“Logically, for a claim of observations being ‘consistent with’ model predictions to have any meaning then there also must be some class of
observations that are “inconsistent with” model predictions.”

Though I agree there’s a risk (and examples) of attributing too much to AGW, there are spatial and temporal patterns in the climate which are consistent with warming due to addition of GHGs, and *inconsistent* with other processes which might have caused decadal-scale warming, esp. the trend from the ca. 1960s to ca. 2000.

First, there’s the stratospheric cooling trend, due a combination of tropospheric GHG buildup and stratospheric ozone depletion. Surface warming driven by aerosol reduction would not be accompanied by stratospheric cooling.

Second, there’s the temporal pattern of surface change through the 20th Century. This pattern, especially the warming in the latter ~ 40
years, is inconsistent with forcing by aerosols, volcanic activity, and solar variability by themselves, and can only be reproduced when
these forcings are combined with GHGs.

Finally, IPCC AR4 shows data from daytime/nighttime temperatures saying there was a decrease in cold nights and increase in warm nights over three intervals 1901-1950, 1951-1978, and 1979-2003. This pattern of diurnal temperature change seems to me to be another fingerprint of
GHG-driven warming and inconsistent with other forcings.

Of course I suppose it’s always possible there are other still-undiscovered forcings which would give rise to these patterns, and/or they arise from natural variability.

But it would seem that these “fingerprints” constitute a class of observables which could provide falsification of at least some hypothesized forcings.

Posted by: WHoward

Though I agree there’s a risk (and examples) of attributing too much to AGW, there are spatial and temporal patterns in the climate which are consistent with warming due to addition of GHGs, and *inconsistent* with other processes which might have caused decadal-scale warming, esp. the trend from the ca. 1960s to ca. 2000.

First, there’s the stratospheric cooling trend, due a combination of tropospheric GHG buildup and stratospheric ozone depletion. Surface warming driven by aerosol reduction would not be accompanied by stratospheric cooling.

Second, there’s the temporal pattern of surface change through the 20th Century. This pattern, especially the warming in the latter ~ 40 years, is inconsistent with forcing by aerosols, volcanic activity, and solar variability by themselves, and can only be reproduced when these forcings are combined with GHGs.

Finally, IPCC AR4 shows data from daytime/nighttime temperatures saying there was a decrease in cold nights and increase in warm nights over three intervals 1901-1950, 1951-1978, and 1979-2003. This pattern of diurnal temperature change seems to me to be another fingerprint of GHG-driven warming and inconsistent with other forcings.

Of course I suppose it’s always possible there are other still-undiscovered forcings which would give rise to these patterns, and/or they arise from natural variability.

But it would seem to these “fingerprints” constitute a class of observables which could provide falsification of at least some hypothesized forcings.

You expressed an idea that is very popular these days, but has always perplexed me. You wrote: “I tend to be rather leery about seeing the governments as in this case artificially manufacturing a crisis here.” Why? The nastier side of human history is nothing but governments artificially manufacturing a crisis of one kind or another, in order to extract certain behaviors or wealth from the populace. Every despot starts by adopting a ‘noble cause’ then exaggerates the threat to that cause, making a crisis. The last two administrations, though not despotic, have resorted to similar behaviors quite often; Bush on Iraq and Clinton on a series of social issues, each issue proclaimed to be a crisis, requiring immediate action. Perhaps because the behavior is so common, people don’t recognize it.

On the other hand, private companies and corporations are often guilty of using persuasion to get individuals to buy their products and services, but rarely does this rise to the same level that is almost routine in world governments.

Preventing an AGW crisis would certainly be a noble cause if the threat was well established, but it isn’t. Exaggeration of the threat has been routine since the beginning, with constant attention to the direst scenarios, no matter how unlikely. The hostile treatment of those offering a different view is also a clue to what is happening. The consensus view has shut out hundreds of scientists with a different viewpoint, ignoring their evidence and restricting their resources. When these scientists turn to alternate sources to get their message out, they are further vilified by those who forced them to do it. (I am not talking about the scientific community per se, although they are compliant. I am talking about the political and environmental community that is pushing the issue.)

You can be leery about governments artificially manufacturing a crisis if you want to, but it is SOP most of the time. And while governments can force compliance regardless of the will of the individual, private corporations can only survive by pleasing their customers. While I do not have complete trust in either entity, it is the work of government that has earned the lion’s share of my skepticism.

Furthermore, sweeping conclusions are being made on precious little data and rather large assumptions. Amazingly, we are asked to believe that steadily increasing CO2 and fluctuating amounts of ozone depletion always add up to no change in temperature year after year. One could marvel at this amazing coincidence or one could question whether or not these factors have any real influence at all. I think the latter would be wiser.

You wrote: “…my concern is that historically science has been ill-served when outside vested private and ideological interests become too entangled in the discourse.”

I would agree completely, but then you single out right wing think tanks and the fossil fuel industry as examples of said ‘interests’. In the debate on climate change, these organizations spend less than a few percent of all the monies involved in the debate. Do you think that governments have no vested interest in promoting another crisis, for reasons that have nothing to do with the advancement of science? Do you think that universities, where most of the research is done, have no vested interest in keeping the climate crisis alive and well, for reasons that have nothing to do with the advancement of science? If man-made global warming is shown to be a non-issue, governments will lose power and universities will lose face, not to mention millions annually in grant monies.

There are ‘vested interests’ on all sides and even in the peer-review process, largely controlled by academics and government employees. I don’t mind you questioning the motivation of right wing think tanks and oil companies, but the real power and motivation to corrupt the science exists in government funding and academic control of the research.

Ultimately, one must return to the science itself and determine which hypothesis explains the observations the best. The AGW/IPCC hypothesis doesn’t even come close to being the top contender.

One final note: You wrote the phrase “When fossil fuel industries and right wing think tanks become key foundations for much anti global warming research…” Does that mean that the vast majority of research into climate change is PRO global warming? Hmmmm

The lack of decadal predictive skill is even more acute with regard to regional climates. No climate modeler disputes this in private. These limitations are the reason modelers squirm when asked to issue straightforward, verifiable predictions. Furthermore, many modelers also understand (but most are loathed to admit), that the lack of annual to decadal predictive skill also portends a lack of skill for longer term multi-decadal forecasts. It is a scientific absurdity to maintain that small changes in boundary values will somehow impart more forecast skill if one moves far enough out in time. The so-called prediction “sweet spot” is a completely untested hypothesis that is very likely mathematically untenable. The only way around this conundrum for the modeler is to make multi-decadal forecasts or projections which are so vague, as to render them practically meaningless. They say things like: “Models show warming of 1.5 to 5 C, for a doubling of C02 if run out over multi-decadal to century time spans.” For a prediction such as this, no real-world observation is inconsistent, because there is never really anything in the original statement but smoke and mirrors. If one makes the observation that over 10-20 years, mean global temperature is not rising, the apologist can always say, in the models, warming comes back with a vengeance just over the horizon. In this way, the beauty is always in the eye of the beholder. It is indeed a big Wizard of Oz machine. For those who choose to believe in the wizard, he is always right.
So Roger, you will not receive an answer to your question. To a climate modeler, your question is not well posed. I suspect you realize this however, and are rather using this argument to educate an otherwise uniformed public about what is really taking place here. If one can provoke these guys enough, they have two options. The first option might be to fess up about the limitations of what models are, and what they offer us in learning how the actual climate system works. The second option is to push the envelope and press onward to produce a forecast. Public demand for a forecast, I suspect, is exactly what has motivated the issuance of the new forecast in the recent Nature paper. The wizard has finally felt forced to do a trick. We will see how he does. In my opinion however, it is better for these guys to fess up clearly and publically now, and tell us precisely what they can and cannot predict with skill, rather than oversell them now, only later to lose face with the public. I believe that many modelers fear that if the public were fully educated about these forecasting limitations, it might inevitably lead to what many believe would be bad economic and energy policy decisions.

Roger has been called a ‘denier’ or a ‘delayer’ for pointing out the scale of the problem regarding global CO2 emission reductions, and for testing IPCC sea level and temperature projections.

That said, the IPCC have climate got sensitivity for a doubling of CO2 well covered by a range of 1.1C to 6.4C for their modelled scenarios. Personally, I’d say 1.1C was the nearest to reality, and no one has published a definitive, proven sensitivity.

Recently, we have seen the emergence of new decadal models with much shorter term projections i.e. Smith et al (2007) who say natural climate variations will dampen the effects of man-made CO2 up to 2009, followed by at least half of the years between 2009 and 2014 exceeding the existing temperature record (1998), with a 0.3C warming by 2014.

Now we have a new computer model developed by German researchers, reported in the journal Nature (2008), suggesting that the Earth’s temperature may stay roughly the same for a decade, as natural climate cycles enter a cooling phase, to about 2015. However, temperatures will again be rising quickly by about 2020.

So, we have a couple of new model projections that both include natural cooling factors, but one says non-warming up to 2009, the other to at least 2015 to 2020.

We can test these models against observations without having to wait too long.

We also have Kerry Emanuel reconsidering the strength of the relationship between global warming and hurricane intensity. For Atlantic hurricanes, two of the seven model simulations Emanuel ran suggested that the overall intensity of storms would decline. Five models suggested a modest increase.

With so many models, giving such a range of projections – it’s difficult or impossible to falsify them all.

Furthermore, models can’t hope to replicate the complex climate system, which is far from fully understood – they are particularly poor where clouds are concerned, and at making predictions for the likes of ENSO and PDO.

Then we have the model for greenhouse warming itself, which predicts amplified Lower Troposphere warming compared to the surface, particularly in the tropics, and Stratospheric cooling (due to CO2 rather than Ozone). There is evidence that this model is falsified, particularly in the case of the tropical Lower Troposphere warming, or lack of it.

Models are useful diagnostic tools, but I wouldn’t stake my future on model projections that can’t be verified.

NASA GISS clearly laid out their methodology and reasons for arguing that Antarctic climate patterns are related to the ozone hole, in a manner that does not seem over the edge. If there are reasons for skepticism about this they should certainly be part of the scientific discourse on this topic as long as they are based on scientific methodology and not name calling. Let peer review take its course. To paraphrase Lord Acton, peer review may not be perfect, its just that all other systems are worse.

As a political scientist rather than a climate scientist, interested in policy making and negotiations under conditions of uncertainty and possibly irreversible consequences, my concern is that historically science has been ill-served when outside vested private and ideological interests become too entangled in the discourse. From Gallileo to Lysenko, to tobacco and pharmaceuticals. When fossil fuel industries and right wing think tanks become key foundations for much anti global warming research, my first reaction tends to be one of deja vous all over again.

mb

Let me add one additional fact to Jim Clarke’s comments (with which I agree).

Warming due to co2 is a log function. Thus since co2 is increasing linearly (roughly, it’s not increasing exponentially) future warming due to co2 will be less than we have seen in the past. Thus we get the benefits of co2 fertilization for the biosphere and modest warming.

Let me add one additional fact to Jim Clarke’s comments (with which I agree).

Warming due to co2 is a log function. Thus since co2 is increasing linearly (roughly, it’s not increasing exponentially) future warming due to co2 will be less than we have seen in the past. Thus we get the benefits of co2 fertilization for the biosphere and modest warming.