Bjorn Lomborg: “Morgen gaan we sparen”


(English version here)

Bjorn Lomborg pleit er in het NRC van 25 augustus voor om de CO2 uitstoot niet nu te verminderen, maar pas in de toekomst. Zijn redenering doet me denken aan de spreuk “morgen gaan we sparen”, die in veel huishoudens aan de muur hangt. Wat een mooi voornemen, elke dag weer!

Het probleem met CO2 is enerzijds dat een groot deel ervan honderden jaren in de atmosfeer verblijft, en anderzijds dat het klimaat traag reageert op veranderingen in de broeikasgasconcentratie. Deze combinatie zorgt ervoor dat ongebreidelde uitstoot van meer CO2 tot grote risico’s leidt voor het toekomstige klimaat. In Lomborg’s analyse wordt dit stelselmatig over het hoofd gezien.

Als grote veranderingen, zoals het smelten van grote massa’s landijs, eenmaal in gang zijn gezet door toedoen van een te hoge concentratie aan broeikasgassen, zijn ze niet zomaar omkeerbaar. Het uitstellen (afstellen…?) van emissiereductie gaat met grote risico’s gepaard voor de toekomst. Ook de kosten van uitstel van maatregelen zijn hoger dan die van het nemen van maatregelen nu; dat is de conclusie van bijvoorbeeld McKinsey (zie hier en hier), het Stern review, en de International Energy Agency (zie onder). Voor ongeveer 1% van het globale BNP kunnen we ernstige klimaatverandering voorkomen, is de bottom line (zie onder). De kosten van ongelimiteerde klimaatverandering pakken waarschijnlijk veel hoger uit.

Risico’s die pas in de verre toekomst plaatsvinden worden vaak onderschat, en men getroost zich meestal niet veel moeite om die risico’s te beperken. Neem roken: Stoppen met die ‘fijne’ gewoonte is voor velen blijkbaar een te grote prijs om toekomstige gezondheidsrisico’s te beperken. Daarnaast is het verslavend natuurlijk. Net als ons hoge energieverbruik blijkbaar. In tegenstelling tot roken wordt het actief beperken van klimaatrisico’s ook nog gecompliceerd door de zogenaamde ‘tragedy of the commons’, waar Lomborg dankbaar misbruik van maakt in zijn argumentatie.

Laten we inderdaad naar oplossingen zoeken die de klimaatverandering binnen de perken –en buiten de dijken- zal houden. Een voorwaarde daarvoor is natuurlijk dat we ons baseren op wetenschappelijke inzichten over het klimaatsysteem. Lomborg ziet dat blijkbaar anders.

Enkele kostenschattingen:

IEA: The investment required to prevent dangerous climate change is “an average of some 1.1% of global GDP each year from now until 2050. This expenditure reflects a re-direction of economic activity and employment, and not necessarily a reduction of GDP.” In fact, this investment partly pays for itself in reduced energy costs alone (not even counting the pollution reduction benefits)! (via Joe Romm)

Stern: “Using the results from formal economic models, the Review estimates that if we don’t act, the overall costs and risks of climate change will be equivalent to losing at least 5% of global GDP each year, now and forever. If a wider range of risks and impacts is taken into account, the estimates of damage could rise to 20% of GDP or more.
In contrast, the costs of action – reducing greenhouse gas emissions to avoid the worst impacts of climate change – can be limited to around 1% of global GDP each year.”

McKinsey: “The macroeconomic costs of this carbon revolution are likely to be manageable, being in the order of 0.6–1.4 percent of global GDP by 2030. To put this figure in perspective, if one were to view this spending as a form of insurance against potential damage due to climate change, it might be relevant to compare it to global spending on insurance, which was 3.3 percent of GDP in 2005.”


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2 Responses to “Bjorn Lomborg: “Morgen gaan we sparen””

  1. Heiko Gerhauser Says:

    There is a lot to be said about these reports. Start with McKinsey and the IEA, they include a large fraction of negative cost options. Who would be against those? This kind of leaves unanswered whether nuclear or CCS should be part of the solution.

    The cost curve of the IEA has the first third at negative cost, the second third at modest cost (so the first two thirds come free) and the last third at 100 Euros plus per tonne, but they also only start bringing those in after about 2030.

    I do not agree with Lomborg on everything, but on the hard science I have never seen him deviate from the IPCC line, and much of where you see disagreement is in the rhetoric.

    You can also put the IEA position in Lomborg’s terms. Do what’s free now (the next 20 years) and leave the costly stuff for later (ie 2030+) when it’ll hopefully be much cheaper, maybe renewables with some early R and D support will outcompete fossils anyway then, so it’ll not just be cheaper in 2030 but outright free as well.

    I’ve also seen Hansen say that we should do methane first:

    I think Lomborg is quite good at generating vituperative responses from environmentalist minded people, even when at base there isn’t much in between on actual policy.

    Where I do differ with Lomborg is notably his idea that fundamental research is much better than applied research, most specifically he does not like feed-in tariffs. I am convinced that technology development also involves optimising manufacturing techniques and for that we need manufacturing experience at volume. We won’t get that from throwing a few billion into fundamental PV research, but we can get it from feed-in tariffs. Yes, the sun does not shine a great deal in Germany, but you won’t get German tax payers to pay for PV panels in Mali to ensure more benefit from the electricity generation, and the electricity generation would still not be the main benefit, which actually is to create an industrial base for PV. Mali then benefits from this by getting lower prices for PV panels so that they do actually get installed there as well.

    I want to say a bit more about agronomic models and why it is reasonable to have quite a span there in outcomes.

    You can use agronomic models to look at the effect of changing temperature and precipitation patterns holding everything else constant (including direct CO2 related effects). The bit from the IPCC you quoted is based on that sort of approach I believe.

    The everything else includes where crops are grown, how much effort is put into irrigation and what crops are grown.

    A first level of adaptation is to say that farmers will choose different crops. A second level is to use irrigation schemes and stop farming in some places and start farming in others.

    Adaptation has a big impact on the outcome.

    Nowhere on Earth is actually too hot for plants to grow optimally, but there are places that are actually too cold. It is no co-incidence that biomass productive at the poles is close to zero and highest right at the equator. This means that to have a negative effect on agricultural productivity you need to assume less rain or sticking with crops that have their temperature optimum low, even when there are crops that prefer 30C say and have higher productivity.

    You can also choose to hold everything constant except CO2 itself and that will give substantial yield increases, how much depends on the crop and other limiting factors, but in greenhouse settings for example we are talking 20 to 30%.

    If you presume that water is something we can do something about through irrigation (including both micro measures like drip irrigation and macro measures like moving water from south to north China) and are happy to shift where farmers grow crops and what they grow, and include the effect of CO2, it is very easy to come to very large positive effects from 500 to 1000 ppm CO2 on world agriculture.

    If you have no trust in water technology, hate dams and what they do to the environment, and also believe that it is unacceptable for farmers to stop farming in one area and start farming in another, etc… it is also not hard to come to the conclusion that the positive direct effects of CO2 will be more than outweighed by droughts and floods.

  2. Bart Says:


    The fact that Lomborg publicly states that he accepts the IPCC line distinguishes him from hardcore fanatics such as Fred Singer or Hans Labohm.
    Still, he’s trying to bend and cherry-pick the science to suit his do-nothing agenda, it seems. He’s very smart at doing so. I’ve seen a debate on youtube between a climate scientist (Myles Allan) and him, and clearly he’s a very skilled and persuasive debater. I’m not surprised people are taken in by him.

    “As a lead author of the last IPCC report, I find it gratifying that Bjørn Lomborg sings the praise of the “careful work” of the “hugely respected” IPCC. However, Lomborg misrepresents what we wrote in the report.”
    “it seems like a sober and well-researched presentation of balanced information, whereas in fact it makes use of selective inattention to inconvenient literature and overemphasis of work that supports his lopsided views”
    “the scientific reports that Lomborg uses say the opposite of what he makes it appear they do”
    “He is a master of the false dilemma fallacy” (mostly in Dutch) (for all the nitty gritty details)

    I totally agree with you that just R&D is not enough to bring new technology to the market. Structures also need to be put in place to support green technology to gain some market share, and feed-in tariffs, as eg in Germany, seem to be a great way of doing so.

    About the costs of mitigation:

    It seems to me that these kinds of costs estimates of mitigation are inherently uncertain – even more so than the uncertainties in climate science. Economics is not an exact science, and cost estimates for the future include a fair amount of subjectivity, e.g. about what discount rate to use.

    The cost curve presented in the McKinsey report (, exhibit B, page xiii) specifically mentions both CCS and nuclear; the IEA also puts CCS on their cost curve (costs per ton CO2e as function of amount of carbon replaced/removed). On both, CCS is close to the 2/3rd mark on the cost curve, similar to e.g. windpower, solar, and biomass cofiring.

    I have nothing against going after the low hanging fruit first: methane, black carbon. But let’s not forget that in the long term, CO2 is going to be the main challenge, and that it requires early action to limit the risks.

    About agricultural models / optimal CO2 for plants:

    I don’t immediately trust your guesstimate of an optimal CO2 amount more than I do the collective scientific estimates as laid out in the IPCC reports. It would require me to do a lot more reading on agricultural models to really argue the details though. I would think/hope that some estimates were made taking the output of global climate models as input for an agricultural model. But you’re right, the outcome of such an exercise would still depend on subjective choices such as what crops to grow. I’m not sure though if the people in northwest Europe are ready to give up the potato quite yet. I know people who’ve never eaten anything else for dinner.

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