Has the world actually been cooling since 2002?

[Sam_Stone]

@wolfpup

Not at all. Certainly when the temperature skyrockets for 30 years at the end of the 20th century it’s something worth noting, but even then, no legitimate scientific endeavor was putting a metaphorical ruler to it and claiming that the slope of the trend line told us everything we needed to know about future climate change, or indeed that the slope of this particular trend line was uniquely significant. Entirely the opposite. Science was exploring the underlying mechanisms, and in particular, major research initiatives were exploring every avenue to try to develop meaningful metrics for how the future climate would evolve under sustained CO2 forcing.

Okay, so one of the difficulties in having this debate is separating where the state of the science is today vs the pronouncements of activists, politicians, and lay people. It makes the debate much harder.

For example, in the past I was accused of using ‘fringe science’ whenever I quoted from a paper that deviated from the IPCC’s consensus. So, I made the conscious decision to accept the IPCC’s science and also use that as part of my argument. But then the IPCC’s projections became more conservative, and suddenly I was being told that the IPCC was ‘old science’ and that you had to read the latest papers to understand how dire the situation is.

Likewise, ‘peer review’ is the gold standard - until you offer up a peer-reviewed paper that in some way validates the ‘denialist’ side. Now suddenly the debate shifts to the motivations of the authors, whether the journal is legitimate, yada yada.

I’m perfectly happy to reference only the research accepted by the IPCC. Because if you actually dig into the science and look at the error bars around the estimates, you get a different picture than the alarmist one many activists present.

These metrics, today referred to as transient climate response and equilibrium climate sensitivity, are based on extensive studies of climate response in the paleoclimate, satellite data, the entire instrumental record, and a multitude of climate models eventually brought together in formal intercomparison experiments. The estimated values of these metrics were not influenced by the steep gradient of the late 20th century any more than they are influenced by the shallower gradient of the early 21st; indeed, the values have hardly changed at all.

My point about complex adaptive systems is that they evolve. Is the Paleoclimate at all useful in understanding the current one? I’m not sure, or at least I think the correlation is overstated. The correlation may work for some measures, while being totally wrong for others.

As an example, human population models were based on population models of other animals and of historical population growth. Those models extrapolated from what we knew about population growth and made predictions - which utterly failed. The thing about extrapolating the past into the future is that you never know where the inflection points are until they happen, and in complex systems there are many inflection points. Things move linearly until suddenly they don’t. Response curves suddenly move from linear to exponential, or vice versa. Or completely unexpected behaviors emerge that never emerged in the past. It’s a vexing problem.

Have you ever seen a functional MRI of the brain? The brain is another complex adaptive system. In theory, it should be much easier to understand the basic functioning of the brain than of the climate, because the brain can be instrumented, multiple brains can be used to find commonality of behavior and to create controls for experiments, etc. The brain operates on time scales that allow us to watch it work in detail as wer apply stimuli, and to repeat those experiments.

We know far more about the ‘nuts and bolts’ of brain chemistry and the way different parts communicate with each other than we do about the underlying mechanisms of the climate. And yet, when we finally developed the ability to see the patterns of neuron firing, we see something that looks completely chaotic and impenetrable. A stimuli will cause bursts of neuron firing, then suddenly a ‘wave’ of firings will propagate across the brain… Flashes of activity start and stop apparently randomly. We have no idea what these patterns are doing, because they are the ‘software’ of the mind and the mind is an evolved, massively parallel supercomputer and we don’t have the source code.

If we could see the climate system or an ecosystem or evolution itself on a time scale similar to the brain, and we could somehow instrument it so we could see all the communication pathways and feedbacks, we’d see something similar. Change something here, and you get a burst of activity somewhere else. Waves of information propagating throughout the system, causing it to mutate and change.

It’s very important to study this stuff, and climate models would be valuable even if we couldn’t predict future climate, because models are a great tool for hypothesis testing. It the long-term, multigenerational predictive value of those models that I question.

Not true at all, for at least three different reasons

1. We are not “cooling”, we have for a relatively short time been warming more slowly. New high-temperature records continue to be broken, so that weather effects that derive directly from elevated temperatures of land, air, and sea surface would still be operative. Indeed we appear to have seen this just this winter with the polar vortex and record-setting snow and cold deep in the US south; while no event is unambiguously attributable to climate change, this is consistent with accelerated Arctic warming.
2. Some extreme weather events may be attributable to net heat uptake increases rather than observed land-atmosphere temperature increases; for instance, circulation changes attributable to deep-ocean warming. Unless there is a negative change in the energy budget where the earth is for some reason retaining less heat and radiating more, these effects will continue.
3. The effects of climate forcing on weather are far from synchronous or immediate; they could take decades or even centuries to manifest themselves.

I understand all that. My point was that you can’t point to a specific weather event and say, ‘That’s because of global warming’, or even "that’s stronger than it would otherwise be because of global warming’. And my further point was that if we happen to be in a period of very localized cooling purely due to randomness, it makes it even harder to blame specific weather on warming.

But I think we both agree that short term weather events should not be used as proof for or against global warming. A few years of cooling doesn’t really mean anything, and a year of higher or lower than average storm activity is also meaningless in the context of the larger debate.

The claim of some kind of generic “stability” is true geologically and on geologic timeframes, but entirely without basis when dealing with any existing climate regime and ecosystem. The simple way of restating that is that the planet will survive just fine, no one is worried about it, but push the climate hard enough and humanity may not; or at least, more realistically, may suffer major privations in loss of life and property and quality of life.

I already corrected myself to say I was really talking about metastability. I’m totally cool with the notion of tipping points and failure cascades. It could happen. I believe the climate is stable to minor inputs on geologic timeframes, but it could still get mighty uncomfortable for humans in a shorter time frame.

Still, even in the last 50,000 years there have been some pretty big shocks to the climate system, and it seems to keep trucking along through a fairly narrow range of temperatures. Going back further, even massive events like extinction-level impacts didn’t cause the climate system to go completely out of control. I have to believe it’s fairly robust.

I really bristle at the kinds of broad generalizations about self-stabilizing systems that are sometimes uttered because that’s just not how the climate system works. Possibly the closest event in the paleoclimate comparable to what is happening today is the Paleocene-Eocene Thermal Maximum. The carbon release rate at that time was at least an order of magnitude less than what it is today even at its peak, and it was an event that transformed all life on earth.

And yet, here we are with an order of magnitude larger carbon release rate, with nary an extinction in sight. Now, maybe that will happen over a longer timeframe, but maybe it won’t. Again, the climate system today is not the same one that existed in the Paleocene, and extrapolations of that system’s behavior need to be carefully weighted.

Humanity came into existence during the modern ice age cycles, and civilization during the last few millennia of the Holocene. At no point in the only world we have ever lived in has CO2 been anywhere outside the range of 180ppm during an ice age and 280-300ppm during an interglacial. It has now soared more above the interglacial maximum than the entire differential between ice ages.

While true, and certainly a factor that should give us pause, it’s really meaningless by itself. I’m sure we can find lots of measures of things that are at all-time highs or lows, yet kind of irrelevant. I will accept that having a CO2 excursion outside of historical norms means we can’t take the historical stability of climate for granted going into the future.

But one thing you also have to remember when throwing around comparisons like that is that climate response to CO2 is not linear, and neither is the re-uptake rate. Increases in CO2 have diminishing effect, and the re-uptake rate increases as well. That doesn’t mean we can ignore it, but it does mean that 400 ppm is not twice as bad as 200ppm.

Far from taking comfort in some generic euphamisms about self-stabilizing systems, we should be concerned about this entirely new climate era we are in, this uncontrolled experiment that is quickly taking us outside the adaptive capacity of the species that make up our ecosystem and have the potential to radically disrupt global circulation systems.

That’s a fair argument, and it’s similar to the precautionary principle - we’re making changes we don’t understand to a climate system we rely on and which we also don’t understand. That carries risk.

Unfortunately, it’s hard to sway public opinion and generate political action based on nebulous risks. So the AGW movement goes farther and starts making sweeping claims about our certain knowledge of a horrible future to come unless we act now, and then treats anyone who questions this as a heretic to be expelled from civilized debate because the science is ‘settled’.

Indeed it’s more than just continuous changes we need to be worried about. Albedo changes from melting polar ice and methane releases from both land and ocean are likely to accelerate the feedbacks; there is as much as 1800 GT of carbon locked up in Arctic permafrost and similar amounts in methane hydrates in the now-warming oceans.

I’m not convinced we understand the albedo change mechanism. It seems to me to be just as likely that before the poles melt and the methane is released the increase in water vapor will trigger an increase in cloud formation that will reduce the amount of solar forcing. Or that an increase in moisture will result in more snowfall in cold climates. Or that the additional heat will be sequestered in the ocean for a long time. Or that it will cause some other negative feedback. We just don’t know at this point - certainly not well enough to make the kinds of specific predictions some AGW activists make.

At some point both the ecosystem and the physical climate system reach tipping points; this is how these systems behave. Hans Oeschger was the first to recognize tipping points as the now acknowledged characteristic behavior of climate systems, and Anthony Barnosky and others have made a similar case for biological tipping points.

But that’s not very helpful unless we know where those tipping points are. Fear of an unknown but possible tipping point could justify preventing any man-made change. Fracking? Hell, maybe there’s a tipping point at which major earthquakes will be triggered. Population growth? Maybe there’s a tipping point where suddenly a cascade will cause massive famine.

Preventing economic activity carries real costs, both financially and in terms of human life. You can’t stop it based on fears of cataclysmic change if you don’t know where the cataclysm is, when it will happen, or what it will take to get there.

Read any conservative financial blog, and you’ll see the same arguments you’re using, except against the government. We’re in new regimes never before seen in terms of debt, money printing, and other intrusions in the economy. We’re headed for a tipping point which will cause a global economic collapse, unless we stop what we’re doing right now, shrink the size of government, eliminate the deficit, etc. And hell, they even have plenty of historical examples of such tipping points to prove their case. But the same people arguing for CO2 restriction because of such an unknown risk completely discount it when it comes to government spending. How come?

I can’t help but feel that you’re confusing climate scientists with Greenpeace activists, and the practice of climate science with the exercise of backroom political campaigns.

As I said above, it’s hard in these debates to stay limited to the science. I’m affected by it too - I can’t count the number of times I’ve brought up a point from the IPCC and tried to talk about it scientifically, only to have the ‘other side’ come back with a strawman argument refuting something some idiot Republican political hack in Congress had to say about global warming. Both sides tend to go after the easy targets and avoid the hard ones.

The scientific method and its processes are no different in climate science – which is in any case an interdisciplinary field – than they are in any other field of science. It’s replete with scientific skepticism and reticence to state conclusions without incontrovertible evidence, and you see this all the time in the legitimate journals. The consensus-driven IPCC is even more conservative, and they manage to say anything at all only because the evidence is pretty much overwhelming on the key issues.

There is a real debate going on today about how the scientific method applies to the study of complex systems. How ‘scientific’ is it when you can’t falsify results, replicate results, compare hypotheses against controls, and when the system you are studying by its nature does not lend itself to scientific reductionism?

Back in the 20th century when science was in its popular heyday and scientists were heroes, every discipline wanted to be ‘scientific’. But just because you have lots of numbers and can do math on them doesn’t mean you’re being scientific. Is macroeconomics a science? Or is it philosophy? How about psychology? You can do experiments in psychology and build models and collect data through surveys and cognitive tests and such, but if you look at the state of psychology it actually hasn’t improved much in a long time. You can give a survey to a thousand respondents and get enough data to generate some truly impressive P values in your regression analysis, but sometimes that’s irrelevant because the surveys themselves were riddled with errors or bias the outcome, or the thing they measured was irrelevant.

Not so much in the denialist shadow press, where the authors do the rounds of conservative media and denialist web sites and lie about the meaning of their papers. Like Nic Lewis, who had a minor role in a minor NatGeo research letter that tentatively suggested possible new constraints on transient climate response. Lewis immediately went on the denialist virtual talk show circuit to proclaim a revolution in climate science. I don’t see real climate scientists doing that, particularly the lying part. For one thing, they don’t really have time, and for another, they have actual reputations.

I have no knowledge of the particular case you’re talking about, but I’ve seen many climate scientists make pronouncements about future damage from AGW that are not justified by the underlying research. But again, it’s hard to separate the climate scientists from the activists - especially when the media itself doesn’t draw a clear distinction.