Wednesday, November 08, 2006

Is (climate) change bad?

I put this on RealClimate and then globalchange (where comments would be most appropriately directed) but perhaps it's worth repeating here...

I spotted an interesting comment on RC, in the thread following the recent post "How much CO2 emission is too much?":


and a few subsequent replies to me

My comment on the comments on the comment on the comment on the comment got longer and longer and I repost it here as a more suitable forum for discussion:

Re 34, 35, 37, 39:

Even if one assumes the premise that we are "optimally adapted" to the present climate (which I think would be difficult to rationally defend), it does not follow that changes to the climate would result in net costs.

In fact, our adaptation to the current climate (eg in agriculture and infrastructure, as have been mentioned) is also a matter of economics, technology and politics, and we can guarantee that these will continue to change at quite a rate.

Of course we can all agree that a drought in an area that is already somewhat short of water is a bad thing that will likely cost money, compared to exactly the same situation without the extra drought. However, an increase in rainfall in such an area is likely to be beneficial (so long as it is not excessive and leads to flooding), even if society is well adapted to the status quo. The opening of the Northwest Passage is likely to bring significant economic benefits by reducing transport costs, even though (of course) we are currently adapted to its impassability. Warmer winters will reduce the winter death rate in the UK for sure, and this vastly outweighs any plausible estimate of heatwave deaths, at least for a range of modest warmings, even before we start to consider any adaptation to the summer heat. We could of course achieve a similar effect by insulating homes and reducing poverty, of course, but we are already "optimally adapted", right?

To boldly assert as axiomatic that "change = bad" is, I think, rather naive and simplistic. All sorts of (social, economic, technological) changes are inevitable, and the latter two at least have a strong record of bringing substantial (no, massive) benefits. Would anyone be silly enough to argue that these changes are bad because we are adapted to the status quo? While I am sure that some climate changes will increase pressure on some ecosystems and human societies, it seems to me to be a rather more nuanced situation than some of the comments above would indicate. Indeed, if the climate changes are slow and modest enough compared to the other changes, it might be hard to detect their overall effect at all (on human health, wealth and happiness, I mean - of course I'm sure it will be easy to measure environmental parameters that document the climate change itself, indeed this is already clear enough). I'm sure UK residents will have noticed the substantial northward march of maize as a crop in recent years (for cattle fodder). I'm not sure to what extent this is due to politics (subsidies), economics, climate change, breeding of better-adapted varieties, or even just farmers gradually realising that it grows better than they had thought possible. Even if climate change is the largest factor (which I doubt, but it's possible), it is not clear who lost out here, other than perhaps the bugs that prefer to live on kale (or whatever the displaced crop was).

Living as I do in a country where houses are expected to last about 30 years, I find it hard to take seriously any worry that they might not be optimally adapted to the climate 100 years hence (let alone the sea level a few centuries later). Note also that a change in fuel prices would change the optimal amount of insulation irrespective of climate change. Likewise, advances in building materials will likely render current designs somewhat redundant.

Extropians would assert that "change = good" and that we should encourage change unless it is proven harmful. Just to be clear on this, I do not endorse this point of view 100% but the difference in opinion seems as much philosophical as scientific. I think that understanding this POV goes a long way to explaining the differences between the environmentalists and the sceptics (even if it does not excuse the dishonesty of the denialist wing).

I hope this doesn't sound too much like a septic handwave, expecting techology to magically save the day. To the extent that climate change is rapid or substantial (which I will deliberately leave undefined here!), of course it's a threat that should be taken seriously. It is a little scary to think about how dominant the human influence can be, and perhaps a mental model of some hypothetical stasis is a comforting thought in which to ground our personal philosophies. But it would be a mistake to let one's comfort zone unduly colour one's perceptions of reality (or at least, such effects need to be openly considered and one should be prepared to see them challenged).

In case it's not clear, I'm not actually trying to argue that the expected changes are necessarily (or even likely) a good thing. But I was struck by the extent to which some people were asserting that no change would automatically be the best possible outcome, and moreover that this was a logical/scientifically-based judgement.


EliRabett said...

You are very much a child of the Rennaisance (sp??). Progress is not guaranteed, nor is change. So saith the sour old guy

Anonymous said...

Is it possible to calculate the climate that gives the maiximum non-glaciated, non-submerged land area? That might be a starting point for best possible climate for as long as we continue to live on land.

Anonymous said...

I think similar as how it's hard for a layperson to imagine a global mean temperature, it's also hard to imagine the impact of this rising or falling. I remember a "debate" in London with a guy I work with (ostensibly on the pro-AGW side) versus some Icelandic glaciologist (the "skeptic") who said he welcomes a few degrees increase. But that's just his localized Icelandic view that "gee, sounds like we'll be a little warmer," and neglecting the effect on the rest of the world. Sort of an American-style viewpoint when you think of it ("it's good for us, it must be good for everyone!")

EliRabett said...

Now that I have some time, allow me to point you to the bunny's take on the whole thing, along with the better comments.

"Recalling that civilization has existed while the global temperature was in a rather limited range, maybe +/- 1 or 2 C from today, I think that the answer is rather clear. Given that the global temperature in recent ice ages was only about 8 C lower than today, I think we have a pretty strong lower bound on that too."

Some of the comments are rather too the point. That was another Rabett Run prescient feature posting

James Annan said...


That's an interesting calculation. I guess the answer would be colder than today. However, one might consider permafrost to be equally useless as ice-sheet, which might tip the balance to a warmer world.

In terms of agricultural productivity (which I guess is the underlying motivation for your question), I think there is little doubt that significant warming would bring a net gain globally - albeit with local losses.

Anonymous said...

Time to quote a septic?

"I am persuaded to think that any climate change is bad because of the investments and adaptations that have been made by human beings and all of the things that support human existence upon this globe. Even minor fluctuations of climate could change the distribution of fish, ... upset agriculture,...and inundate costal cities...... Such changes could occur at a faster rate perhaps than human society can evolve."
S. Fred Singer, ed. 1975. The Changing Global Environment pp5.

Even some apparently obvious beneficial effects like your added rainfall in a dry area may cause problem as new water borne parasites will gain a foothold in an area where people have no experience and no immunity to them.

Since I live in a 60 year old house that is not considered old by our standards I'm also less than impressed by an argument that houses should be replaced every 30 years. Renovated, sure, but not torn down and rebuilt.

Anonymous said...

Working from a scenic bushwalking point of view, a college friend and I calculated that the optimal global climate for recreational hiking would be about 1/2 to 1 degree cooler. We figured this would give better mid-latitude alpine snowfields and glaciers, without seriously changing sea levels, burying the canadian islands in ice, etc.

James Annan said...


That would, however, curtail the walking season for many - although the small proportion who relish snow and ice might be happier.

C W Magee said...

James, the curtailing of high altitude/latitude hiking would be compensated for by increased walking seasons in arid and tropical envorinments.

skanky said...

On the excess deaths in winter issue, there are a number of studies (see Google scholar) that point out that colder countries than the UK (Austria, Scandinavian countries etc) have lower rates than the UK, and that (aside from UK average min temps), the main factor is the quality of the housing (colder damper properties). As one method of AGW mitigation for the UK is to bring the housing stock up to Scandinavian standards, it seems that the excess winter death toll could be cut at the same time.

As this would keep houses cooler in summer as well, it would also help adapt to the warmer summer temperatures.

Thus the costs of some mitigation measures can be off-set against current problems that need resolving anyway.

This also suggests that the UK is not optimised to current climate in all respects, but how well matched it is compared to other variations would need to be looked at (and the same exercise carried across the globe).

Going off on a tangent, it would be interesting to compare excess winter deaths against other factors (economic, political, historical, etc) allowing for winter average variations.

Anonymous said...

No doubt all we can do now is adapt and prevent more damage. But I guess we should also ask ourselves some questions: How did we get in this situation anyway? What caused climate change? I have read many theories, but one of them I have found very interesting: war at sea was often ignored, but if you analyze it for a bit, it makes sense! Check to see what I mean.

Brian said...

There's a huge difference between an ice sheet and permafrost in terms of the land's value to humans. Also between a continental ice sheet (not valuable) versus alpine glaciers (quite valuable for water storage).

More important saying the argument is "change=bad" is a very unfair formulation. Try this one: "change from a situation we're adapted to is more likely to be bad than good". Showing a few examples that are good (and talk to the Eskimos about whether an ice-free Arctic is "good") doesn't defeat the proposition.

James Annan said...


The point of this post was not to complain about people who look at the evidence, and conclude based on a reasoned argument that the present and likely future changes are going to be bad overall - rather, it was the prior presumption that change is a bad thing, simply because it is change, that I was objecting to.

I think you'd be hard pushed to claim that we are "optimally adapted" to this particular climate, and even if we were, it still would not necessarily follow that a changed climate would not be an improvement. For a trivial example, consider the effect of warming on reducing winter deaths and heating costs. Sure, there are extra aircon costs in the summer. An overall assessment of good v bad is a complex (and often significantly subjecting) process of weighing up competing and not clearly commensurate claims, not something that can simply be asserted as a trivial axiom. At least, not by me!