This week's New Scientist has a special feature on advances climate scientists have made recently in medium-term (ten year or so) climate forecasting. This is a question of considerable political significance as I shall explain shortly. But in order to do that, I must first set out a small amount of context.
The article mainly focuses on the work of Doug Smith's team at the Met Office Hadley Centre, which is attempting 10-year climate forecasting based on analysis of the oceans. It also relates the forecasts of Smith's models to certain findings of the Leibniz Institute of Marine Sciences that generated a fair amount of media interest earlier this year - namely their forecast that global surface temperatures may well not increase over the next decade. Smith's team forecasts six further years of plateau. Neither team's work has achieved consensus support at this stage, but both are mainstream (as witnessed by their discussion in New Scientist). In particular, both teams are absolutely mainstream in their analysis of global warming and the role of human greenhouse gas emissions as a contributor.
As with many standard novel scientific ideas, these medium-term forecasts are currently under considerable challenge by other scientists - as I said, they are far from achieving consensus support. But let us consider, for a moment, what it would mean, politically, if these forecasts are right. What would be the political implications if global surface temperatures were not to rise for another six to ten years?
Remember that global surface temperatures have not risen so far this century. Obviously that does not prove that global warming has ceased, any more than the period of cooling from the 1950s to the 1970s proved that we were in a sustained period of global cooling, or than the warming period from the 1980s to the late 1990s proved that there was indeed sustained global warming. The thesis relates to timescales of centuries, not of decades.
Further, standard models that predict long-term global warming are unsurprised by the period of global surface temperature plateau of the past decade, just as, if Doug Smith's team's analysis comes to be accepted, they will be unsurprised by a further six to ten years of plateau. From the scientific point of view, the period of relatively rapid warming from the 1980s to the late 1990s and the plateau from 1998-2014/2018 will all be covered by their models. Thus, the New Scientist leader contends that, although a period absent global surface temperature rise may encourage those the main article describes as "climate change deniers" (a disappointing term to find in a publications that considers itself scientific), there should be no policy implications of this as "politicians have a responsibility to take the long view."
The leader column is quite wrong, of course. If there is going to be a twenty-year plateau, that will be of great policy significance, in two ways: first, for the technical reason that this will change the cost-benefit analysis of certain policy measures, limiting materially the instances in which attempts to prevent action are worthwhile; and second for the political reason that it is likely to mean that any material effort to limit global warming, even if it were feasible and justified in policy terms (which is most unlikely), will not be feasible in political terms - if we believe these medium-term forecasts, that would be a strong reason for changing the political stance away from attempts to counter or limit climate change, and towards an overall strategy of attempting to adapt to climate change.
As I have set out before, my own view is that it is reasonable to assume, for policy purposes, that there is indeed global warming and that human CO2 releases are a material contributor, but that one should put zero weight on any climate change scenario that involves global catastrophe. And some measures to limit the scale of global warming and/or to adapt to it may well be worth doing. However, each such measure should be considered on its own merits.
We have had, in the UK, a debate in the policy realm that focused on scientific issues, often involving participants on either side neither of whom in fact were well-placed, in terms of scientific knowledge, to comment. This has led the public to believe that the crucial question was whether there is, in fact, man-induced global warming. Once that debate had been (by-and-large) settled, it then appeared that the general policy stance followed automatically: if there is man-induced climate change, then we should try to do something to prevent it. But whether we should do anything about it (if there is anything to do) is emphatically not a scientific question. It is an economic/political question. Scientists may feel inclined to tell me to know my place if I were to debate with them details of their models. Fair enough. But I feel equally inclined to tell scientists that they don't know what they are talking about when they urge that we must act to try to prevent climate change - that question falls under my expertise, guys, not yours.
My own view is that although there probably is man-induced climate change, it is most unlikely that, from a policy angle, we should make anything beyond quite limited speculative attempts to try to prevent it. Summarising fairly briefly, so as not to overly repeat old ground:
- The private sector might come up with some clever technical wheeze to counter or limit climate change - indeed, I suspect that some limited innovations on this front are highly likely, and over the longer term inevitable - but I don't see any particular reason for large-scale government action (e.g. research subsidies) to encourage anti-climate-change innovation. It just doesn't seem very plausible to me that there is going to be a solution of that sort in the short term, whilst in the longer term the Market will provide us with solutions.
- People say: "But don't you care about your children?" Of course I care about them. But since, by the time climate change starts to have a material impact, my descendents are going to be about five times as wealthy as me, and since they will be doing this on the back of extensive economic innovation that my generation will produce but my children's children won't be paying us anything for, I don't feel any different about leaving them a bit of pollution to clear up than I do about leaving them a bit of national debt to pay back. They'll be much richer than me. They don't need my pity or charity. They can sort it out. (Of course, it does not follow that I should not be concerned about polluting, merely that my reasons, if any, for objecting to polluting are not a concern for the welfare of my descendents.)
- Limiting human development so as to limit climate change would be enormously costly in the long-term, with implications beyond our current imagining. And in much the same way, the lot of humanity in one hundred years' time will have advanced beyond our own modest horizons in ways we cannot begin to imagine. It is, in my view, and on general principle going far wider than the global warming discussion, arrogant and ridiculous for us to imagine that we can offer any material help to people in one hundred years' time by restricting human development today. This does not mean that we should never restrict development. It just means that we should have different reasons for doing so.
- Contrary to nonsense of the nature of "Burn up" or "The day after tomorrow", the likelihood that many billions of people (or, in the case of Burn up, the whole human race) will die as a result of global warming is precisely zero. We are not, contra many greens, involved in a desperate race against time to do as much as we can before it is "too late". Rather, we are involved in perfectly normal policy-making in which there may be sensible things to do to attempt to limit climate change rather than to adapt to it - who knows, maybe limiting greenhouse gas emissions from coal-fired power stations, or using a bit more nuclear power than we would otherwise do? - but each proposal should be considered on its own merits and subject to standard impact assessment. Adaptation will not be so bad - human action may well have caused material global climate change over the past two centuries, but the tradeoff between human development and climate change has enormously favoured the maximising human development strategy thus far and is overwhelmingly likely to favour maximising human development over the next century, also.
- In a standard impact assessment, we would discount impacts in the future. Even were there no scientific uncertainty about the impacts of global warming (and obviously there is), there would still be considerable economic uncertainties. The discount rate depends on these uncertainties. At the relatively high discount rates it should be appropriate to use in assessing climate change impacts, it is likely to make a material difference to the overall assessment of any measure if there is really going to be no global surface warming over the first decade. Even if this is not of deep scientific significance, it is very probably of policy significance. At the margin, measures that might be worth undertaking to limit global warming if there were to be impacts within the first decade might not be worth undertaking if surface temperatures were to be unchanged for the first decade. Indeed, in virtually any other context, effects that were as uncertain as those associated with global warming and that would not occur within a decade would be policy-irrelevant. (This is the first of our two key consequences.)
- Before the Stern Report, there was a growing economic literature on whether it was better to try to prevent climate change or to adapt to it. The developing consensus in that literature was that it was almost certainly better to adapt. That literature was less methodologically imaginative in a number of ways than the Stern team's work. The Stern report was an important and interesting contribution, but its authority for policy purposes should have been nugatory. There may have been a strong consensus amongst scientists that there is man-induced climate change. But there is not remotely a consensus amongst economists that it is worth doing anything to try to prevent it. Indeed, insofar as there is anything amongst economists approaching a consensus on this issue, it is that most of them would say in private down the pub after a couple of beers that they thought there is virtually no economic case for attempting to prevent or limit climate change. Amongst economists, I would be more optimistic than average about how worthwhile it might be trying to limit climate change. To almost all other economists' mind, that politicians will bring in measures to attempt to prevent climate change is inevitable background - like the mountains or the common cold.
But that brings me back to where I started. For although, in a scientific sense, surface temperature warming from the mid 1980s to the late 1990s may not have been significant, in a political sense it undoubtedly was significant. The chances of the British public voting for politicians advocating sacrifices (taxes, regulations, etc.) to prevent global warming if Britain had, say, been in the grip of a decade of especially cold winters would, I submit, have been about zero. But in the 1990s, people thought they could see climate change all around them. And that created a lens through which they viewed subsequent events. Every hurricane, every report of flooding, every record hot summers day since the late 1990s has seemed to confirm in the voter's mind that, indeed, there is climate change in action.
Even with this lens, however, many in the public remain sceptical. If it really is the case that there is going to be a further period of plateau in global surface temperatures, perhaps extending to 2018, I confidently predict that public appetite for making sacrifices to try to limit global warming will vanish. By 2018, global surface temperatures will, on this tale, have been unchanged for 20 years. There will be voters in a 2018 General Election who would have lived their entire lives without global surface temperatures rising. Indeed, my guess would be that public appetite will vanish by around 2012. If an incoming Cameron administration in 2010 really wanted to implement any measures to try to limit global warming, I believe that would have to be done within the first two years. On the other hand, that might be a most infelicitous time to be asking the public for sacrifices. We are likely at that point to be either still in or just coming out of a very difficult period for the British economy. House prices, for example, will probably still be falling rapidly in 2010. We might even be fighting off the threat of deflation at that point. Thus the temptation will surely be to say that green measures should be put off until another day.
So, Cameron seems unlikely to be able to implement serious green measures at the very outset of his administration. And by 2012/13/14, if standard climate forecasting models are correct and my analysis of the voter implications of that are correct, it will become politically highly unattractive to do anything. He won't be able to act early, and if he doesn't act early, he won't be able to act at all. That sounds to me like something undeliverable. It seems to me that, if Cameron's people believe these medium-term climate forecasts, that would be a strong reason for revisiting the whole policy stance - perhaps still being vigorous in accepting a climate change narrative, but instead urging the necessity of adaptation - and such forecasts certainly provide a strong reason to avoid making any overly-solid commitments to climate change combatting policies in the short term.