Hi Michael and Wil--It is, of course, not one or the other. If the Earth's temperature is to be limited to less than some value (2 C per the Copenhagen Accord, and given what is happening at 0.8 C there is good reason to think the ceiling should be lower), no one strategy will do--we need all that are available. In addition to adaptation, it would seem the steps need to be:
1. Sharply reducing CO2 and other long-lived emissions from fossil fuels and deforestation is critical to limiting long-term warming (as the NRC Stabilization report makes clear). To the extent we don't do this, it extends and intensifies the requirement for everything else. 2. Sharply reducing CH4, ozone precursor, black carbon, HFC and other short-lived emissions is critical to slow the rate of warming over the next several decades, as made clear in the recent UNEP/WMO assessment (and in an overshoot diagram in the NRC stabilization report). 3. Carbon Dioxide Removal through a range of processes is critical to reducing damage from ocean acidification and to shorten duration of time with high levels of CO2. 4. Even with all of these, is seems quite plausible that tropospheric/surface Solar Radiation Management (quite possibly regionally applied and focused on countering specific impacts) might well be appropriate. For example, it might be useful to invoke to continue the existing cooling offset of sulfate aerosols and to at least moderate polar warming in order to help limit loss of ice sheets and mountain glaciers, to sustain permafrost and limit methane release (other applications might be seeing if one could slightly redirect storm tracks by adjusting sea surface temperature gradients, or limiting tropical cyclone intensification by cooling critical regions, etc.). The level of SRM here would, assuming the first three approaches, not need to be near the equivalent of reversing a CO2 doubling (as most calculations have been focused on), and so it would seem, so still to be tested, likely to have not nearly the unintended consequences of global stratospheric SRM. [And in this category as well might be the buffering of ocean waters in critical sub-regions as discussed in other emails.] 5. It seems to me that global stratospheric SRM, which has received the most attention, and seems to be envisioned by most as being invoked on an emergency response basis after all of the above (plus adaptation) have been pursued and there is still some crossing or near crossing of a key threshold (e.g., permafrost and clathrate methane seem very near massive release, etc.) right ahead. At that point, even with there being some significant losers (e.g., storm track or monsoon shifting), there would be substantial global interest and basis for proceeding. In going forward, however, suggesting that the only cost would be to get the sulfate up there really omits the likely much larger cost of compensating the losers in some way. Not thinking about this and accounting for it is a bit like the fossil fuel industry at present, saying it is providing the least expensive energy while at the same time it is not counting the externalities. While all of these together might well provide a path through the 21st century that would not be overly costly and not unduly impose on future generations, it is a narrowing path with precarious footing, and if we don't get started immediately on all steps (some emphasizing implementation, some emphasizing research), having to run faster in the future seems sure to lead to some serious slips and bumps in the road--at least. Mike MacCracken On 5/11/11 12:10 PM, "Dr. Wil Burns" <[email protected]> wrote: > Hi Michael, > > Several responses here: > > 1. A future generation might have no choice in terminating an SRM > approach should it technologically fail; this is certainly not beyond > the pale. For example, various climatic feedback processes might > ultimately denude the effectiveness of cloud brightening or particle > dispersants in the stratosphere; > 2. A future generation might deem the use of such technologies > unethical should they be visiting grave harms on certain vulnerable > populations, such as the potential for substantially denuding > precipitation in southeast Asia. A nation in that region might also > threaten military retaliation, compelling suspension. The point is > that the consequences then would be potentially very grave in terms of > the termination effect; > 3. I find your view that it's this generation saving itself vs. the > needs of future generations excessively reductionist. There is a third > alternative, which is substantive measures by this generation to > reduce its greenhouse gas emissions. As the article points out, some > measures, e.g. massively reducing black carbon, might be able to > prevent us from crossing the critical thresholds that are often cited > as a rationale for geoengineering. I want those options explored in a > meaningful fashion before we are lured by the siren song of > technologies that pose a substantial moral hazard, and perhaps an > extremely palpable societal hazard should the termination effect be a > realistic consequence of SRM deployment. wil > > On May 10, 11:01 pm, Michael Hayes <[email protected]> wrote: >> Thanks for posting this link. This was a very interesting read. >> >> I read your contribution concerning intergenerational equity and have a >> question on one concept. I quote: >> >> "Unfortunately, while a commitment to SRM geoengineering approaches in lieu >> of >> effective mitigation responses might prove effective and politically >> palatable for our >> generation, future generations may not feel the same way because of the >> threat posed by >> the ³termination² effect." >> >> I need help in understanding what would motivate a future generation to >> discard an active SRM effort due to the threat of the effects of discarding >> an active SRM effort. From a philosophical stand point, such a future >> generation, with that view, would simple be collectively suicidal. As such, >> should we be constrained by their irrational views (suicide is >> mainly considered irrational)? Your definition of intergenerational equity >> states "fairness in the utilization of resources between human generations * >> past*, *present* and *future*.". We, today, will be the "*past*" generation >> to this hypothetical *future* suicidal generation. Thus, the question comes >> to mind, in that: Do they not owe us, as a "*past*" generation, fairness in >> the utilization of resources (ie. SRM) if SRM is deemed by us as crucial to >> our generations' survival? Do we not owe them our survival so that they may >> even come into existence? >> >> Is there a flaw in my logic? This issue does seem to me like Schrodinger's >> Cat is vigorously chasing a lifeless tail! >> >> I do need help in understand the rational nature of your argument. >> >> Thanks, -- 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.
