A couple of technology survey articles came to my attention in the last day or so, both of which are well worth the time of any TCOE (ir)regular.

The first is Review of solutions to global warming, air pollution, and energy security by Mark Jacobson (emphasis added):

This paper reviews and ranks major proposed energy-related solutions to global warming, air pollution mortality, and energy security while considering other impacts of the proposed solutions, such as on water supply, land use, wildlife, resource availability, thermal pollution, water chemical pollution, nuclear proliferation, and undernutrition. Nine electric power sources and two liquid fuel options are considered. The electricity sources include solar-photovoltaics (PV), concentrated solar power (CSP), wind, geothermal, hydroelectric, wave, tidal, nuclear, and coal with carbon capture and storage (CCS) technology. The liquid fuel options include corn-ethanol (E85) and cellulosic-E85. To place the electric and liquid fuel sources on an equal footing, we examine their comparative abilities to address the problems mentioned by powering new-technology vehicles, including battery-electric vehicles (BEVs), hydrogen fuel cell vehicles (HFCVs), and flex-fuel vehicles run on E85. Twelve combinations of energy source-vehicle type are considered. Upon ranking and weighting each combination with respect to each of 11 impact categories, four clear divisions of ranking, or tiers, emerge. Tier 1 (highest-ranked) includes wind-BEVs and wind-HFCVs. Tier 2 includes CSP-BEVs, geothermal-BEVs, PV-BEVs, tidal-BEVs, and wave-BEVs. Tier 3 includes hydro-BEVs, nuclear-BEVs, and CCS-BEVs. Tier 4 includes corn- and cellulosic-E85. Wind-BEVs ranked first in seven out of 11 categories, including the two most important, mortality and climate damage reduction. Although HFCVs are much less efficient than BEVs, wind-HFCVs are still very clean and were ranked second among all combinations. Tier 2 options provide significant benefits and are recommended. Tier 3 options are less desirable. However, hydroelectricity, which was ranked ahead of coal-CCS and nuclear with respect to climate and health, is an excellent load balancer, thus recommended. The Tier 4 combinations (cellulosic- and corn-E85) were ranked lowest overall and with respect to climate, air pollution, land use, wildlife damage, and chemical waste. Cellulosic-E85 ranked lower than corn-E85 overall, primarily due to its potentially larger land footprint based on new data and its higher upstream air pollution emissions than corn-E85. Whereas cellulosic-E85 may cause the greatest average human mortality, nuclear-BEVs cause the greatest upper-limit mortality risk due to the expansion of plutonium separation and uranium enrichment in nuclear energy facilities worldwide. Wind-BEVs and CSP-BEVs cause the least mortality. The footprint area of wind-BEVs is 2–6 orders of magnitude less than that of any other option. Because of their low footprint and pollution, wind-BEVs cause the least wildlife loss. The largest consumer of water is corn-E85. The smallest are wind-, tidal-, and wave-BEVs. The US could theoretically replace all 2007 onroad vehicles with BEVs powered by 73000–144000 5 MW wind turbines, less than the 300000 airplanes the US produced during World War II, reducing US CO2 by 32.5–32.7% and nearly eliminating 15000/yr vehicle-related air pollution deaths in 2020. In sum, use of wind, CSP, geothermal, tidal, PV, wave, and hydro to provide electricity for BEVs and HFCVs and, by extension, electricity for the residential, industrial, and commercial sectors, will result in the most benefit among the options considered. The combination of these technologies should be advanced as a solution to global warming, air pollution, and energy security. Coal-CCS and nuclear offer less benefit thus represent an opportunity cost loss, and the biofuel options provide no certain benefit and the greatest negative impacts.

The key detail everyone wants to see, the set of CO2 intensity numbers, is in table 3. I don’t think anything there will be too great a surprise to the informed reader, but if I’m wrong in that assessment, you can tell me.

If this were “all” this article covered, it would be a worthwhile read, but Jacobson also covers things like water consumption by the various electricity generation options (section 7), as well as how these technologies impact the environment when used to power battery electric vehicles.

The other article, and the one that triggered a sigh of resignation from me, is The radiative forcing potential of different climate geoengineering options, by T. M. Lenton and N. E. Vaughan:

Climate geoengineering proposals seek to rectify the Earth’s current radiative imbalance, either by reducing the absorption of incoming solar (shortwave) radiation, or by removing CO2 from the atmosphere and transferring it to long-lived reservoirs, thus increasing outgoing longwave radiation. A fundamental criterion for evaluating geoengineering options is their climate cooling effectiveness, which we quantify here in terms of radiative forcing potential. We use a simple analytical approach, based on the global energy balance and pulse response functions for the decay of CO2 perturbations. This aids transparency compared to calculations with complex numerical models, but is not intended to be definitive. Already it reveals some significant errors in existing calculations, and it allows us to compare the relative effectiveness of a range of proposals. By 2050, only stratospheric aerosol injections or sunshades in space have the potential to cool the climate back toward its pre-industrial state, but some land carbon cycle geoengineering options are of comparable magnitude to mitigation “wedges”. Strong mitigation, i.e. large reductions in CO2 emissions, combined with global-scale air capture and storage, afforestation, and bio-char production, i.e. enhanced CO2 sinks, might be able to bring CO2 back to its pre-industrial level by 2100, thus removing the need for other geoengineering. Alternatively, strong mitigation stabilising CO2 at 500 ppm, combined with geoengineered increases in the albedo of marine stratiform clouds, grasslands, croplands and human settlements might achieve a patchy cancellation of radiative forcing. Ocean fertilisation options are only worthwhile if sustained on a millennial timescale and phosphorus addition probably has greater long-term potential than iron or nitrogen fertilisation. Enhancing ocean upwelling or downwelling have trivial effects on any meaningful timescale. Our approach provides a common framework for the evaluation of climate geoengineering proposals, and our results should help inform the prioritisation of further research into them.

The reason for my melodramatic sigh is probably all too clear to longtime readers: I detest the idea of humanity having no choice but to make one or more of these geoengineering schemes work to save ourselves from the worst effects of climate chaos, but I’m convinced we’ve backed ourselves into exactly that situation.

Part of this mess was caused by pure happenstance–we emitted an astounding amount of CO2 into the atmosphere before even scientists were widely aware of the implications of our collective actions. Add to that unfortunate timing the decades lost as we turned the whole subject of what to do about climate chaos into a political football[1], and here we sit, locked into decades of additional climate change even if all man made CO2 emissions stopped today, even though we’re pumping out another 25+ billion metric tons of CO2 every year. We’re already seeing widespread effects from our past actions, and I honestly don’t see a scenario in which we’ll be able to avoid resorting to several geoengineering technologies.

Perhaps it’s my long history of reading (and even writing) science fiction cautionary tales, but I think anyone should be terrified that we’ll have to bet so much human suffering on our rookie attempt at low-level terraforming. This isn’t like trying to turn Mars into Earth 2.0[2], where we could at least keep living here, on Earth 1.0, if we screw it up; this is playing for some truly mind boggling stakes.

Overall, I think it’s critical that we pay a great deal of attention to technology survey articles like these two examples. We’re going to be facing a host of very important, very expensive in the coming years and decades, so we need to lay the groundwork for those decisions now.

[1] See Eric Pooley’s outstanding media critique and his discussion in passing of the Bush Administration’s serial sins in this area, as I mentioned the other day in Must-read dispatch from the infowar front. For the latest drivel salvo from the denier camp, see this example.

[2] Any thought of terraforming Mars compels me to plug the work of one of my writing instructors at the Clarion Writer’s Workshop, Kim Stanley Robinson, and his Red Mars, Green Mars, Blue Mars trilogy.