I’m always searching for better and simpler ways to explain the reason why I believe climate researchers have overestimated the sensitivity of our climate system to increasing carbon dioxide concentrations in the atmosphere.
What follows is a somewhat different take than I’ve used in the past. In the following cartoon, I’ve illustrated 2 different ways to interpret a hypothetical (but realistic) set of satellite observations that indicate (1) warming of 1 degree C in global average temperature, accompanied by (2) an increase of 1 Watt per sq. meter of extra radiant energy lost by the Earth to space.
The ‘consensus’ IPCC view, on the left, would be that the 1 deg. C increase in temperature was the cause of the 1 Watt increase in the Earth’s cooling rate. If true, that would mean that a doubling of atmospheric carbon dioxide by late in this century (a 4 Watt decrease in the Earth’s ability to cool) would eventually lead to 4 deg. C of global warming. Not good news.
But those who interpret satellite data in this way are being sloppy. For instance, they never bother to investigate exactly WHY the warming occurred in the first place. As shown on the right, natural cloud variations can do the job quite nicely. To get a net 1 Watt of extra loss you can (for instance) have a gain of 2 Watts of forcing from the cloud change causing the 1 deg. C of warming, and then a resulting feedback response to that warming of an extra 3 Watts.
The net result still ends up being a loss of 1 extra Watt, but in this scenario, a doubling of CO2 would cause little more than 1 deg. C of warming since the Earth is so much more efficient at cooling itself in response to a temperature increase.
Of course, you can choose other combinations of forcing and feedback, and end up deducing just about any amount of future warming you want. Note that the major uncertainty here is what caused the warming in the first place. Without knowing that, there is no way to know how sensitive the climate system is.
And that lack of knowledge has a very interesting consequence. If there is some forcing you are not aware of, you WILL end up overestimating climate sensitivity. In this business, the less you know about how the climate system works, the more fragile the climate system looks to you. This is why I spend so much time trying to separately identify cause (forcing) and effect (feedback) in our satellite measurements of natural climate variability.
As a result of this inherent uncertainty regarding causation, climate modelers are free to tune their models to produce just about any amount of global warming they want to. It will be difficult to prove them wrong, since there is as yet no unambiguous interpretation of the satellite data in this regard. They can simply assert that there are no natural causes of climate change, and as a result they will conclude that our climate system is precariously balanced on a knife edge. The two go hand-in-hand.
Their science thus enters the realm of faith. Of course, there is always an element of faith in scientific inquiry. Unfortunately, in the arena of climate research the level of faith is unusually high, and I get the impression most researchers are not even aware of its existence.
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How do the satellites and model cope with background cosmic ray radiation? We know this is modulated by the solar wind (it is currently very high right now up 40% in the last few years) and is equivalent overall to a background temperature of 3 degrees.
If 3 degrees from space is equivalent to an extra 3 watts that the earth receives and that what the earth receives is varying by 40% in just a few years then this has got to be a significant part of the radiative balance (on aprevious post Dr Spencer showed a light extra energy gain of 1 watt over a period of a decade as measured by CERES “radiative balance” satellite)
Can anyone help?
Roy,
This is far from clear to me, I have to say. And I am not new to this!
I thought IPCC were saying they do KNOW the cause – it is the ability of the extra carbon dioxide to radiatively force the temperature in the atmosphere. Their preferred computer models calculate an extra roughly 2.5 watts/sq metre so far. This had led to about 1C degree rise since 1900. They don’t say ALL of that is extra greenhouse gases, but that MOST of it is. They don’t specify a figure for that ‘most’ but of course they have to mean more than 50%.
They regard cloud change data during this period as problematic – including the 4% decline over 1980-2000 measured by the International Satellite Cloud Climatology Project, and hence draw no conclusions at all, simply regarding any cloud changes as ‘feedback’ and hence a consequence of the extra greenhouse gases.
I raised these issues in my book – including details of NASA’s GISS data sets that showed extra SW radiation penetrating to the Earth’s surface throughout the warming period from 1980 to 2000, and then falling after 2001. NASA suggest these changes are due to cloud variability. Work at the Big Bear Solar Observatory on measuring ‘earthshine’ and albedo (reflected light from the earth to the moon) essentially confirms the changes in cloud and the rather large watts/sq metre compared to the RF from carbon dioxide (I reckoned about 4:1 at least).
Specialists at NASA as recent as 2008 (Takmeng Wong for example) were clear that the warming was driven by the clouds, but that a) this could be a natural cloud cycle, or b) a feedback from ‘global warming’.
Since 80% of global warming according to IPCC is held within the oceans, and 70% of the surface is water, I have never managed to understand how carbon dioxide warms the oceans significantly, compared to the large pulses of SW radiation.
The whole story does not stack up – but Roy, I am no physicist and this graphic does not help me at all! isn’t the short answer that – as Kevin Trenberth so eloquently put it in the ‘climategate’ files, when trying to work out where all the heat had gone – ‘we can’t account for it, and its a travesty that we can’t’. I think he meant that it was a travesty considering all the money and technology that had already been thrown at the problem.
Phillip Bratby and those supporting his arguments have a point, but they are overstating it. While is certainly true that the omnipresence of microclimates limits the value of assessing a “global” climate, there nevertheless are global variables in Earth’s overall climate. For example, changes in toatal solar energy flux or solar magnetic flux might have effects on every part of the Earth—even if those effects are of differing magnitudes in the various microclimates. By averaging temperature measurements from many different microclimates and watching for change over time with positive correlations, one can find true signals amidst the noise. Those signals will then give information on the variables that to some extent effect most or all of the microclimates. Issues related to greenhouse gases, aerosols, solar variables, galactic cosmic rays, net global cloud cover, wobbles in the Earth’s rotation or skewing of the Earth’s solar orbit, or changes in the density of dust in our interplanetary space as our sun moves through its galactic orbit are all examples of variables that could be studied in relation to an averaged global temperature.
KW
John Finn (02:17:12) :
You hit that one out of the ballpark.
The lake, in this case, is the world’s oceans.
Cement a friend. I agree. To my knowledge, “forcing” is not a term that was used in physics until “climate scientists” invented it to bamboozle people. I have never been able to reconcile the Kiehl & Trenberth paper on the Earth’s Annual Global Mean Energy Budget. And Climategate has revealed that neither could they – in Trenberth’s own words “we are not close to balancing the energy budget”.
Downwelling or back radiation anyone???
Peter Taylor (07:34:25) :
Perhaps the heat has gone out in radiation, as indicated by an Earthshine effect on the Moon noted to have risen dramatically the past few years.
[Project Earthshine shows increased albedo since 1998. RT – Mod]
“Peter Taylor (07:34:25) :
[…]
I think he meant that it was a travesty considering all the money and technology that had already been thrown at the problem.”
Don’t forget the brains thrown at it.
Doug S (06:50:18)
I replied to this but something happened with the preview and backspace and it disappeared.
Check my post above for a description of how the CO2 behaves and think what ppm means. There are lots and lots of other molecules in the clumps that pick up the softer photons and turn them finally into kinetic energy.
All this is happening at electromagnetic time constants, much less than a second, so my guess is that frequency analysis would not help. It is a steady state which changes slowly with daytime and winds etc.
“Note that the major uncertainty here is what caused the warming in the first place. Without knowing that, there is no way to know how sensitive the climate system is.”
By deleting the major cause for the warming a priorì there is no way to understand climate change at all. Unless the hyperesoteric radiation gets discovered (it won’t, simply because I coined this theory first).
Jeremy.
Those 3 deg is equivalent to 4.5 microwatt, 3^4*5.678*10^-8
lgl (08:11:42) :
Jeremy. Those 3 deg is equivalent to 4.5 microwatt, 3^4*5.678*10^-8
Talking about very small energy fluxes: the solar wind gives us 250 microwatt/m2
anna v (07:59:28) :
Thanks anna. There’s a lot to learn here (for me anyway) and based on the comments of people much smarter than me, the science seems far from settled.
RR Kampen,
Have you managed any ice skating on the canals this winter?
Cement a friend (07:00:27) :
With surface temperatures around 50C forced convection with winds over 20km/hr exceeds radiation. Just think about washing drying on a windy but overcast day.
I’ve never heard of anyone on this planet drying their washing in 50ºC (122ºF) on an overcast day!
Unfortunately, in the arena of climate research the level of faith is unusually high, and I get the impression most researchers are not even aware of its existence.
True. Largely because the science has been molded to fit the faith. The faith suggests we can achieve mass behavior change by uniting against calamity. But if the calamity is a fabricated dragon living on the outskirts of town, faith is misplaced. It relies on belief that misbehavior, questioning orthodoxy, in-dependence, cause the dragon to breathe fire on the cowering town folk.
The problem here is the science – once discernible by a very few, is now accessible to many. And many now see behind the curtain. No intelligent man wants to be bamboozled by myth. Especially when it costs him the fruits of his labor. The lesson learned is that faith manipulating truth does not work. Truth comes first, and faith lifts it up.
A model using data from Mauna Loa for CO2, and satellite temperature data shows that temperature changes seem to be related to the rate of change of the CO2 level, not the absolute level. This explains why we are seeing cooling now, but implies that we well see a return to warming when the economic recovery starts.
The model is shown at: http://www.2bc3.com/warming.html
imapopulist (05:57:24) :
“By their nature models will reflect the biases of those who prepare them. ”
Indeed you would have some suprising allies on your incisive statement:
source
(PDF)
————
As for uncertainties in the minds of the modellers see:
http://www.eastangliaemails.com/emails.php?eid=1052&filename=1255523796.txt
Nice lucid post.
There is very little one seems to know a priori about the climate system. But I have always scratched my head about the implausibility of a climate system that is close to instabiltiy with respect to CO2 concentration. The IPCC asserts that the climate sensitivity is in the range 2-4.5 deg C for doubling, with about 3 degrees as the most likely value. Then the dimensionless feedback factor must be between about 0.5 and 0.8 (0.67 most likely), with 1.0 being unstable. What we know about the history of the earth’s climate does not seem to support this. Rather the climate seems to have been stable with respect to changes in GHGs.
Oh ye of little faith. The good book of AR-4, Chapter 9, verse 9.4.1.2 tells us “The fact that climate models are only able to reproduce
observed global mean temperature changes over the 20th century
when they include anthropogenic forcings, and that they fail to
do so when they exclude anthropogenic forcings, is evidence
for the infl uence of humans on global climate.”
Can ye not also see how this warming is unprecedented in the vision inspired figure 9.4 as ye heretics sometimes describe as the hockey stick?
Repent and embrace the AGW truth!
Leif,
Thanks for the clarification – those flux rates are indeed negligible.
I just find it confusing that we speak of background cosmic radiation as being “3 degrees” and yet a radiative balance energy flux gain of 1 watt per square meter for earth surface is of the similar order of magnitude as 1 degree of surface temperature of black body earth.
Why the six orders of magnitude difference?
Jeremy (10:07:26) :
Why the six orders of magnitude difference?
Because the temperature to use in the Stefan-Boltzmann law is the ‘absolute’ temperature [degrees Kelvin]= 273+temp in Centigrade.
The 3 [closer to 2.725] degree cosmic microwave background is already Kelvin, K, but the 3 degree temperature change is from 288K to 291K, and the flux change is thus proportional to (291^4-288^4) ~ 291 million compared to 2.725^4 ~ 55 or 5 million times smaller.
I see a lot of comments regarding the average global temperature. I think there is a fundamental misunderstanding of why this metric is used. The following is my understanding of its usage – but I am no expert or scientist, just an electrical engineer. If my explanation is wanting, then I welcome a correction from those more knowledge.
We hear very often “weather is not climate”. This is true because weather is an instataneous measure of certain atmospheric phenomenom, and climate is a stastical calculation of the history of those weather measurements.
Thus, climate is math – statistics to be exact. That is why the work of Steve McIntyre is so important. Steve is not a climate scientist, but he is something far more important – a statistician. It is why he has been able to poke so many holes in the IPCC and CRU climate data; he can show where the statistics are wanting, and thus the climate representations are also wanting.
The same holds true for climate forecasts. These forecasts are statistical in nature: i.e., they are a probability of occurrence. This is why a cold winter, like the Northern Hemisphere is experiencing now, does not necessarily invalidate the warmists climate forecasts. This winter is a data point in the statistical calculation, not the whole data set.
This brings us to global average temperatures. As a weather number, global average temperatures are worthless. However, since climate is statistics, it has mathematical meaning. It shows a trend, not an occurrence.
Well, that exhausts my small knowledge of all of this. Skeptics need to realize that we are not going to win the climate debate by glad-handing each others comments, and failing to understand what the warmists are really attempting to say. If we are to refute warmist theories, we need to try and understand what underpins those theories, and show the flaws in them. That is exactly what people like Steve McIntyre and Dr. Roy Spence are so effective at doing
Phillip Bratby (02:29:58) :
John Finn, I disagree. If the global average temperature is nonsense, then so too is the derivative.
Your lake analogy is OK for the lake, because the lake has a single level. But the earth does not have a single temperature.
But each individual station/location has a single temperature.
No-one is interested in the average temperature – so why does it bother you? We are interested in whether the earth has actually warmed (or cooled). From the numerous ‘samples’ which have been measured over the past century or so (~30 years in the case of satellites) we can determine with a reasonable level of confidence the amount of warming (or cooling).
Firing on all guns:
“But those who interpret satellite data in this way are being sloppy. For instance, they never bother to investigate exactly WHY the warming occurred in the first place. […] Note that the major uncertainty here is what caused the warming in the first place. […] As a result of this inherent uncertainty regarding causation, climate modelers are free to tune their models to produce just about any amount of global warming they want to. […] They can simply assert that there are no natural causes of climate change, and as a result they will conclude that our climate system is precariously balanced on a knife edge.”
‘Vincent (05:49:53) :
Rhys Jagger,
Common sense is indeed, less common than we would think. There are a number of cognitive biases which cause people to make consistent errors of judgement. Eg, there is the “recency bias” which leads people to place more weight to recent events, statistics etc. which leads to interesting patterns in stock prices. More relevantly there is the “Confirmation” bias which leads to the tendency to search for or interpret information in a way that confirms one’s preconceptions.
I disagree with your MBA example though. You are assuming that all MBA’s are equal, so that it becomes irrational for people to pay more for the same product. But this is not the case. A Harvard MBA is clearly more valuable than one from Smallsville, and people are acting rationally in paying more for this qualification.’
I agree absolutely with you about your alma mater, if that is what it is!
The example was actually a damn good, but not absolutely elite school. I won’t name it for clear reasons, but I’m quoting from real life truth, namely the recruitment figures for a 4 year period for the same MBA programme. And the story was told me by one of the faculty of that school…….