Copenhagen, again

mt has a a transcript of the Copenhagen closing plenary. Let’s have a look. Better still, go read it yourself. I’m not going to cover it all.

Our conclusion is that recent observations confirm that, given high rates of observed emissions, the worst-case IPCC scenario trajectories (or even worse) are being realised. For many key parameters, the climate system is already moving beyond the patterns of natural variability within which our society and economy have developed and thrived. These parameters include global mean surface temperature, sea-level rise, ocean and ice sheet dynamics, ocean acidification, and extreme climatic events. There is a significant risk that many of the trends will accelerate, leading to an increasing risk of abrupt or irreversible climatic shifts.

My first thought is that this is somewhat ambiguous – do they mean that what is happening *now* is worse, or do they mean that what we now think likely to happen in the future is worse? Or both? My second, is that banking on high emissions from 2008 continuing into the future is dubious – the economic downturn will cure that, at least briefly. Anyway, enough of my quibbles: what did Stephan Rahmstorf make of it, you probably care more about his opinion than mine.

First of all, not everything is worse than expected. So that’s the good news. The global temperature is actually rising just as expected… But there are other components of the climate system that we don’t understand that well for example the sea ice behavior, the continental ice sheet behavior, the sea level, and unfortunately, in these components, where we don’t understand them so well that we can confidently compute them, things seem to go faster and worse than we had expected so far. For example the shrinking arctic sea ice is actually declining much faster than in any of the climate models, and we also sea that sea level over the last 20 years or so is rising about 50% faster than the climate models have projected. Another reason for concern is that if you look at the history of this planet, climate changes – the natural climate changes in Earth’s history, we find that past warm climates were significantly underestimated by models, for example the Pliocene.. And we also find that climate changes in earth’s history often have been very abrupt, that’s another thing that we can’t quite reproduce in the models, and at this conference I’ve seen some interesting evidence as to why some aspects of the climate in the climate models may be systematically too stable, so that in the real world things might actually be more unstable than in our models.

So I think SR is backing off from the conference statement somewhat: their first key parameter – global T – isn’t off on the worst case scenario; it is where we expect. Other more poorly understood components are worse? Maybe. If 2009 is worse for Arctic sea ice than 2007, I’ll concede this point to some extent. As to misestimating past climates, I’m not sure how much that matters – in many cases, we don’t really know what the climate was then anyway. The bit about stability is interesting; would be nice to know more.

Stern: he still hasn’t understood (or more likely read, alas) what mt had to say about lawnmowers (but don’t count on the military to save you. They won’t). And I don’t believe this “we can solve GW with 1-2 percent of GDP stuff”.

Dan Kammen: why aren’t you silly industrial people doing the right thing? You must be so stupid. It is so frustrating, we keep telling you what to do but you don’t do it!

Danish PM: mt thinks he is spot on, I find it hard to agree. He has nothing intersting to say about climate, so it is the econ/pol that is relevant. He appears to take Stern at face value. Probably hard not to, when Stern is sitting next to him, but he must be aware that Stern’snumbers are dubious (me or or me quoting Nordhaus). The European Union has committed to 30% reductions by 2020 as part of a global agreement – sounds great, but there isn’t a lot of sign of that coming to pass.

The bit near the end – about 9/10 of the way down – about different ways of looking at 2 oC target is interesting, to see how confusing it can all get. Among people who have in theory just finished listening to it being very carefully expalined to them.


  1. #1 Magnus W

    Why don’t you believe “we can solve GW with 1-2 percent of GDP stuff”?

    [I can't claim to have looked carefully, but replacing all our energy infrastructure with non-carbon fuels looks far more disruptive than 1-2% of GDP -W]

  2. #2 Adam

    Magnus, we can. Just redefine GDP. It’s an arbitrary definition anyway. ;)

  3. #3 Luke Warmer

    mt’s point on lawnmowers is the planners’ wet dream.

    The tragedy of the commons will soon come to the fore, who maintains and repairs? It’ll be interesting to see how these car share schemes go on when bumps and scratches inevitably appear. Also, who pays up front for the one mower. What if you don’t have a lawn or have a very big lawn etc then you get marginal free-riders.

    Planning to allocate assets is not the answer in a free society. Of course a deranged planner would then want to take this into the house with food blenders etc. Then what about food itself e.g. jam – I always end up throwing away mouldy half-fulls, perhaps if I shared with a neighbour… you could then move to low waste, centralised food kitchens for communities where (choice be damned) at least there’s no waste. Oh yes – and then on to the gulags and salt mines for climate skeptics, I’m assuming.

    There are smarter, market ways – the Green Alliance (and many others) has been pushing for the idea of services as a solution to this issue. Outsource your lanwmowing to a company with economies of scale for owning the best/ most efficient lawnmowers, incentives to keep it maintained, expertise on lawn care etc etc. Plus you get more space in your shed.

    It doesn’t have to be draconian. There are also gains to trade, and comparative advantage allows you to focus on your own skills.

  4. #4 Alexander Ač

    Well, I too think that 1-2 % or even more is quite a non-sense… I would be interested how many people actually believe that doing bit here and even less there is going to *significantly* change anything. That is just self-delusion.

    David MacKay thinks (citing Helm) that Stern underestimates portion of GDP needed to solve GW because of ignoring import/export of the stuff (which domnates!):

  5. #5 JamesG

    “global T – isn’t off on the worst case scenario; it is where we expect”
    Oh really? Pull the other one! It appears to me that you can also summarize SR as saying the models are clearly crap.

  6. #6 Gareth

    On the GDP cost: a recent report by McKinsey suggests that global emissions reductions of 35% below 1990 levels can be done for about 1% of GDP. You need to bear in mind that a lot of the abatement stuff is negative cost (see McKinsey’s abatement curve). Going beyond that will cost more, of course, because you start getting into the stuff that’s currently expensive — but it might/should be cheaper in future.

  7. #7 David B. Benson

    GWP in 2007 CE was about 67 trillion U.S. dollars. One percent is $670 (U.S.) billion dollars, about the size of the U.S. defense budget.

    [I'm not familiar with these numbers or how they are calculated. 1% of anything sounds like a small amount, but perhaps not all of that 100% is freely available. Quite likely it is like family income: a large fraction is assigned to keeping-alive and only a small amount is available for investment -W]

  8. #8 Phil Hays

    “replacing all our energy infrastructure with non-carbon fuels looks far more disruptive than 1-2% of GDP”

    Over what time period?

    Over the next three months? A year? Twenty years? Fifty years? A hundred years?

    Fossil carbon fuels will run out, and we probably don’t want to burn even a quarter of them to avoid the risks of climate change. Longer term, we can’t maintain a fossil carbon fuelled economy at any cost.

  9. #9 David B. Benson

    My point was that US could almost do it alone by not wasting money on the bloated defense establishment.

    [If you believe that 1% will do, yes. My point was that I doubt it is -W]

  10. #10 Eachran

    Dr Connelly, why do you think that the costs of dealing with climate change are more than 1%. For many years now I have believed them to be zero.

    [Well Stern at least disagrees with you :-) -W]

    I read the JQ comments and I am familiar with Messrs Nordhaus Tol Stern and the rest. I would be interested to know what they would write now following the so-called financial and economic crises and also major inter-generational disputes (pensions is one) within most developed countries. Somehow I think that discount rates are the least of our problems even if they could be defined objectively. Incidentally I thought that Mr Annan’s comments on JQ’s blog were correct.

    [Annan is a Dr too. But I haven't read what he says on JQ's blog. Be aware that my opinion on the economics of this isn't worth a lot. I do think we can't just throw away the problem of discount rates though - the question of how much we should, ideally, invest for the depends on it. I think it is clear that we don't have a good way to discover what the correct discount rates are or should be -W]

  11. #11 David B. Benson

    Well, I estimated it out rather carefully. For 1% of GWP, $670 billion per year, I could simply remove all the excess carbon added yearly (at 2007 CE rates) and also remove a tiny bit of the backlog of 500 GtC. Everybody gets to go on burning fossil fuels until those are all gone.

    [Ah, I think you are making what I believe to be a mistake, that of assuming that spending money at the current price of carbon emission credits will actually remove carbon from the atmosphere up to arbitrary amounts. I don't think it is true -W]

  12. #12 Eachran

    I think that you are missing the point on discount rates and you dont need to be an economist to understand it.

    If the cost of change is zero then a discount rate is unnecessary : societies’ dont forego anything for future benefits. The change is part of the dynamic which drives development.

    The reason the cost of change is zero is because the transition to an alternative set of goods and services with an alternative set of prices reflecting a carbon free economy, compared to today’s, can be effected without disruption if effected early enough. To the extent that it is done late (whatever that might mean) then the cost, if any, is the loss of employment to those unfortunate to have lost their jobs as a result of disruption. This is similar to the UK coal miners losing their jobs or Kodak employees losing theirs with the onset of the digital age.

    Even with disruptions, economies tend to realign rapidly and the unemployed become employed anew.

    People are used to consuming differently at short notice and there is no reason why that shouldnt continue.

    But to argue that there is a cost in transforming one basket of goods and services to another, acceptable to consumers, seems to me nuts. It is a bit like arguing that we shouldnt have moved from tablets of stone to HP printers because of the cost involved.

    So far as Mr Stern is concerned, I dont much care whether he agrees with me or not. Before he wrote his report I was saying that the cost of change was zero and I would have been surprised if his report was far out : it wasnt. The range he gave was plus minus but for the wrong reasons. I cant say that I am bothered (too much) with the reasons for a result if the result is broadly correct.

    I am interested to know why you think that the cost of change is significant : it isnt. Happy to help you out if want.

  13. #13 David B. Benson

    For $65 per tonne of carbon removed there are many differnt methods to be empoyed to permanently remove 10+ GtC; not just one.

    I don’t know, nor care, what the price of carbon emission credits might be. The analysis was to find inexpensive ways to remove the carbon.l Around $65 per tonne was the best I could find.