There’s a constant drumbeat of climate stories… Stories that show sensitivities on the low side, interpreted as “we’re saved” if you’re lucky, and “see those climate scientists were lying for the grant money” (how does that work again?) if you’re not.
Then stories that show that model-based estimates are inherently biased toward understatement, which are interpreted as “we’re doomed” and “all skeptics are in the employ of Exxon” (which, at least, seems like it might work for some people.) What are we to do?
Ignore (for the moment at least) that the former was pretty much trumped-up op-ed stuff by a libertarian, and the latter was peer-reviewed science by recognized researchers in a major journal. Let’s pretend, for the sake of argument, that they are equally credible. How, then, should we calibrate our policy position?
A recent conversation on this site adds some context. OPatrick says:
I’m sceptical of the ‘need for a doomy narrative’ – there is no need beyond the narrative available in the science, though possibly with an additional emphasis on the conservative nature of that science and a focus on worst-case scenarios which do, and should, have a greater significance in policy making.
Several important meta-issues are raised in this sentence. First, there’s the claim that there is no need to overstate the science – that the evidence is compelling enough on its own without a need for overstatement. This seems true to most of us here, though it seems manifestly untrue to the naysayer club. To some extent we are trying to get beyond talking to them or about them here. We are trying to discuss what actually we ought to do conditional on the science being roughly unbiased.
Second, there’s a somewhat competing claim that the science has a “conservative nature”. This can be expanded upon in several ways:
- Contrary to naysayer opinion, grants do not go preferentially to scaremongers; indeed they do not go preferentially to scientists in the public eye at all. This is why for the most part only the most accomplished scientists and the least ambitious ones are willing to make public statements at all. This applies across science and not merely in climate. Hopefully this is now changing.
- Contrary to naysayer opinion, for the most part the social and political inclinations of older climatologists is distinctly socially conservative, and heirarchical. Its client disciplines traditionally have been the agriculture and military sectors, after all. Climate scientists no more want to believe the worst scenarios than anybody else does.
- Simulation modeling, our best prognostic tool, is severely limited. Nobody really knows how well these tools can project into the future. While many greatly underestimate the successes of these efforts which have genuinely emergent weather-like behavior, it is important to realize that in the end they are tweaked to present a reasonably reality-like dynamic. That tweaking may make the models a bit too stubborn in reproducing the present day. What’s more, they cannot possibly account for unknown-unknowns, and the more we disrupt the system, the more likely the unk-unks come into play.
- Notwithstanding the myth of the celebration of the paradigm-buster, science is largely a collaborative process, and nobody wants to stray too far from the herd. This is a real concern and it cuts both ways – evidence taking us too far from the consensus will be regarded with suspicion whether it is optimistic or pessimistic
OPatrick’s claim is that the standard IPCC narrative is “doomy enough” but may still be understated.
Finally, there’s the claim that worst cases should dominate the policy discussion. This is essentially the “uncertainty is not your friend” argument. If the chances really were 80% that there is no serious risk, 15% that IPCC is roughly correct, and 5% that it is a severe underestimate, that 5% is entirely salient. A 5% chance of things being worse than the scientific consensus is nothing to sniff about. As individuals we buy insurance against comparable risks.
Put in the context of the other two points, it seems quite foolish to behave as though there were as much as 80% chance that IPCC is greatly excessive. This means that our current behavior is grossly irrational.
Recent evidence, though, allows us to finesse the discussion of climate sensitivity. After all, nobody really cares to what extent the global mean surface temperature increases, except to the extent that it impacts human and natural processes at individual locations and small regions. That is, there’s the sensitivity we’ve gotten habituated to arguing about, along with a vague presumption that an increase of 2 C globally is barely tolerable, 4 C would be enough to set us moving backward, 6 C would probably start killing us off. These are nothing like scientific judgments – they are SWAGs.
That is, we have a poorly specified, poorly understood biotic/economic sensitivity to a relatively well-understood relatively well-constrained physical sensitivity. For some reason we argue endlessly about the latter. I wonder sometimes if all this “skeptic vs consensus” talk isn’t just a pathetic planetary bike-shed argument.
The thing is that this argument is the best we can do until it isn’t. It is the best we can do until actual, as opposed to imagined, impacts start to arise. And well, it is Mr Shadow on the line. Consider what we have arguably seen this past year, all with connections to climate change. I will quote Eli’s admirable summary of Laden et al’s admirable list of 2012 climate events:
- Super Storm Sandy
- Sandy and Sea Level Rise
- Extreme Ice Melting
- Sea Ice Loss Changes Weather
- Ice Loss in Greenland
- Massive Ice Islands
- Increases in Greenhous Gases
- It Got Hot
- & That Brought Killer Heat Waves
- In Many Places the Year Without Spring
- Deadly Wildfires
- Massive Droughts
- River Traffic Stopped
- Very, Very Bad Storms
- Widespread Tree Mortality
- Biodiversity Decreases
- Changes in Atmospheric Circulation
- Phony Science Heartland Institute Implosion
Well, okay, we all enjoyed that last one. But on the whole, it isn’t a pretty picture, and that is just what we are looking at with well less than 1 C above the baseline (Holocene, or hockey stick shaft) temperature. We should just leave the global mean temperature out it. This is what 100 ppmv CO2 above baseline (along with other anthropogenic inputs) can do. Are we really content to go to six or eight times that distance from normal forcing?
The laissez faire argument simply holds no water. It is an absurd and tragic failure of civilization that we’re still discussing whether it does.