as the political
decisions that lead to the reductions."Cites 5 and 6 are:5. S. Solomon, G. K. Plattner, R. Knutti, P. Friedlingstein,
Proc. Natl. Acad. Sci. U.S.A. 106, 1704 (2009).
6. H. Matthews, K. Caldeira, Geophys. Res. Lett. 35, L04705 (2008).3. Believing that CDR is real and alive, I would have preferred to see this (my emphasis added) as:Given the reversibility of CO2-induced
warming, every increment of avoided
temperature increase represents less warming [x, y]
that would otherwise persist for many
centuries. Because emissions removals
can return global temperatures to preindustrial
levels, they do have the power to
avert additional warming on the same time
scale as the emissions reductions themselves.
Climate warming tomorrow, this year, this
decade, or this century is predetermined
by both past and future CO2 emissions and removalsThe climate benefits
of emissions reductions and removals would thus
occur on the same time scale as the political
decisions that lead to the reductions.My cites (x and y) might be from Jim Hansen and Bill McKibben, but also this list, the Royal Society and the new NRC study all of which describe various CDR approaches. All mistaken? I ask why this second version should not be the more accurate.4. In defense of the authors, whose work I otherwise uniformly admire, I think the intended word rather than "irreversiblity" might have replaced "ir" with (awkwardly) "non-utilized" or "un-utilized". The "ir" strikes me as guaranteeing a physical impossibility, for which no proof is offered. I think this important as CDR gets too little attention anyway, to be saddled with "irreversible"Thoughts?Ron
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