Science on the Risks of Climate Engineering: “Optimism about a geoengineered ‘easy way out’ should be tempered by examination of currently observed climate changes”

As the risks of climate change and the difficulty of effectively reducing greenhouse gas emissions become increasingly obvious, potential geoengineering solutions are widely discussed. For example, in a recent report, Blackstock et al. explore the feasibility, potential impact, and dangers of shortwave climate engineering, which aims to reduce the incoming solar radiation and thereby reduce climate warming. Proposed geoengineering solutions tend to be controversial among climate scientists and attract considerable media attention.  However, by focusing on limiting warming, the debate creates a false sense of certainty and downplays the impacts of geoengineering solutions.

So begins, “Risks of Climate Engineering” (subs. req’d), an important piece in Science this month by Gabriele Hegerl and Susan Solomon.  Hegerl was a coordinating lead author for the Fourth Assessment Report.  Solomon is an atmospheric chemist working for NOAA and “one of the first to propose CFCs as the cause of the Antarctic ozone hole.”

Solomon was lead author of the even more important February PNAS paper, “Irreversible climate change due to carbon dioxide emissions,” which, as I noted at the time, gives the lie to the notion that it is a moral choice not to do everything humanly possible to prevent this tragedy, a lie to the notion that we can “adapt” to climate change, unless by “adapt” you mean “force the next 50 generations to endure endless misery because we were too damn greedy to give up 0.1% of our GDP each year” (see NOAA stunner: Climate change “largely irreversible for 1000 years,” with permanent Dust Bowls in Southwest and around the globe).  No surprise, then, that she co-authored a paper skeptical of geoengineering.

I remain dubious of geo-engineering (see Geo-engineering remains a bad idea” and “Geo-Engineering is NOT the Answer” and British coal industry flack pushes geo-engineering “ploy” to give politicians “viable reason to do nothing” about global warming, which includes an excellent analysis by Prof. Alan Robock).  Science advisor John Holdren told me in April that he stands by his critique:

“The ‘geo-engineering’ approaches considered so far appear to be afflicted with some combination of high costs, low leverage, and a high likelihood of serious side effects.”

The new analysis by Hegerl and Solomon is sufficiently significant — Science itself featured it early in Science Express — that I’ll excerpt it below:

Discussions of “dangerous” levels of interference with the climate system often use warming as a proxy for the seriousness of greenhouse gas-induced climate change. However, climate change impacts are driven not only by temperature changes, but also by change in other aspects of the climate system, such as precipitation and climate extremes. If geoengineering studies focus too heavily on warming, critical risks associated with such possible “cures” will not be evaluated appropriately. Here, we present an example illustrative of the need for greater emphasis not only on possible benefits but also on the risks of geoengineering””in particular, the risks already suggested by observations of climate system change.

Carbon dioxide increases cause a reduction in outgoing longwave radiation, thus changing the heat balance of the planet. Several proposed geoengineering solutions aim to avoid the resulting energy imbalance that will lead to warming by reducing incoming solar radiation. This may be achieved by, for example, increasing the number of atmospheric reflecting particles in the stratosphere or by placing reflecting “mirrors” outside the atmosphere.

Kind of ironic that the two most widely discussed geo-engineering strategies are, literally, smoke and mirrors.

These measures are indeed expected to reduce the projected warming (1, 2). Blackstock et al. focus on this particular example of geoengineering, with the rationale that it may allow rapid action to be taken if a threat of catastrophic climate change emerges. Such emerging threats could, for example, be rapidly disintegrating ice sheets, or warming that is more rapid than expected (4). One of the attractions of shortwave climate engineering is the effectiveness and rapidity with which it could reduce warming, but it is also connected with considerable risks.

It is clear that reducing incoming shortwave radiation would lead to decreases in temperature. Volcanic eruptions in the 20th century led to substantial coolings that occurred within months after the eruption and lasted several years (5, 6). Strong volcanic eruptions have in the past led to anomalously cold conditions: The year without a summer (1816) noted in North America and Europe followed the eruption of Tambora in Indonesia the year before, which was the largest volcanic event observed in recent centuries (5). However, volcanic eruptions also affect precipitation (7). The 1991 eruption of Mount Pinatubo led to substantial decreases in global stream flow and to increases in the incidence of drought (see the figure) (8). An analysis of 20th-century observations indicates that volcanic eruptions caused detectable decreases in global land precipitation (9, 10). The reason is that with reduced incoming shortwave radiation and surface cooling, less energy is available for evaporation.

Greenhouse gas increases also influence precipitation, through two mechanisms: directly through reducing outgoing longwave radiation, and indirectly through warming (1113). Warming increases evaporation, thus making more water available globally for precipitation. However, because greenhouse gases reduce outgoing longwave radiation, they also reduce the effectiveness with which the atmosphere radiates out latent heat of condensation. This reduces precipitation. The net result of the two mechanisms is a relatively small increase in global precipitation in the early stages of greenhouse warming simulations (12).

That’s a nice, simple explanation of something I hadn’t seen elsewhere.

The 20th-century climate record shows the different effects of shortwave and longwave forcing on temperature and on precipitation. Global surface temperature responds in a quite straightforward way to changes in the energy budget, irrespective of whether shortwave or longwave radiation changes are involved. Thus, temperatures in the latter part of the 20th century were dominated by anthropogenic warming (interspersed with short-term cooling after volcanic eruptions) (14). In contrast, precipitation reacts more strongly to reductions in incoming shortwave radiation, such as volcanic eruptions or shortwave climate engineering, than to reductions in outgoing longwave radiation associated with greenhouse gas forcing…. Models have been able to capture the patterns of precipitation changes with greenhouse warming (14, 15) but appear to underestimate the magnitude of precipitation changes over the 20th century in response to both shortwave and longwave forcing…. Similarly, the observed global land precipitation response to volcanic forcing over the 20th century was much stronger than that simulated by present climate models (9, 10).

Satellite data also suggest that climate models underestimate the magnitude of forced changes and of variations in precipitation extremes (16, 17). Although these data are limited (13), they all suggest that precipitation changes are being underestimated. Missing external forcings (such as by absorbing aerosols) or errors in observations could contribute to the discrepancy between observations and model simulations. However, until these discrepancies are fully resolved, models cannot reliably predict how shortwave engineering can target precipitation and temperature simultaneously (18), implying that very large risks are associated with any such geoengineering scheme.

Some models suggest a large degree of cancellation between changes in warming and in precipitation in a shortwave climate-engineered world (18). However, models have been shown to have problems simulating past precipitation variability as well as trends. Furthermore, the combination of a strong greenhouse effect with a reduction of incoming radiation could have substantial effects on regional precipitation (19), including reductions that would rival those of past major droughts (20). Geoengineered changes in the environment could thus lead not only to “winners and losers” but even to conflicts over water resources (19) and the potential for migration and instability, making shortwave climate engineering internationally very controversial.

I see the liability issue as enormous.  Right now, we’re all liable for climate change, though obviously the rich countries are far more to blame.  But the bulk of the liability extends back many decades and involves many hundreds of millions of people and thousands of industries.  A major geo-engineering effort, however, would put all of the liability for any adverse impacts on those who undertake it.  The liability could be huge but the number of parties involved might be small if it proves impossible to get a global agreement to adopt that strategy. Yet if we fail to aggressively pursue mitigation, then the very countries who would likely be the leaders on geo-engineering are going to be global pariahs for having greedily refused to spend a modest amount of money needed to reduce emissions in the first place.  So if there were, say, a massive drought in India and Bangladesh in the few years after a geo-engineering effort a particulate-based effort began (the mirrors strategy seems likely to be too expensive and impractical), those behind the effort would bear tremendous responsibility.

Thus, from a purely practical perspective, a true geo-engineering strategy is going to be much tougher to pursue than is widely realized.  That goes double if we don’t keep emissions near what is required to stabilize below 450 ppm.

Blackstock et al. call for a study phase, during which the possible impacts of geoengineering options could be investigated. This is clearly necessary, and optimism about a geoengineered “easy way out” should be tempered by examination of currently observed climate changes. Climate change is about much more than temperature change, and using temperature alone as a proxy for its effects represents an inappropriate risk to the health of our society and to the planet.

Hear!  Hear!
  • 1. J. J. Blackstock et al., Climate Engineering Responses to Climate Emergencies (Novim, 2009), available at
  • 2. P. J. Crutzen, Clim. Change 77, 211 (2006). [CrossRef]
  • 3. A. Robock, Bull. At. Sci. 64, 14 (2008).
  • 4. G. A. Meehl et al., in Climate Change 2007: The Fourth Scientific Assessment, S. Solomon , Eds. (Cambridge Univ. Press, Cambridge, 2007), pp. 747-845.
  • 5. A. Robock, Rev. Geophys. 38, 191 (2000). [CrossRef]
  • 6. G. C. Hegerl et al., Geophys. Res. Lett. 30, 1242 (2003). [CrossRef]
  • 7. A. Robock, Y. Liu, J. Clim. 7, 44 (1994). [CrossRef]
  • 8. K. E. Trenberth, A. Dai, Geophys. Res. Lett. 34, L15702 (2007). [CrossRef]
  • 9. N. P. Gillett, A. J. Weaver, F. W. Zwiers, M. F. Wehner, Geophys. Res. Lett. 31, L12217 (2004). [CrossRef]
  • 10. F. H. Lambert, N. P. Gillett, D. A. Stone, C. Huntingford, Geophys. Res. Lett. 32, L18704 (2005). [CrossRef]
  • 11. J. F. B. Mitchell, C. A. Wilson, W. M. Cunnington, Q. J. R. Meteorol. Soc. 113, 293 (1987). [CrossRef]
  • 12. M. R. Allen, W. J. Ingram, Nature 419, 223 (2002).
  • 13. F. H. Lambert, A. R. Stine, N. Y. Krakauer, J. C. H. Chang, Eos 89, 193 (2008).
  • 14. G. C. Hegerl et al., in Climate Change 2007: The Fourth Scientific Assessment, S. Solomon , Eds. (Cambridge Univ. Press, Cambridge, 2007), pp. 663-745.
  • 15. X. Zhang et al., Nature 448, 461 (2007). [CrossRef] [Medline]
  • 16. F. J. Wentz, L. Ricciardulli, K. Hilburn, C. Mears, Science 317, 233; published online 30 May 2007.[Abstract/Free Full Text]
  • 17. R. P. Allan, B. J. Soden, Science 321, 1481; published online 7 August 2008.[Abstract/Free Full Text]
  • 18. K. Caldeira, L. Wood, Philos. Trans. R. Soc. London Ser. A 366, 4039 (2008).
  • 19. A. Robock, L. Oman, G. L. Stenchikov, J. Geophys. Res. 113, D16101 (2008). [CrossRef]
  • 20. G. T. Narisma, J. A. Foley, R. Licker, N. Ramankutty, Geophys. Res. Lett. 34, L06710 (2007). [CrossRef]

44 Responses to Science on the Risks of Climate Engineering: “Optimism about a geoengineered ‘easy way out’ should be tempered by examination of currently observed climate changes”

  1. Leif says:

    None of the above geo-engineering plans do anything about ocean acidification, a direct response of CO2 in the atmosphere. Ocean acidification effects the base of the food chain as well as coral reefs, anything with a shell, and thus supply the world with much of its protein. Certinally one of the protein sources with the lowest carbon and fresh water footprint.

  2. dan says:

    Agree – our ability to out think nature is pretty limited. We know that we must stop using coal and oil…that should really be the center of the discussion….

  3. David B. Benson says:

    Partial solutions include: (1) growing biomass to make biochar. The biochar is either burnt for process heat or else buried; (2) increased use of biodiesel made from non-food vegetable oils; (3) increased use of biomethane (as natural gas replacement) made from wet biomass wastes. Every village, town and city in the world ought to be doing (3), along with animal feedlots and slaughterhouses. For the first two the production is mostly limited to the Global South, as it is called.

    All are close to carbon neutral in that no fossil carbon is oxidized; burying biochar is actually carbon negative in that it removes carbon from the active carbon cycle (and so addresses ocean acidification).

  4. Geo-engineering is the ultimate in buck-passing, NIMBYism that only works to permit a few more cycles of hyper-carbonized self delusion. It is a religious penance allowing for carbon sin.

    The first step of any serious Geo-Engineering effort will be to stanch the flow of CO2 emissions. The best way to do that is by zero’ing out carbon emissions. This is so unrealistic as to make any geo-engineering effort a palliative solution at best – a dangerous gamble at worst.

    It is like the alcoholic taking vitamins in order regain health for a continuing binge. We cannot say such an action is incorrect, but it is really missing the point.

    Any individual can wake up and decide to face the future. Now, for the first time ever, all humans have to decide whether the species should survive. Much like any stressed, endangered individual might decide to fight the challenge.

    Fascinating, because the decision must be made soon and acted upon immediately. And anyone alive today can help decide and contribute to securing a future for humans. The only true unknown is whether it is already too late.

  5. Leif says:

    If memory severs me correct, biochar also improves the soil fertility. A big help in a hungry world.

  6. Phillip Huggan says:

    Those freons almost did us in. They were discovered lethal by fluke when a scientists figured they could be used as inert global atmospheric wind pattern markers. The chemical formula of CFC reactions in the air was known, but no one thought to look that the same molecule showed up in both sides of the equation; no one thought to make the equation recursive until almost too late.

    The assuming limited warming makes the same mistake as stimulus programmes that must be spent shortly (instead of diminishing the preference for early projects gradually). Assuming limited warming who cares about AGW?

    Listening to some geoengineering solutions reminds me of the final episode of Jim Henson’s “Dinosaurs” puppet sitcom. The industrialists change the climate a bit and progressively uncan a Pandora’s Box of solutions that wipes them out. Human extinction actors forwarding these as a distraction undoes much of the potential good geoengineering could accomplish.

  7. ecostew says:

    The cost of mitigating AGW is trivial compared with attempting to adapt (geo-engineering is clearly crap) to intensifying destruction of our society from intensifying AGW (e.g.,loosing energy, food, and water security) and destroying Earth’s ecosystems, and for what, corporate greed and US legislators wanting to be re-elected.

  8. ecostew says:

    Leif, Soil fertility/biochar sustainability systems have not been documented in peer-reviewed science.

  9. Leif says:

    ecostew, by googling “biochar soil fertility” the first site that came up is a Cornell University study with lots of footnotes. Perhaps my choice of words was misleading in it is a fact that biochar in and of it’s self is not a fertilizer however it does appear to assist in soil holding nutrients and water, thus assist in soil fertility and significantly improving productivity.

  10. This is a pretty mild critique of geo-engineering compared to what’s out there.[1] And I would agree that most proposed methods of geo-engineering are not worth it. But I must put in a word for air capture (concentration of atmospheric CO2 via air scrubbers) followed up with solid sequestration (in mineral carbonates, in buried plantation biochar). Unlike aerosol-based cooling, this is not just a partially compensatory countermeasure, this is the endgame: actually removing the excess carbon from the biological carbon cycle. Anyone interested should dig through RealClimate’s discussion of air capture.[2]



  11. paulm says:


    Peak Oil? Urban Farms? Cuba’s Been There, Done It
    The immediate results were said to be striking. Cubans got thinner. The UN Food and Agriculture Organization estimated the average person’s intake went from 2,600 calories a day in the late 1980s to between 1,000 and 1,500 in the 1990s.

    And yet, ten years after the Soviet collapse, food had become more plentiful. In 1999, the Cuban Association for Organic Agriculture won the International Right Livelihood Award (the alternative Nobel Prize). In 2006, Cuba was named by the World Wildlife Fund to be the only country in the world with sustainable development.

  12. Leland Palmer says:

    It seems inherently very difficult to take a situation suffering from numerous runaway positive feedbacks tending to make the system go out of control, and successfully bring the system back into control by adding still another factor.

    I don’t think it works that way. Certainly, we’re not that smart, to be able do this, I think.

    The climate system is being poisoned by the carbon released by the industrial revolution.

    To bring the system back into control, put the carbon back underground.

    We need to nationalize the coal fired power plants, and convert them to enhanced efficiency power plants that burn biomass or biochar, and deep inject their captured CO2. If we did this worldwide and immediately, we could transfer several billion tons of carbon per year from the biosphere to the ground.

    The climate system speaks the language of billions of tons of carbon.

    We need to start speaking that language to the climate system, ASAP.

    Geoengineering seems hopeless.

    The thing to do is put carbon back underground, and allow the system to return to equilibrium, IMO.

  13. ecostew says:

    I would proceed with caution using biochar as a soil amendment, for example:

  14. Lewis Cleverdon says:

    Leyland –

    you wrote :-
    “The thing to do is put carbon back underground, and allow the system to return to equilibrium, IMO.”
    This seems to me spot on. Yet a number of qualifications are needed, IMO.

    1/. The forthcoming “Treaty of the Atmospheric Commons” (to give it its proper title) will need to permit only a minor fraction of nations’ emissions cuts being offset by techniques such as Biochar sequestration, to avoid the wholesale offsetting of any advance being achieved.

    2/. The production of feedstock for Biochar manufacture has to be accredited as sustainable if it is not to exacerbate already chronic problems of farm-soil and native-forestry abuse, and, of course, it has to entirely avoid taking farmland out of food production (apart from agriculturally justified shelter-belts, tree-cropping, tree-alley cropping, hedgerows, etc).

    3/. The urgency of reducing CO2 ppmv is being multiplied by the acceleration of diverse interactive feedback loops, such that the question of the necessary scale of Biochar is not of how many gigatonnes/yr of it we need, but of how soon this option can be maximized within the constraints noted at 2/.

    The major proponents of Biochar started to discuss worldwide afforestation on degraded and non-farm land, seeing an output of between 5.0 and 9.0 GTC /yr from this along with extant biomass wastes. A small ultra-shrill enviro clique then attacked the idea viciously from of their assumption that productive forestry meant GMO-monoculture-inclosures destroying both old forest and farmland, whereupon the Biochar proponents withdrew to a quieter “wastes feedstock only” starting point, with a goal of a mere 1.0 GTC /yr.

    This well-meant appeasement seems to me sadly unproductive, in that the clique will continue their slander until they are seen off. They have, for instance, just blocked the inclusion of Biochar from the draft document for Copenhagen.

    The more effective approach is surely to promote the numerous benefits of sustainable afforestation for Biochar feedstock both in public discussion and in practical enterprises. To this end the choice of silviculture is critical.

    4/. The optimum silviculture for Biochar feedstock production is very probably the ancient art of Coppice, whereby the (native deciduous) trees are harvested on a cycle mostly of between 7 & 28 years (various factors dictate the period) and they are encouraged to regrow from the stump and its surviving root-ball, which they do vigorously about 20% faster than normal replanted cohort forestry.

    I’ve no firm data for the rest of the world, but in Europe native-species in-cycle Coppice supports the highest bio-diversity of any ecosystem.

    Among various other notable merits is the relatively early first harvest from this silviculture, being potentially as little as 7 years, as well as the fact that the stems are small enough to be easily cut with machetes (not costly chainsaws) and manually loaded to oxcarts for haulage to the local village wood-refinery . . .



  15. daniel smith says:

    what about klaus lackner’s machines that suck carbon directly out of the air? i assume he’s a ways from having his technology ready and cost-effective, but certainly he’s no dummy, and i believe wally broeker is a believer. but i haven’t seen any thoughtful comment on this, or really even much press coverage. is there anything there, or is it just another lovely idea that will never come to pass?

    [JR: That’s not GEO-E in my book. It’s just another method for getting CO2 out of the air, like, say, biomass power or planting trees. The question then is whether it is cheaper, more practical, and more scalable than other strategies, including mitigation. So far, not even close.]

  16. ecostew says:

    More on biochar – the science is not settled:

  17. Leif says:

    Being a retired shipwright, I will readily admit that I do not understand all I know about biochar or many other things for that mater. However geo-engineering is certainly accomplishable as are current CO2 predicament testifies. The question now appears to be weather or not mankind will acknowledge our roll and work toward the well-being of the planet and humanity or do we boil the frog.
    Capitalism for all it’s faults appears to be a strong motivator, it just needs to be structured for the well-being of humanity and all and not just to make a few more billionaires on the backs of the poor…
    There would appear to be many job oppertunities out there sorting all this out however. A note to you unemployed.

  18. john says:

    Leif’s first comment is spot-on. At the end of the day, ocean acidification is a threat that is fully equivalent to atmospheric warming. While rainfall patterns and culpability are issues we should be concerned about, ocean acidification can actually effect some very serious things — like oxygen content of the atmosphere and food stocks for more than a billion people. I’m against geo-engineering on principle — as a former geologist, I see the interplay between the biosphere and the geosphere as extraordinarily complex, yet exquisitely delicate. We would lumber through this edifice like an elephant in a china shop.

    But even if its done as a contingency, no geo-engineering system which does not simultaneously address ocean acidification and warming should even be considered.

  19. daniel smith says:

    To follow up on the question fo Lackner and his carbon-sucking machines: Thanks for your reply, but could you offer more than your statement above that it is “so far, not even close.” To my knowledge, that is true for all geo-engineering proposals, but this seems to me something like saying that the fire insurance on my house is, so far, not even close to paying off.

    [JR: Fire insurance is a guaranteed payout — except of course for intentional self-inflicted arson, so that is, ironically, a good analogy. Our house is on fire and we set it.]

    I believe you frequently make the point that we run a very real risk of NOT mitigating, at least not effectively or sufficiently. So if we don’t mitigate (or if we do and the positive feedbacks get us anyway) and we move decisively towards your oft-mentioned “hell and high water”…what then? What do you (or others here) see as the potential of such schemes under a worst-case, or even just bad-case, scenario? To my knowledge, Lackner’s work is the only idea of this sort (to me sounds like geo-engineering, but whatever you want to call it) that does not carry the sorts of ecological or climatic risks discussed in this post. Does that perhaps give it a leg up, or is it just impractical technically? Many thanks, DS

    [JR: Nothing wrong in pursuing carbon capture. There is something wrong in thinking it’ll ever be practical and affordable at scale and not aggressively pursuing mitigation that we know is practical and affordable at scale now.]

  20. ecostew says:

    Indeed, ocean acidification is a huge issue:

  21. David B. Benson says:

    ecostew (15) — You posted that previously. Solution, obviously, is not to apply biochar in northern Swedish forests as a soil amendment.

    Use biochar where it clearly helps, as in the tropics.

    Otherwise compact it (like coal) and bury it deep (like coal); it’ll last a long time (like coal).

  22. Leland Palmer says:

    Hi all-

    I still think that carbon negative production of electricity, combining biomass or biochar fuel sources with carbon capture and storage is the only feasible and benign geoengineering option.

    But, we’re going to have to do something about the methane plumes rising into the ocean from the methane hydrates, too:

    The warming of an Arctic current over the last 30 years has triggered the release of methane, a potent greenhouse gas, from methane hydrate stored in the sediment beneath the seabed.

    Scientists at the National Oceanography Centre Southampton working in collaboration with researchers from the University of Birmingham, Royal Holloway London and IFM-Geomar in Germany have found that more than 250 plumes of bubbles of methane gas are rising from the seabed of the West Spitsbergen continental margin in the Arctic, in a depth range of 150 to 400 metres.

    These are going to increase, IMO, and likely cause significant ocean acidification and eventual release of methane to the atmosphere. Methane has a greenhouse impact 70 or so times that of CO2 when measured on a timescale of 20 years, and 25 times that of CO2 when measured on a timescale of 100 years.

    The U.S. and Japanese have patents, freely available on Google patents, which show plans to harvest methane hydrates for power using a collection hood made of flexible material, with weights on the edges, with the methane going up a flexible hose or pipe to a support ship.

    What I propose is to collect the methane from these plumes, as much as possible, and burn it via oxyfuel combustion in power generation support ships, then deep inject the resulting CO2 into basalt strata below the ocean floor. This would be a carbon neutral and probably economically profitable solution to at least part of this problem.

    I suggest building an underwater smart-grid, with electrical connections on bouys, so that these generator ships can relocate to new locations to harvest these plumes of methane, burn the methane via oxyfuel combustion, and deep inject the resulting CO2.

    Liquid (supercritical) CO2 could be transported by pipeline or ship from the generator ships to deep injection wells.

    Alternately, the methane could be compressed and brought to shore as liquid natural gas by ship, and burned conventionally.

    All of this would be expensive but self-supporting due to the value of the electricity or LNG sold.

    If we’re going to have a prayer of success in this battle against runaway global warming, we’re going to have to do something about these methane plumes.

  23. David B. Benson says:

    Leland Palmer (21) — Your biochar idea is fine but there almost surely is not enough photochemical potential to completely replace currrent fossil carbon use; we will need wind and solar as well.

    As for methane, the additional amounts being released into the atmosphere from permamelt (used to be permafrost) and clathrates is currently dwarfed by anthropogenic sources such as cattle belches. These antropogenic sources are likely to be much easier to control and some minor progress has already been made.

  24. Leland Palmer says:

    Hi David-

    Oh, yeah, we need a massive switch to wind and solar and any other relatively carbon neutral energy technologies, as you say. But we also need, desperately IMO, to go to carbon negative strategies like biomass/sequestration, and start putting carbon back underground.

    ORNL says that there is enough biomass:

    II. Resource and Usage Statistics

    1. How much biomass exists right now?

    Worldwide, total “standing crop” biomass (99% on land, and 80% in trees) is a huge resource, equivalent to about 60 years of world energy use in the year 2000 (1250 billion metric tonnes of dry plant matter, containing 560 billion tonnes of carbon). For the U.S. alone, standing vegetation has been variously estimated at between 65 and 90 billion tonnes of dry matter (30-40 billion tonnes of carbon), equivalent to 14-19 years of current U.S. primary energy use. However, the Earth actually grows every year about 130 billion tonnes of biomass on land (60 billion tonnes of carbon) and a further 100 billion tonnes in the rivers, lakes and oceans (46 billion tonnes carbon). The energy content of this annual biomass production is estimated to be more than 6 times world energy use or 2,640 exajoules (2500 Quads) on land, with an additional 2024 exajoules (1920 Quads) in the waters.

    There’s lots of biomass, but there are a few problems:

    Biomass is heavy, full of water and hard to transport.

    And when standing, it is taking CO2 out of the air, and storing carbon in a form (trees) that was once stable, but is starting to become unstable, due to wildfire growth.

    The transport problems could be solved by gravity assisted transport via rivers and streams, conversion of biomass to biochar, and transport of biomass as pyrolysis gas or carbon monoxide, as well as all conventional transport options. Reduction in water content could be done as part of pyrolysis, or via solar assisted drying.

    Forests go through a carbon cycle, in which young forests take up large amounts of carbon, and older forests mostly just store it. Also, there is a lot of waste biomass, which could be carbonized into biochar, and some of it incorporated into the soil as a soil additive while some is exported to the converted carbon negative power plants.

    The anthropogenic sources of methane are bigger than these hydrate belches, I think- right now.

    I don’t think that will last, unfortunately- as the waters warm, these hydrate plumes are going to get more and more common, likely, and could grow to really huge proportions, injecting methane directly into the atmosphere.

    We need to start building the infrastructure to engage in carbon neutral remediation of these hydrate plumes, ASAP, to limit ocean acidification if for no other reason. And it’s a huge source of energy, which can be made carbon neutral, and displace conventional fossil fuel use.

  25. Omega Centuri says:

    D Benson @22, thanks. People are getting carried away with the permamelt stuff. It is really just a minor feedback,slightly increasing the climate sensitivity.

    I think we need to classify several types of geo-engineering.
    The least controversial ones,with bio-char enthusiasts being the most vocal. It is also feasible to bust up silicate rocks and increase the production of carbonates with silicate to carbonate weathering. More controversial would be ocean fertilization. I suspect some small carbon reduction wedges to become available due to these types of efforts. Counting on them being sufficiently strong to counteract BAU emissions would of course be folly.

    Sulphate injection is deservedly controversial, for short wave forcing, but it is reversible -just quit doing it. Some minor local albedo interventions, such as white roofs, and more reflective paving materials make sense for mitigating the local urban heat island effect, but are too small to significantly offset greenhouse gas forcings. At least this later type should be encouraged to go ahead , as its primary global influence would be via local reduction on air conditioning demand.

  26. Harrier says:

    Leland, would it be possible to focus on drawing CO2 out of the atmosphere to sufficient levels- say, below 300 ppm- and then maintain the withdrawal infrastructure as more methane leaks out? Methane eventually breaks down into CO2, after all, at which point it too would be removed from the atmosphere by your biocarbon plan and other similar ideas.

  27. Leland Palmer says:

    Oh, this is off topic, but a little funny.

    I’ve just been kicked off of Watts Up With That, apparently, even though I was unfailingly polite, and tried to stay within the rules.

    Apparently, I was in danger of actually making some of the people that frequent that site actually think.

    If this comes up on another thread, I’ll share my experience of trying to talk sense to people on Watts Up With That, and the tactics that the management uses over there to suppress information from actually getting to WUWT readers.

  28. Leland Palmer says:

    Oh, Hi Harrier-

    Carbon negative energy production has not been studied as much as it should have, IMO. Google Read and Lermit, the website biopact (now sadly defunct) and the Russian/Norwegian Bellona foundation, and you will have found most of the web resources on this idea.

    People have tended to reject the idea as “too good to be true” or “something for nothing” which is not the case – it’s just about switching carbon sources, so that the ultimate source of carbon used to produce power is the biosphere (and so the atmosphere), and the ultimate destination of the carbon is deep injection in the earth or sequestration as a carbonate.

    I think it is possible to do what you suggest. If we can get CO2 back down below 350 ppm, most of the potential for a real runaway methane catastrophe would be reduced. So if we could get CO2 down to 350 ppm or below, and maintain it there, while engaging in as much carbon neutral methane hydrate remediation as possible, we have a shot at preventing a methane catastrophe, I think.

    We have all the scientific and technological tools necessary to do this, I think.

    But I despair at the momentum of the climate.

    We really need to start putting as much carbon back underground as our technology is capable of, get CO2 levels down, and hope that the climate system is as confused at the sudden spiking of CO2 levels as we are, sees it as a blip, and goes back to regulating itself.

  29. Leland Palmer says:

    Hi Lewis Cleverdon-

    Very interesting post, many interesting ideas. Coppice? Very interesting.

    The comments about the “small vicious enviro clique” agree with my own perception of what occurred, and I have sometimes wondered about the funding of that clique. I think that there’s likely a story there, which may never be told, unless some enterprising reporter or blogger takes the time to look into it.

    Interestingly enough, some of the discouraging information about biomass and the feasibility of carbon neutral energy sources comes from Standford University, which receives a lot of funding for some of their programs from ExxonMobil.

  30. john says:


    To dismiss methane releases from hydrates and permafrost as “minor so far” is a lot like the guy who fell from the Empire State Building, who screamed as he plummetted past the 20th floor, “everything’s OK, so far.”

    Look, there’s no off switch for this stuff — the volumes are huge (exceeding all known reserves) — and if we don’t act, they will (unless they already have) start a self-reinforcing feedback loop the way they did in the PETM and the Permian Die-off.

  31. Leland Palmer says:

    Oh, on edit-

    Typo alert! It’s Stanford University, of course.

    Here’s a link to the ExxonMobil funding of GCEP, the Global Climate and Energy Project.

    Some really devastatingly discouraging evaluation of biomass as an energy source has come from that project.

  32. Wilma says:

    ‘Angels Don’t Play This HAARP’–is any one familiar with this book?

  33. Cynodont says:

    Hey Joe,

    You’ve got the frame all wrong. Geoengineering is the “easy way out”. It’s the “only way out”. We’re not going to stop catastrophic runaway climate change without a combination of deep and rapid cuts in emissions concurrent with a suite of geoengineering techniques properly applied to minimize risk.

    There are a number of amplifying feedbacks between human and natural CO2 emissions that threated to rapidly overwhelm current human CO2 emissions. For example, the Arctic permafrost has roughly 1,600 GtC of organic frozen carbon, which will be inexorably released to the atmosphere if we don’t save the Arctic Sea ice. Geoengineering is likely the only way we can save it now. Also, note that 1,600 GtC will create warming equivalent to well over 100 times the historical total of human CO2 emissions. Do the math yourself.

    Rather than always lobbing bombs at geoengineering, why not get busy on helping the world figure out an effective risk-management framework for geoengineering? If you truly understand the threats of non-linear runaway CO2 feedbacks, you would have no choice but to grudgingly accept geoengineering as a necessary component to actually preventing climate catastrophe.

    [JR: And why don’t I get busy on helping the world figured out how to build a time machine and develop a framework for its use? I focus on the real, known solutions.

    We already have more people pushing geo-engineering and working on it then we need right now. If we don’t get on the sustainable path within next few years, we render all of the geo-engineering ideas moot.]

  34. David B. Benson says:

    Leland Palmer — Alas, it seems that humans already use around 24% of net land-based primary production.
    Even that is not sustainable without additional clean water sources. So to grow lots of biomass for carbon negative burning of resulting biochar will require very substantial “new lands” projects. I’ve previously suggested using the entire Sahara Desert; the pyrolysis oils are used for pumping seawater (and, to the extent necessary, desalination). Let’s see, Sehara is 7 million km^2 in area, which is 0.7 gigahectares which should be able to grow enough to make around 0.35 gigatonnes of biochar per year. Compare to U.S. consumption of about 1 gigatonne of coal per year.

    As for the methane releases from permamud and clathrates, note that interglacial 2, the Eemian, was about 1+ K warmer than now. Some slight evidence suggests that interglacial 4 was more like 3 K warmer than now. The difference now is black carbon, accelerating snow and ice melt; for removing the black carbon technical solutions exist and just need to be widely implemented.

  35. David B. Benson says:

    Phooey, I made a decimal point error in comment #34: … enough to make about 3.5 gigatonnes of biochar per year. (That’s about the same as the mass of coal burned each in in PRC+USA,)

  36. Leland Palmer says:

    Hi David B. Benson-

    Alas, it seems that humans already use around 24% of net land-based primary production.

    Yes, but use it how? For what? And where does the biomass waste end up?

    I’ll read your link with interest, but there’s no reason that human biomass use, has to be single use, I think. It’s been single use in the past, mostly, but doesn’t have to be so in the future, IMO.

    If for example corn is being grown, the stalks and so on are called corn stover, and are considered as waste, and are generally burned, or returned to the land. There’s no reason that the corn stover could not be turned into biochar, with half of it returned to the land and half of it sent off to the nearest carbon negative power plant, burned there, and the ash from that burning returned to the land.

    ORNL located 1.2 billion tons of agricultural and forest waste in their “billion ton vision” biomass report- under sustainable conditions. What with the beetle killed tree epidemic, I’m afraid that we have huge tracts of dead trees, containing hundreds of millions of tons of carbon, which will likely burn in wildfires unless this dead wood is harvested.

    It’s a massive husbandry, forest management, and replanting job, granted. Trees could perhaps be planted from airplanes, via aerial bombardment, as has been done before, planting hundreds of thousands of trees per day from airplanes.

    About the methane hydrates, the earlier warm periods likely happened slower, with much slower evolution of methane from the hydrates, and most of them remaining stable, likely. So there was time, for the methane to oxidize into CO2, and the CO2 to be sequestered naturally by rock weathering as carbonates. The difference now is that we have added 300 billion tons of carbon to the system from fossil fuels and have done so geologically instantaneously. Diatoms don’t have time to evolve, forests are burning or dying from insect epidemics, rather than advancing or retreating over thousands of years.

    So, we could be in for the mother of all methane catastrophes. We don’t know. But to prevent ocean acidification, we need to do something about the methane plumes from the hydrates, IMO.

  37. Leland Palmer says:

    Oh, on edit-

    Lest there be doubts, that’s 1.2 billion tons of biomass per year that ORNL located, rather easily, in the U.S., using conservative assumptions, most of it from agricultural waste.

    And, of course, there are the sad beetle killed trees, that we have to do something with, IMO. Even if they don’t burn, they will decay, and a lot of that standing carbon will end up in the air as CO2, from the decay process.

  38. Cynodont says:

    Why not run your time machine forward and elevate your geoengineering policy discussion to 2009? Most of your policy analysis on climate change solutions is excellent, but your analysis of geoengineering is several years out of date. Your considerable influence on policy makers would be very helpful in solving the liability issues that you correctly identified.

    It is abundantly clear that the world is charging past a climate tipping point of enormous proportions. We’re not getting out of this mess without a combination of dramatic emission reductions, sustainable development, AND geoengineering to buy time before tipping points overwhelm whatever reductions human society manages in the next 20 years.

    I think your policy analysis of geoengineering needs a more balanced approach to reflect that geoengineering is a risk-risk tradeoff that needs the full engagement of academia and public policy to figure an appropriate level of use.

    [JR: I think you miss the point on geo-engineering. My analysis is very current — hence the focus on what leading experts and scientific studies actually say. In fact, if you talk to scientists on this, as I have, and read the literature, as I have, then you’d know geo-engineering has precious little chance of doing bloody much without massive mitigation. Like I said, geo-engineering is getting all the attention it needs — and more than it deserves.]

  39. Wilma says:

    Hey Cynodont,
    What’s up with the techno-fix mumbo jumbo? Apparently, you’re a member of “the big boys with the big toys”.

  40. David B. Benson says:

    Leland Palmer — Ok, 1.2 billion short tons per year. Optimistically assuming that is 50% carbon and all is suitable for pyrolysis, that will make around 0.3 billion short tons of biochar per year, replacing almost 25% of the coal burned each year in the USA alone.

    Not a shabby start, but a long way from enough.

  41. Leland Palmer says:

    Hi David B. Benson-

    For the U.S. alone, standing vegetation has been variously estimated at between 65 and 90 billion tonnes of dry matter (30-40 billion tonnes of carbon), equivalent to 14-19 years of current U.S. primary energy use.

    We’ve got 30-40 billion tons of standing carbon in the U.S. The ORNL estimate was based on existing biomass stocks, with no additional biomass plantations planted, and postulated a sustainable, rather than an emergency harvesting operaton.

    We’ve got 5-6 million acres of beetle killed trees alone, which probably contain something like 200 million tons of carbon, right there.

    Consider that 300 million tons of carbon, from the ORNL billion ton vision report, though.

    If it is burned in carbon negative power plants, that combine biochar with sequestration, that would mean 300 million tons of carbon put back into the ground. This would displace the combustion of at least 300 million tons of coal.

    But that would mean that we could also burn natural gas containing 300 million tons of carbon, equivalent in heating value to maybe 500 million tons of coal, to get back to carbon neutrality.

    If we harvest the forests in a way that would limit wildfires, for example by cutting firebreaks through the forest and clearing the forests of beetle killed trees and combustible undergrowth, we could prevent maybe another 100 million tons of carbon from entering the air from wildfires.

    If we use the electricity to run electric cars, this could prevent perhaps another 200 million tons of carbon from entering the air.

    Carbonization of biomass would also be a great way to keep organic material like garbage or manure from decaying and producing methane. We could get tens or even hundreds of millions of tons of CO2 equivalent just from prevention of methane producing decay, IMO.

    So, from our 300 million tons of carbon put back in the ground, we could get maybe a billion tons of “swing” (change in the amount of carbon emitted to the atmosphere.

    Then, there’s always imports. British Columbia has 35 million acres of beetle killed trees, with maybe a billion tons of carbon content in them. Biochar log pipelines could be constructed, to carry compressed biochar logs probably thousands of miles before pumping energy exceeds the energy in the biochar logs. Tropical forests are also going to burn, unless we fire protect them, and Central American countries might very well be willing to sell us shiploads of biochar.

    Most coal fired power plants are on rivers, for cooling water. All of the territory upstream of the coal plant, the entire watershed at a higher elevation than the coal fired power plant, then becomes potential biomass collection or biomass plantation area.

    We need to put a billion tons of carbon back into the ground, here in the U.S.

    We have the coal fired power plants to do it, the carbon sequestration technology to do it, and the natural and artificial transport network necessary to do this.

    The only thing we have in short supply is political will, a shortage of truth, IMO.

  42. Leland Palmer says:

    On edit-

    Most of the sentences in the above post should say “per year”.

    We have the technology to put a billion tons of carbon per year back in the ground, here in the U.S. Worldwide, using biomass/sequestration, we could put several billion tons of carbon back into the ground, and solve this runaway global warming problem, even artificially moving us back past the climate tipping point to safety.

    I think we can find or grow sufficient biomass to do this.

    We need to nationalize the coal fired power plants, and convert them into enhanced efficiency carbon negative power plants, that run on biomass or biochar, that combine oxyfuel combustion with a topping cycle, and that capture their CO2 for deep injection.

    We need to deep inject the CO2 into fractured basalt layers, and deep saline aquifers, which have billions of tons of carbon storage potential. Most U.S. coal fired power plants sit directly on top of such deep saline aquifers, for example.

    Most U.S. coal fired power plants are located on rivers, often navigable rivers in the Mississippi/Ohio river basin. Such rivers constitute a natural transportation network to get the biochar or biomass to the converted coal fired power plants.

    We need to do this on an emergency basis, and not have to fool around trying to persuade the coal fired power plant owners to make incremental changes over decades. We need to just seize the power plants and do what needs to be done ASAP.

    We have a truth shortage, IMO, due to industry supported academic astroturfing, industry supported political efforts, and general industry supported lying to protect profits.

    We also have a shortage of political will to make the changes necessary to turn this problem around.

    It’s a solvable problem, IMO, we’re just not solving it, right now.

    We’re making climate progress, under Obama, but that progress is probably too slow.

  43. David B. Benson says:

    Leland Palmer — Decision makers have to be convinced, not me. One possible route is to present your ideas in e-mail to Sierra Club, UCS, etc.

  44. Leland Palmer says:

    Hi David-

    Yes, it’s true.

    But decision makers do apparently read Climate Progress.

    Once ideas get out into the network, they tend to percolate, and after a couple of exposures, they don’t look quite so ridiculous, hopefully.

    I hope that carbon negative energy ideas soon graduate from outlandish to “I knew it all along” and we can start putting some carbon back underground.