Carbon Confusion

Lately I’ve noticed a lot of misconceptions about how various policy instruments for GHG control actually work. Take this one, from Richard Rood in the AMS climate policy blog:

The success of a market relies on liquidity of transactions, which requires availability of choices of emission controls and abatements. The control of the amount of pollution requires that the emission controls and abatement choices represent, quantifiably and verifiably, mass of pollutant. In the sulfur market, there are technology-based choices for abatement and a number of choices of fuel that have higher and lower sulfur content. Similar choices do not exist for carbon dioxide; therefore, the fundamental elements of the carbon dioxide market do not exist.

On the emission side, the cost of alternative sources of energy is high relative to the cost of energy provided by fossil fuels. Also sources of low-carbon dioxide energy are not adequate to replace the energy from fossil fuel combustion.

The development of technology requires directed, sustained government investment. This is best achieved by a tax (or fee) system that generates the needed flow of money. At the same time the tax should assign valuation to carbon dioxide emissions and encourage efficiency. Increased efficiency is the best near-term strategy to reduce carbon dioxide emissions.

I think this would make an economist cringe. Liquidity has to do with the ease of finding counterparties to transactions, not the existence of an elastic aggregate supply of abatement. What’s really bizarre, though, is to argue that somehow “technology-based choices for abatement and a number of choices of fuel that have higher and lower [GHG] content” don’t exist. Ever heard of gas and coal, Prius and Hummer, CFL and incandescent, biking and driving, … ? Your cup has to be really half empty to think that the price elasticity of GHGs is zero, absent government investment in technology, or you have to be tilting at a strawman (reducing carbon allowances in the market to some infeasible level, overnight). The fact that any one alternative (say, wind power) can’t do the job is not an argument against a market; in fact it’s a good argument for a market – to let a pervasive price signal find mitigation options throughout the economy.

There is an underlying risk with carbon trading, that setting the cap too tight will lead to short-term price volatility. Given proposals so far, there’s not much risk of that happening. If there were, there’s a simple solution, that has nothing to do with technology: switch to a carbon tax, or give the market a safety valve so that it behaves like one.

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Friendly Climate Science & Policy Models

Beth Sawin just presented our C-ROADS work in Copenhagen. The model will soon be available online and in other forms, for decision support and educational purposes. It helps people to understand the basic dynamics of the carbon cycle and climate, and to add up diverse regional proposals for emissions reductions, to see what they imply for the globe. It’s a small model, yet there are those who love it. No model can do everything, so I thought I’d point out a few other tools that are available online, fairly easy to use, and serve similar purposes.


From MNP, Netherlands. Like C-ROADS, runs interactively. The downloadable demo version is quite sophisticated, but emphasizes discovery of emissions trajectories that meet goals and constraints, rather than characterization of proposals on the table. The full research version, with sector/fuel detail and marginal abatement costs, is available on a case-by-case basis. Backed up by some excellent publications.


Ben Matthews’ Java Climate Model. Another interactive tool. Generates visually stunning output in realtime, which is remarkable given the scale and sophistication of the underlying model. Very rich; it helps to know what you’re after when you start to get into the deeper levels.


The tool used in AR4 to summarize the behavior of 19 GCMs, facilitating more rapid scenario experimentation and sensitivity analysis. Its companion SCENGEN does nice regional maps, which I haven’t really explored. MAGICC takes a few seconds to run, and while it has a GUI, detailed input and output is buried in text files, so I’m stretching the term “friendly” here.

I think these are the premier accessible tools out there, but I’m sure I’ve forgotten a few, so I’ll violate my normal editing rules and update this post as needed.

Next Generation Climate Policy Models

Today I’m presenting a talk at an ECF workshop, Towards the next generation of climate policy models. The workshop’s in Berlin, but I’m staying in Montana, so my carbon footprint is minimal for this one (just wait until next month …). My slides are here: Towards Next Generation Climate Policy Models.

I created a set of links to supporting materials on

Update Workshop materials are now on a web site here.

Dimensions of The Deal

In the Tällberg event we talked a lot about the deal we need, without really defining what was meant by that. I think it has at least four dimensions:


What science drives the goal? Is it 350ppm? 450ppm? 550ppm? 2C?


What regions or sectors will move first, and what transfers will the rich or the winners use to induce the poor or the losers to play along? Do transfers consist of money, intellectual property, or both?


What form will commitments take, who will make them, and how will they be implemented? Will the mechanism favor taxes or trading, for example? Will standards be expressed as intensities or absolute emissions or … ? How will goals and mechanisms adapt as we learn about uncertainties?


We don’t have a deal now because we don’t have the coalition needed to make it happen. Some combination of the public, politicians, media, religion, education, etc. needs to come together to create critical mass behind a policy. We have fragments (the EU, California) but not a whole. I rather doubt that there is a quick, transformative solution (unless catastrophe drives us to one, which I’d rather not contemplate).

I say “critical mass” deliberately, because what we’re all implicitly searching for is a reinforcing feedback that will grow policy out of its current dysfunctional state. The question is, what is that loop? My guess is that it involves starting gradually. Don’t shoot for the moon and fail. Instead, take a little medicine at first. Impose a modest carbon tax. Observe that the economy doesn’t collapse, and efficiency is cheap or even profitable. Greentech gets a little more profitable, and the more numerous low-carbon voters grow to enjoy their tax rebates. Enlisting their support allows the tax to be ratcheted up further, and soon you’re rolling toward real emissions controls. But is the gain on that loop high enough to yield emissions reductions in time to avoid catastrophe?

Hansen on The Deal

Jim Hansen kicked off the Tällberg panel with a succinct summary of the argument for a 350ppm target in Hansen et al. (a short version is here). As I heard it,

  • The dangerous level of GHGs in the atmosphere is lower than we thought.
  • 3C climate sensitivity from fast feedbacks is confirmed; the risk is slow feedbacks, which are not as slow as we thought.
  • There is enough warming in pipeline to lose arctic ice, glaciers, reefs.
  • Good news: we need to go back to the stable Holocene climate.
  • The problem is solvable because conventional oil and gas are limited; we just need the will to not burn coal, oil shale, etc., except with CCS.
  • Among other things, that requires a price on carbon; for which a tax is the preferred mechanism.
  • The only loser is the fossil fuel industry; we simply need to bring them to heel.

Hansen was a little impatient with our bit of the forum, and argued that our focus on regions (and the challenges in reaching a regional accord) was too pessimistic. Instead, a focus on fuels (e.g., phasing out coal) provides clarity of purpose.

My counterargument, which I only partially articulated during the session, for fear of driving the conversation off on a tangent, is as follows:

As a technical solution, phasing out coal and letting peak oil run its course probably works. However, phasing out coal by 2030 implies a time constant of seven years or a rate of decline in coal utilization of about 10%/year (by the 3-tau rule of thumb). Coal-fired power plants have a long lifetime, so the natural rate of decline, assuming no new coal investment, is more like 2.5% or 3%/year. Phasing out coal at 10% per year implies not only halting construction, but also abandoning many plants before their natural economic lifetime is up. Age structure complicates things a bit, perhaps making it easier in the US (where plants are disproportionately old) and harder in China (where they’re new). Closing plants ahead of schedule is going to make the fossil fuel interests that Hansen proposes to control rather vocally upset. Also, eliminating coal emissions that fast requires some combination of rapid deployment of efficiency, noncarbon energy sources, and CCS above natural rates of capital turnover, and lifestyle change to pick up the slack. That in itself is a significant challenge.

That would be doable for a coalition with enough political power to either overpower or buy off the owners of stranded assets. But that coalition doesn’t now exist, and therein lies the reason that this is a political problem more than a technical one.

Tol Talks Tax

Stumbled upon while searching for a reference: Richard Tol Changes Tune, Talks Carbon Tax. From what I’ve read, Tol is too much of a nonconformist to club with the professional skeptics, and has probably always preferred a Hotelling-style carbon price trajectory, so I’m not convinced that this is really a change, but it’s intriguing.

Aviation Pontification

Last week I presented in an INFORMS 2008 panel, Role Reversal: The Impact of Climate Change on Aviation. My slides are here (you’ll miss a model demo using a carbon cycle/climate model, but that wasn’t central). I got challenged on one assertion – that participation in regional initiatives is meaningful – on the grounds that federal preemption definitively assigns aviation regulation to the national level. That may be so, but I suspect that mental models formed through regional experimentation will still shape what happens nationally. Without early involvement, aviation could find itself getting pounded into the nearest available policy pigeonhole, regardless of fit. Avaitors joke that, “gravity never loses; the best you can hope for is a draw.” The same could perhaps be said of aviation’s chance of withstanding the inexorable consequences of GHG accumulation.

The Deal We Ain't Got

Today, Drew Jones and I presented a simple model as part of the Tällberg Forum’s Washington Conversation, ‘The climate deal we need.’ Our goal was to build from some simple points about the bathtub dynamics of the carbon cycle and climate to yield some insights about what’s needed. Our aspirational list of insights to get across included,

  • stabilizing emissions near current levels fails to stabilize atmospheric concentrations any time soon (because emissions now exceed uptake of carbon; stabilization continues that condition, and the residual accumulates in the atmosphere)
  • achieving stabilization of atmospheric CO2 at low levels (Hansen et al.’s 350 ppm) requires very aggressive cuts (for the same reason; if carbon cycle feedbacks from temperature kick in, negative emissions could be needed)
  • current policies are not on track to meaningful reductions (duh)
  • nevertheless, there is a path (Hansen et al.’s “where should humanity aim” paper lays out one option, and there are others)
  • starting soon is essential (the bathtub continues to fill while we delay – a costly gamble)
  • international negotiation dynamics are tricky due to diversity of interests, coupled problem spaces, and difficulty of transfers (simulations shadow this)
  • but everyone has to be on board or little happens (any one major region or sector, uncontrolled, can blow the deal by emitting above natural uptake)

A good moment came when someone asked, “Why should we care about staying below some temperature threshold?” (I think a scenario with about 3.5C was on the screen at the time). Jim Hansen answered, “because that would be a different planet.”

The conversation didn’t lead to specification of “the deal we need” but it explored a number of interesting facets, which I’ll relate in a few follow-on posts.