I’m a supporter of geoengineering, but occasional comments here seem
misguided to me, when they refer dismissively to emissions reductions
as useless for the near-term (like John Gorman’s from last week),
since they consistently overlook the potential of the short-term
forcers in climate control, and are only looking at CO2. I’d like to
briefly review just what is really possible through this approach, for
his benefit as well as others posting here of like mind, because
understanding what’s easy and practical right now through emissions
control should be guiding our geoengineering goals. Even the Royal
Society, describing its upcoming geoengineering meeting, it seems to
me begins in error:
Society seems unable or unwilling to make the drastic reductions in
CO2 emissions necessary to avoid dangerous (unacceptable) climate
change. A new science "Geoengineering" that until recently would have
seemed pure science fiction, promises an alternative way of
temporarily regaining control of climate.
But if our goal with geoengineering is, in fact, TEMPORARY regaining
control of climate, that is also achievable to a considerable degree,
for a short period, through sharp methane reductions. December saw the
formation of the new Global Methane Fund at Copenhagen, with Robert
Watson, the former head of the IPCC, as its leading voice: “We need to
get moving to cool the planet’s temperature. Methane is the most
effective place for us to start,” he stated. I agree. Geoengineering
plans should be conceived around what cannot be accomplished once non-
CO2 reductions are taken into consideration (which would likely push
geoengineering further into the future, and thus possibly alter its
nature and goals). I feel sure that there will still be a crucial role
for geoengineering, but with frequent discussion in this group of the
immediate dangers of methane release from submarine hydrates, etc., a
fundamental question that needs to be asked here is just how
geoengineering compares with attacking our own anthropogenic methane
inputs for the time being, towards achieving this initial goal of
saving the arctic.
Of course, methane reduction has its limits, both in time and extent.
The immediate ceiling, I believe, would currently be about a 33%
reduction of total anthropogenic emissions, based on an expanded M2M
program (the EPA Methane to Markets program). In terms of time, it
should not lead to leniency with CO2 reduction beyond a few years,
ideally (for several years, I believe, forcings could match the IPCC-
recommended 40% by 2020 reduction curve with no CO2 reductions at all,
without even taking into consideration particulate decline issues).
The total cost, based on EPA M2M figures, with some expansion of that
program into a higher marginal abatement bracket for each of its four
categories, would be about $225 billion. Since People like
Schellnhuber and Gore have been talking about an ‘Apollo style’
project for energy, I think of this approach as the ‘Methane Apollo’
idea.
What would be its forcing impacts? Reducing about one third of current
emissions (I’m using a median figure here of ~360 Tg/yr, in the middle
of the different major inventories) would, I believe, lead to
restabilizing its concentration at about 1250ppb.
[from IPCC, 1995, p.117, roughly each -37Tg/yr emissions = ~ -170ppb
concentration]
(so, -120Tg/yr = restabilization at ~ -540ppb, and thus
1790ppb – 540ppb= ~1250ppb)
Thus, this should lead to a reduction, I believe, of roughly half of
our added methane forcing over the adjusment time. If we take the
recent “emissions-based” work of Shindell (Shindell et al, 2005), the
total methane forcing with its extended indirect effects is as large
as .8 to .9W/m2. So, we could quite reasonably get ~ -.4 W/m2 from
methane alone. If we add in a BC reduction program, from a .2 W/m2
total for BC, we’ll say we could possibly get about ~ -.1 from it. So,
a short-term forcer program could rather quickly achieve about ~ -.5 W/
m2, or about 32% of total net forcing (the current net forcing is
~ +1.6W/m2).
Some might think that this kind of rapid methane reduction will happen
in any market system, as soon as there is a price on carbon, but
actually not more than a third of this level would be likely to be
reached by 2020 unless either the 20 year GWP was used (unlikely) or
the price of carbon rises much higher than expected. I do agree with
John Gorman that CO2 reduction is certainly not going to help us right
now, but not just because the strategies are only “organized
hypocrisy.” There is an inherent problem: it is estimated that global
SO2 emissions in the NH dropped from somewhere between 10 and 20 TgS/
yr during the period 1980-2000, contributing a considerable (hard to
quantify) positive forcing effect. In the unlikely event that Gore’s
‘Apollo’ plan were enacted now, something approaching the lower end of
this estimate (about 8Tg S/yr) would be reduced again, in only half
that time period, and I doubt that SO2 market forces would be very
helpful in avoiding major warming spikes.
I’m well aware that, with CO2 increasing so rapidly now, short-term
forcers could only create a short-lived respite from warming unless
CO2 emissions start rapidly coming down as well. But work from GISS
(again Shindell) suggests that in fact the arctic would be
particularly strongly impacted through this approach, in large part
due to O3’s larger impact there and methane’s marked influence upon
it, as well as to the strong BC impact there. Thus, more than 1/3rd of
the anthropogenic forcing in the arctic should be capable of being
temporarily rolled back through this approach, helping return the
region to its familiar state for the time being.
My $225 billion figure is extremely close to the Copenhagen Consensus
Center’s “$250 billion question.” Indeed, one of the Copenhagen
Consensus Center’s 21 papers, to examine the ‘costs and benefits’ of
different $250 billion solutions to global warming over the coming
decade, looks at just this kind of methane approach. It’s worth
mentioning the paper, written by two German economists, only for its
glaring faults – it exhibits the all-too-common misunderstandings of
RFs and timing, particularly common from some economists, that end us
up with no alternative but immediate geoengineering. They surmise:
If the global community wanted to spend an even larger amount of
money – say, $250 billion – on methane mitigation, much larger
mitigation potentials could be realized, even such with very high
marginal abatement costs. Nonetheless, this approach would be
economically inefficient.
The paper uses the 100-year GWP throughout, making it useless in
considering either the economic value or the real near-term RF impacts
of the approach. At least everyone taking part in these discussions
surely appreciates the potential for huge and lasting economic value
from temporary climate effects in a time of crisis, and the importance
of the avoiding positive feedbacks. Indeed, a problem with John
Gorman’s suggesting that we should be doing SRM right now is that it
is, in a sense, even economically better to concentrate on methane
emissions, aside from being inherently safer. Think of it this way:
everyone agrees that these methane emissions need to be cut. But by
simply initiating this least expensive part of GHG reductions quickly
we can fulfill, at least for the time being, much of the ‘climate
bridge’ function to which many now are starting to ascribe the
necessity of geoengineering. And these one-time costs confer
continuous RF savings, unlike costs for SRM.
You might say that I’m a dreamer, and that it will be impossible to
get the world to really enact such an ‘Apollo Methane’ idea in time to
save the arctic. But we know exactly what to do, already have many
projects shovel ready, and we know that they are 100% safe and surely
will be effective. Do you really think it will be easier to first
develop and then refine SRM, and then get the whole world to accept
it, faster than that? I don’t deny that negative forcing effects can
be felt by far the fastest with particulates, once you finally release
them, but the more I have thought about it, reading these discussions,
the more convinced I am that it might be that the only way to really
save ourselves in the arctic is through non-CO2 emissions control:
once the time frame of basic research plus developing the political
frameworks for agreement are added together, it seems that the
fastest route to reducing arctic forcing will actually be through non-
CO2 emissions reductions, not SRM geoengineering.
Looked at from this point of view, the emerging emphasis of
geoengineering centered on SRM could turn out to be something of a
miscalculation. I am not opposed to SRM, but see it as a last resort
– a climate ‘band-aid’, prudent to develop, but hopefully not to be
used widely, always involving side effects involving hydrology, and
diverting much-needed financial resources towards short-lived
benefits. Once one considers short-term forcer control in the mix,
then the scales might tip more towards CO2 direct air capture,
biochar, etc. That being said, I am certainly not against immediate
research into SRM, but I hope that it will only get used much further
down the road than several posters here would seem to want.
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