The Summary for Policymakers of the UNEP/WMO report, which is all that I think is so far released, is at http://www.unep.org/dewa/Portals/67/pdf/Black_Carbon.pdf They basically discuss something like 16 key emissions reduction targets to focus on first or most aggressively (or maybe just to show the potential as there are quite a number of other sources they could have mentioned.
Best, Mike On 5/12/11 12:23 PM, "nathan currier" <[email protected]> wrote: > Thanks, Mike, for the excellent responses, with which I agree 100%. Do you > have handy a link to the new UNEP assessment you mention? I'd much like to see > it. > > One of the things that often perplexes me is why CCS from burning coal at a > plant is generally > considered geoengineering, but trapping the methane that escaped in mining > that very same coal > is generally not. For purposes of this site, where thinking is on a much > higher level than in general climate discourse, I hope that we can consider > both equally to be "geoengineering" (or neither, I suppose, depending on how > one wants to define geoengineering). > > In any case, a major point of mine for a number of years now has been that the > best, safest, cheapest, way to cool the planet quickly (at least to help put > off tipping points into the future, if not enough to avoid them altogether, so > that SRM, etc, would be ready) will likely be shown to be rapid methane > emission declines (or CH4/BC). In the past I've written here my own estimates > of what is possible - rough amounts, their resulting radiative forcing effects > and evolution in time-scale, and their costs - saying that the maximum amount > that could be spent now is ~$250 Bn. > > But economics works on minimums, of course. The M2M (now GMI) program has thus > far only been spending about $10Mn/yr for a half decade, or $50Mn. But they > say that this spending has leveraged $387Mn in total project investments (or a > 7.7x leveraging). Clearly $250 Bn wouldn't really need to be spent. Since one > wants to insure maximum speed, one can guess that actual spending would need > to be > $32.5Bn, but even assuming just a three-fold leveraging, ~$80Bn total > could probably achieve about the same as the $250Bn, a relatively pronounced > near-term forcing decline for the arctic (i.e. effects beginning to be felt in > a few years from onset of program). Were there even a mild carbon market price > of $14/t CO2e, the methane trapped that I am talking about would have a > ~$40Bn/yr value, and even without any such market, it provides a formidable > income stream (which is why governments, international corporations and > lending institutions, etc, have so greatly leveraged the rather meager US > investments). > > So, even just $5-8Bn from each of a dozen wealthy nations might be enough to > make a HUGE difference in our current emergency, if we can figure out how to > make this into an appealing "methane game." In recent posts, people have been > talking about how to trap methane down in the arctic taliks and so on. At > present there's an estimated total of ~8 MMt/yr coming from there, and it > would be a most messy business, but easily well above 10x that could be > trapped quickly through currently planned projects, while also providing an > appealing profit stream, all around the world, and probably having more > climate effect/t, since it would effect the larger ocean/air currents entering > the arctic from outside that are a large part of what's pushing it out of its > current state. > This is the best "geoengineering" we've got at the moment, I believe. Call it > "methane CCU" - carbon capture and use, that is - if it feels more like > geoengineering that way. Again, a total -RF equal to some 1/3 of the net > positive forcing is at stake with this approach. > > In terms of Michael Hayes' comment, > >> The notion of un-known/hypothetical feedbacks denuding SRM efforts is >> interesting. In that, it is injecting a double-false conditional into the >> debate. This is more of a media tool than a scientific one. > > I'd like to mention something that partly underscores why I continue to say > that methane seems like the real key, more than BC, even though some BC > sources are cheaper per unit of -RF. BC is quite complex and gives both > positive and negative forcings, and has its positive forcing increased when in > a general mix of negative forcing aerosols. That's precisely the kind of > feedback that Hayes is dubbing hypothetical - it isn't, but such > aerosol/aerosol interactions are vastly problematic to ever get a precise > handle on, so it makes things less certain in terms of resulting effects (both > for BC reductions and for any SRM done at an altitude where it could interact, > by the way, if Ramanathan's very large 1W/m2 BC forcing is right). I much > agree with Drew Shindell at GISS, in his saying that methane reductions have a > very low level of uncertainty. (That being said, taking down the 20% or so of > BC from very inexpensive to change sources around the Himalayas should > obviously be one of the very first things that we do, if possible.) > > So, in terms of Andrew saying he's much more "gung-ho," I'm not convinced. I > quite agree with the despondent tone of some recent posts, suggesting that > even full-scale SRM might become ineffective, if we let the arctic go too far > on its own. So, to truly get gung-ho, what we all need now is to switch gears > a bit - sure, keep thinking about "boil and bubble, toil and trouble" > brightwater innovations and so on - but what we REALLY need to figure out is > how to get ASAP some $50-80Bn going on a global methane project. Could the UN > start a new program, a "game" taking off from the GMI with 15-20 countries > putting into a kitty, and a central structure putting together > high-incentivization loan schemes in target countries (i.e. with > "lowest-hanging fruit" projects) to allocate from it? If one wanted it to be > "free," like the recent US bailouts, all players could then be paying > something back on their profit streams over a multi-decadal period, ultimately > paying back the original investors. So, a 20 yr plan that aims to have maximum > methane draw-down up front, but works so that the largest initial investors > get all or most of the investments back near the end. Maybe we don't need much > US money to get it going, if the US would be hard to get anything from. China, > UK, Eurozone, etc, could be the largest initial investors, perhaps? > > Cheers, Nathan > > > > > > > > > > > > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en.
