Bishop Hill Buckle up
Oct 14, 2013 Climate: Models Climate: Surface Climate: sensitivity 
During the Energy and Climate Change Committee hearing last week, Peter Lilley asked the men from the Climate Change Committee what evidence would cause them to change their minds about global warming, a question that was fairly studiously avoided. Interestingly, Simon Buckle of the Grantham Institute has written to the FT (not online) to suggest what the reply should have been:
As a physicist, I would modify my view that we are conducting a dangerous experiment with the Earth’s climate if one or both of the following hypotheses were strongly supported by evidence.
First, the identification of a major new process in the climate system that significantly and robustly, over time, moderated the effects of greenhouse gas emissions. At one point, cloud responses to climate change were thought to be a contender for such a “negative feedback” mechanism. Sadly, observations do not support this.
Second, if the timescale of change was much longer than we currently think. We could then perhaps take a century or two to make a transition to a low-carbon economy, instead of perhaps half a century. However, the unprecedented pace of change does not suggest we live in such a world.
While Buckle presents two different scenarios, it seems to me that in fact the two are identical. The only thing that could make the timescale of change much longer is a moderating mechanism of some kind, one that hadn't previously been included in the models. But Buckle is completely wrong to suggest that this mechanism needs to be identified. The models, and the hypothesis of rapid warming, can be falsified quite happily without knowing what factor is responsible. This is the scientific method after all.
Once that uncomfortable fact is taken on board it becomes clear that Buckle should already be questioning his position on global warming. But, not unexpectedly, he concludes that "Extremely well-established physics principles suggest that surface warming will resume and then proceed at a rapid rate". In other words "But the greenhouse effect".
Put in those terms, it becomes clear just how thin his argument is.
Reader Comments (121)
As a physicist they should know is for those making the claim to 'prove' it not for others to disprove it. Any student doing A level science is taught that.
Another basic science fail for climate ‘science’, and they wonder why people don’t just ‘trust them’
Paul Dennis
Thanks for acknowledging your teachers (I'm not one, or related or anything, BTW). But many of us have a teacher or two who made a big difference, and for the pedagogues out there, it is important to acknowledge them.
In fact, you've inspired me to start a Discussion thread!
Simon - I am not confused about this, I just didn't explain it clearly enough, for the sake of brevity. Yes the clouds are not warmer, and they only moderate the heat loss at night. But in so doing so they effectively have a warming effect in that they are impeding energy which would be lost to space, if there were clear skies. So more night time clouds are a positive feedback. But more daytime clouds are clearly a negative feedback, and the latter dwarfs the former, hence net cooling and net negative feedback (unless you are an IPCC group-thinker like EM of course).
Maybe the heat went to one of these 11 alternate universes that string theory depends on.
lapogus Oct 15 9:15 AM "[clouds] have a warming effect"
Maybe the problem is that warm and cool are relative terms. However a "positive warming effect" (your earlier comment) implies a gradually increasing temperature, potentially measurable. Since the sun doesn't shine at night what else can produce such an effect?
lapogus
Brief, concise and clear.
" Understand, however, that the basic physics of CO2 says a
doubling only results in ~1C warming,"
Oct 14, 2013 at 10:29 PM Rob Burton asks
as has been asked many times before by several people where is the basic Physics explanation written down for this??"
Rob, The basic physics of CO2 would say that with the average composition of outgoing radiation, the extra amount of that radiation absorbed by CO2 and retransmitted back to the surface is the equivalent of increasing the temperature of the surface by 1 deg to give more outward boltzmann radiation and balance the energy flux. It says nothing about what would actually happen eg more evaporation reducing the effective temperature, cloud changes because of more evaporation it's just a theoretical analysis of one physical property in amongst a myriad of other mechanisms in a chaotic system. The most that the physics of CO2 is really saying is that there is a specific theoretical increase in back radiation (about 5 watts /M^2 if my memory serves me well).
entropic man (Oct 15, 2013 at 1:47 AM) said "Incidentally, here's another paper for the spin sceptics to "debunk"".
Well, it didn't take long for someone to have a go...
http://wattsupwiththat.com/2013/10/15/will-global-warming-increase-the-intensity-of-el-nino/
SandyS Oct 15 20:13 "lapogus Brief, concise and clear"
Fraid not. lapogus still tries to clarify his use of the ambiguous word "warming" instead of using a phrase like "less rapid cooling" which would make it quite clear that at night temperatures continue to drop relentlessly until dawn. (Absent that is any complicating factor such as the passage of a warm front).
Stuck Record,
How would one prove that faeries do not exist?
@ Breath of Fresh Air
The current goalpost is 30 years (well maybe as you can never get a straight answer) so 30-13=17 more years before they question the theory
Not even then. In 17 years' time, after 17 more years of fiddling with the data, the past will have been made colder.
@ Osseo
you maintain that putting twice the amount of water in isn't a 'mechanism'. I say it is a way of making the kettle boil slower.
Increasing the amount of coolant in my car's engine is a very good way of delaying the onset of overheating. Hairsplitting over whether this a mechanism or not is what a dodgy garage would do when justifying having overcharged me for doing it.
"It is difficult to get a man to understand something, when his salary depends upon his not understanding it"
Simon - I see why you think it is ambiguous, but if a night-time cloud passes over and say reduces the cooling rate, then the net result is that the dawn temperature will be less cold (i.e. it will be warmer) than it would have been if there had been no cloud at all. But maybe you are right, as I have no problem with saying that clouds at night time have a positive feedback, by slowing the rate of cooling. The reason I was content to use the warming word, is because it was in the context of the diurnal (and seasonal) factor.. Daytime clouds reflect sunlight and effectively keep surface temperatures cooler than they would be. And at night clouds impede surface cooling and effectively keep surface temperatures warmer than they would be. (whoops, I have said it again). As the energy from sunlight reflected by clouds is of a much greater magnitude than the energy impeded by night time clouds, it seems obvious that more cloud cover (resulting from more water vapour, resulting from higher atmospheric temperatures, allegedly resulting from higher atmospheric CO2 levels) is a net negative feedback. Shall we just agree to disagree?
http://wattsupwiththat.com/2013/06/20/model-data-comparison-daily-maximum-and-minimum-temperatures-and-diurnal-temperature-range-dtr/
lapogus/Simon, FWIW the above link is quite an interesting take on what has been happening with diurnal temperatures and the changing affect on global average temperature anomoly. The usual view is that Tmin grows more quickly than Tmax as a fingerprint of AGW but it's been the other way around for the last 25 years or so.
lapogus Oct 15 1:42 PM
lapogus mon brave, we do NOT disagree.
It's just that from my pov the (shall I say injudicious) use of the word "warming" has regrettably succeeded in conferring an altogether spurious legitimacy on the concept of "downwelling radiation" as a physical reality rather than recognising it as merely a useful fiction in an energy accounting exercise.
And as I've said to myself many times "neither does the Thermos Flask WARM the coffee, nor a blanket the corpse". Best, simon
yes global mean temperature is a dull instrument very much like those that hijacked it
simon abingdon
Ok good point.
@ Oct 15, 2013 at 3:21 PM | Dolphinlegs,
Good point.
Simon Abingdon's comment above regarding Thermos flasks reminds me of one of my favourite jokes.
David Beckham is being showe a Thermos flask, and it is being explained that it will keep coffee warm or iced water cold.
DB says "That's really clever. How does it know which is which?"
Simon Abingdon.
Downwelling radiation exists. Take a basic £10 infrared thermometer outside and point it at a clear night sky. The temperature reading is due to the downwelling radiation. Borrow an infrared spectrometer from your local university physics department and you can measure intensity and spectrum. It peaks around 13 micrometres, the main emission wavelength for CO2.
I'm alarmed that you deny the existance of a phenomenon which is easily detected, measured, and, at a number of sites, monitored.
Thank you for nice information