In keeping with my goal to permit a diversity of views to be posted on my weblog by published climate scientists, below is a post by Len Ornstein.
Guest Weblog By Len Ornstein titled “How to Quickly Lower Climate Risks, at ‘Tolerable’ Costs?”
The data on climate change are very noisy. The physics of hydrodynamic systems like the oceans and atmosphere behave somewhat ‘erratically’ and ‘chaotically’, (especially in comparison, for example, to the physics of the ‘predictability’ of the Earth’s orbit around the sun) and in addition, the choices that are made about how to collect climate data, also can be subject to some uncertainty and error. So it’s not surprising that attempts to discern ‘trends’ in climate data are subject to a good deal of uncertainty. This is characteristic of all scientific data; only it’s especially severe in climate science.
Scientist construct models of the world and then they (or others) observe the behavior of relevant, discrete, worldly events to test whether the models are useful for ‘prediction’ of future events and/or interpolation of unobserved ‘past events’ in between already observed events. In general, the larger the number of ‘pertinent’ observations, and the more similar are the ‘results’ to one another, the more ‘likely’ it is that calculated means (or trends of means), are representative of ‘reality’. Likewise, the closer a model prediction comes to such a measured trend, the more robust may be its ability to ‘predict’. To communicate how likely reality has been estimated by the measurements and by the model, science tries to cope with likelihood by using ‘agreed upon’ metrics of uncertainty – such as confidence intervals – to help make discussion of uncertainty more tractable. But the public is used to ‘statements of fact’, and mistrust the weasel words of confidence intervals; most haven’t yet learned that nothing that can be said about real world ‘facts’ is either absolutely certain – or absolutely false.
So when some scientist suggests that the mean of a ‘calculated trend’ of some kind of climate ‘feature’ (e.g., global mean surface temperature (GMST)) is biased on the high side because of measurement errors of a particular kind – and another says that the trend is underestimated for perhaps just the opposite reasons – the public often sees it as an ideological difference (which it sometimes may be!). But more commonly, it’s an honest difference of opinion that stems from the different data histories with which these scientists have experience. Both respect the general significance of the confidence interval around the mean of the trend. But because they differ on what they consider pertinent, one may favor the data closer to the bottom of the confidence interval – and the other, closer to the top.
On a small number of issues, I differ with Roger. His experience and mine differ widely, and I expect we can each learn from one another. His comments on the following matters will be appreciated:
The very wide 90% confidence interval of the GMST trend, includes as little as 1.5ºC/century. But even that would be an only slightly delayed “unmitigated catastrophe” – with business as usual. This is something that I conjecture Roger also believes. Obviously different aspects of ‘catastrophe’ cut in on different time scales, and can be ‘mitigated’ to different degrees. Those who are wealthy enough, can keep comfortable for some time, with air conditioning. But for most sea creatures dependent for survival on the stability of the aragonite (a form of calcium carbonate) in their ‘shells’ (snails, clams, corals, foramenifera, etc.), a drop of sea surface water pH of about 0.4 units (expected as a result of a doubling of atmospheric CO2) will be a catastrophe – whether beginning either 50 yrs, or 200 yrs from now! Cooling by geo-engineering – without decarbonation – can’t save them.
That’s a good example of why uncertainty is not an excuse for inaction.
Roger recently posed the following question and answer on his thread,
“9. What do you think are the most important long-term external risks that players in the global energy game have under-attended to?
His answer: The exclusion of energy sources, such as coal before there are adequate replacements, risks serious economic and social upheaval.”
I’m one of those who is certain that we must stop burning coal as soon as possible. (Roger Jr’s recent ‘kudos’ to Greenpeace shows he also shares this opinion.) And I believe that can begin much sooner than most believe – without risks of “serious economic and social upheaval”.
I have 2 papers in press at the journal, Climatic Change, that are already available online:
Ornstein L, Aleinov I and Rind D , 2009: ““Irrigated afforestation of the Sahara and Australian Outback to end global warming” Climatic Change
Abstract: Each year, irrigated Saharan- and Australian-desert forests could sequester amounts of atmospheric CO2 at least equal to that from burning fossil fuels. Without any rain, to capture CO2 produced from gasoline requires adding about $1 to the per-gallon pump-price to cover irrigation costs, using reverse osmosis (RO), desalinated, sea water. Such mature technology is economically competitive with the currently favored, untested, power-plant Carbon Capture (and deep underground, or under-ocean) Sequestration (CCS). Afforestation sequesters CO2, mostly as easily stored wood, both from distributed sources (automotive, aviation, etc., that CCS cannot address) and from power plants. Climatological feasibility and sustainability of such irrigated forests, and their potential global impacts are explored using a general circulation model (GCM). Biogeophysical feedback (Charney 1975) is shown to stimulate considerable rainfall over these forests, reducing desalination and irrigation costs; economic value of marketed, renewable, forest biomass, further reduces costs; and separately, energy conservation also reduces the size of the required forests and therefore their total capital and operating costs. The few negative climate impacts outside of the forests are discussed, with caveats. If confirmed with other GCMs, such irrigated, subtropical afforestation probably provides the best, near term route to complete control of green-house-gas-induced, global warming.
Ornstein L. 2009: “Replacing coal with wood: sustainable, eco-neutral, conservation harvest of natural tree-fall in old-growth forests” Climatic Change DOI 10.1007/s10584-009-9625-z
Abstract: When a tree falls in a tropical old-growth forest, the above ground biomass decays fairly rapidly and its carbon is returned to the atmosphere as CO2. If the trunk of that tree were to be harvested, before decay, and were stored anoxically, or burned in place of coal, a net of about 2/3 of that amount of CO2 would be prevented from entering the atmosphere. If the ash-equivalent of each tree trunk (about 1% of dry mass) were recycled to the site of harvest, the process would be indefinitely sustainable and eco-neutral. Such harvest of the undisturbed old-growth forests of Amazonia and Equatorial Africa could effectively remove about 0.88 to 1.54 GtC/yr from the atmosphere. With care, additional harvest of adjacent live trees, equaling up to two times the mass of the fallen trees, might be similarly collected, just as sustainably, and with almost as little ecological impact. This very large contribution to the mitigation of global warming is discussed – with caveats. It could substantially and ‘immediately’ ‘cancel’ a good deal of coal emissions, but without closing down many presently coal-fired power plants – and at much lower cost and lead-time than carbon capture and sequestration (CCS).
What’s the relevance?
The two strategies together could yield about 8 to 13 GtC/yr (8 to 13 “wedges”) of new bio-sequestration; enough to easily ‘stop’ the current 8.8 GtC/yr increase in atmospheric CO2. By comparison, all other mitigation proposals provide, 1 or 2 wedges each. 8.8 GtC/yr dumped into the atmosphere as CO2 creates a problem of enormous scale, and can only be dealt with – successfully – with equally enormous expenditures of resources. That said, because of the induced rainfall, the typical cost will drop to something like $0.50/gallon of gasoline burned ($0.50/2.3kgC), the total global cost would be about $1.9 trillion/yr (compared to a 2008 US asset price deflation of about $25 trillion). When that’s compared to figures like estimates of $800 billion/yr for CCS, my ‘plan’ looks like a loser. But, CCS can address only about 20% of the 8.8GtC/yr problem at the $800 billion/yr price. My two solutions address the whole thing! CCS would involve a network of dangerous high-pressure pipelines coursing through the most developed neighborhoods of our civilizations – compared to relatively benign water aqueducts in what are presently virtually uninhabited deserts. CCS also requires deep and risky sequestration of CO2, whereas the sequestration in forests is much safer. And although the pressurized CO2 has virtually no value, the forest wood represents a ‘bonus’ of a ‘forever’ sustainable, eco-neutral, conservation harvestable (SENCH) supply of wood and wood products to serve in place of non-renewable fossil carbon – with near zero CO2 footprint!
Better management of forests provides the most practical way to begin to ‘immediately’ reduce atmospheric CO2 and buy enough time to permit energy conservation and the development and testing of new technology to then make even more of a difference. Using wood in place of coal – and at the same time, preventing further deforestation – unfortunately, are intimately tied together. And since deforestation is responsible for the release of about 1 - 2 GtC/yr, it has a large effect on how practical any proposed targets and menu for conservation might be.
The decisions that must be made to accomplish enhanced bio-sequestration often are just those that are also likely to encourage more destructive deforestation by ‘other actors’ – as discussed in my SENCH paper.
When bio-fuels begin to compete seriously with fossil fuels – for example, if ‘effective taxes’ on fossil fuels seem to make wood and corn ethanol attractive alternates, it’s then that market pressures to harvest bio-fuels will become overwhelming and will exert enormous pressures to increase deforestation.
And this is why except for bio-harvests that result in zero or negative CO2 footprint (as carefully defined in my SENCH paper) such harvest must be subject to ‘an effective carbon tax’ in proportion to its positive CO2 footprint – just as has been proposed for fossil fuels – otherwise catastrophic deforestation may proceed with a vengeance! This point isn’t generally understood – even by many climatologists and environmentalists!
[As this weblog was being prepared (10/23/2009) the following paper was published, that makes exactly this point!
TD Searchinger, SP Hamburg, J Melillo, W Chameides, P Havlik, DM Kammen, GE Likens, RN Lubowski, M Obersteiner, M Oppenheimer, GP Robertson, WH Schlesinger, GD Tilman “Fixing a Critical Climate Accounting Error” Science 326, 527-528 [see http://www.princeton.edu/~tsearchi/writings.html].
Abstract: Rules for applying the Kyoto Protocol and national cap-and-trade laws contain a major, but fixable, carbon accounting flaw in assessing bioenergy.
With such ‘taxes’ on fossil fuels in place, the cost of transporting wood and wood products globally becomes no more onerous than the present global transport of petroleum.
We begin with the harvest of fallen trees in the Amazon and Congo, probably using lighter-than-air-ships, like the Boeing SkyHook, to move the harvested logs to a nearest river, and then use river transport to coastal ports. (No access roads or skid trails means surreptitious raping of those old-growth forests remains quite difficult.) This requires a modest investment and no new technologies. And the wood can be stored for a sufficient period for a large fraction of coal-burning plants to be modestly retrofitted to burn wood chip, pellets and charcoal. Nonetheless almost ‘immediate’ CO2 drawdown of up to 4.5 GtC/yr results. During that same period, wood-processing plants are developed in Brazil and Equatorial Africa to process at least part of the wood into charcoal and syngas etc. Some ‘experiments’ in irrigated afforestation of the Sahara, Outback, Thar desert and Saudi Arabia also begin ‘immediately’.
If (when?) other conservation efforts (including wind, solar, electric vehicles, etc.) don’t ramp up fast enough to also begin to result in a significant reduction of atmospheric CO2, then the large afforestation projects commence – and only in proportion to the net projected need – so probably at a cost of (considerably?) less than 1.9 trillion dollars/yr ;-)
Of course ‘effective taxing’ of fossil fuels and those bio-fuels with positive CO2 footprints would have to be negotiated worldwide with some dispatch. Wood and wood products would also have to carry international encryption tags, indicating site and date of harvest and associated CO2 footprint, to assure proper ‘taxation’ and to inhibit the kind of gaming of the system that could lead to deforestation. I see that as the biggest problem.
And effective monitoring and policing agreements and infrastructure would have to be put in place in the Amazon and Congo areas to protect the old growth forests. That’s the second biggest problem.
These kinds of considerations ought to be important parts of the December agenda in Copenhagen.