Forecasting the Earth’s Temperature
by David Whitehouse via Benny Peiser’s CCnet
The recent spate of scientific papers that are attempting to predict what the earth’s temperature might be in the coming decades, and also explain the current global temperature standstill, are very interesting because of the methods used to analyse temperature variations, and because they illustrate the limitations of our knowledge.
Recall that only one or two annual data points ago many scientists, as well as the most vocal ‘campaigners,’ dismissed the very idea that the world’s average annual temperature had not changed in the past decade. Today it is an observational fact that can no longer be ignored. We should also not forget that nobody anticipated it. Now, post facto, scientists are looking for an explanation, and in doing so we are seeing AGW in a new light.
The main conclusion, and perhaps it’s no surprise, to be drawn about what will happen to global temperatures is that nobody knows.
The other conclusion to be drawn is that without exception the papers assume a constantly increasing AGW in line with the increase of CO2. This means that any forecast will ultimately lead to rising temperatures as AGW is forever upward and natural variations have their limits. But there is another way of looking at the data. Instead of assuming an increasing AGW why not look for evidence of it in the actual data. In other words let the data have primacy over the theory.
Lean and Ride try to isolate and analyse the various factors that affect decadal changes in the temperature record; El Nino, volcanic aerosols, solar irradiance and AGW. Their formula that links these factors together into a time series is quite simple (indeed there is nothing complicated about any of the papers looking at future temperature trends) though in the actual research paper there is not enough information to follow through their calculations completely.
El Nino typically produces 0.2 deg C warming, volcanic aerosols 0.3 deg C cooling on short timescales, solar irradiance 0.1 deg C (I will come back to this figure in a subsequent post) and the IPCC estimate of AGW is 0.1 deg C per decade.
It should also be noted that natural forces are able to produce a 0.5 deg C increase, although over a longer period. The 0.5 deg C warming observed between say 1850 and 1940 is not due to AGW.
The temperature increase since 1980 is in fact smaller than the rise seen between 1850 – 1940, approx 0.4 deg C. This took place in less than two decades and was followed by the current standstill. A fact often overlooked is that this recent temperature increase was much greater than that due to the postulated AGW effect (0.1 deg C per decade). It must have included natural increases of a greater magnitude.
This is curious. If the recent temperature standstill, 2002-2008, is due to natural factors counteracting AGW, and AGW was only a minor component of the 1980 -1998 temperature rise, then one could logically take the viewpoint that the increase could be due to a conspiracy of natural factors forcing the temperature up rather than keeping the temperature down post 2002. One cannot have one rule for the period 2002 – 2008 and another for 1980 -1998!
Lean and Rind estimate that 73% of the temperature variability observed in recent decades is natural. However, looking at the observed range of natural variants, and their uncertainties, one could make a case that the AGW component, which has only possibly shown itself between 1980 – 98, is not a required part of the dataset. Indeed, if one did not have in the back of one’s mind the rising CO2 concentration and the physics of the greenhouse effect, one could make out a good case for reproducing the post 1980 temperature dataset with no AGW!
Natural variations dominate any supposed AGW component over timescales of 3 – 4 decades. If that is so then how should be regard 18 years of warming and decades of standstills or cooling in an AGW context? At what point do we question the hypothesis of CO2 induced warming?
Lean and Rind (2009) look at the various factors known to cause variability in the earths temperature over decadal timescales. They come to the conclusion that between 2009-14 global temperatures will rise quickly by 0.15 deg C – faster than the 0.1 deg C per decade deduced as AGW by the IPCC. Then, in the period 2014-19, there will be only a 0.03 deg C increase. They believe this will be chiefly because of the effect of solar irradiance changes over the solar cycle. Lean and Rind see the 2014-19 period as being similar to the 2002-8 temperature standstill which they say has been caused by a decline in solar irradiance counteracting AGW.
This should case some of the more strident commentators to reflect. Many papers have been published dismissing the sun as a significant factor in AGW. The gist of them is that solar effects dominated up to 1950, but recently it has been swamped by AGW. Now however, we see that the previously dismissed tiny solar effect is able to hold AGW in check for well over a decade – in fact forcing a temperature standstill of duration comparable to the recent warming spell.
At least the predictions from the various papers are testable. Lean and Rind (2009) predict rapid warming. Looking at the other forecasts for near-future temperature changes we have Smith et al (2007) predicting warming, and Keenlyside et al (2008) predicting cooling.
At this point I am reminded that James Hansen ‘raised the alarm’ about global warming in 1988 when he had less than a decade of noisy global warming data on which to base his concern. The amount of warming he observed between 1980 and 1988 was far smaller than known natural variations and far larger than the IPCC would go on to say was due to AGW during that period. So whatever the eventual outcome of the AGW debate, logically Hansen had no scientific case.
There are considerable uncertainties in our understanding of natural factors that affect the earth’s temperature record. Given the IPCC’s estimate of the strength of the postulated AGW warming, it is clear that those uncertainties are larger than the AGW effect that may have been observed.
References:
Lean and Rind 2009, Geophys Res Lett 36, L15708
Smith et al Science 2007, 317, 796 – 799
Keenlyside et al 2008, Nature 453, 84 – 88
^^^
and BTW, if you do want an orifice for the mythical global thermometer you can pick the UK. That might be because the UK is like the ‘mouthpiece’ of the world, or OTOH it might not. I’ll leave the alternative as an exercise for the reader….
E. M. Smith,
“Well, I’d be willing to “take the bet” on the same terms as ctm were it not for two things:
1) The gubmint has been cracking down lately on ‘online gambling’ and I’m not willing to take THAT bet.
2) The logistics of dealing with the bet are not worth the potential gains.”
Both pretty poor excuses. The law does not make illegal to make bets online, just to run a business based on online betting. Hence your first excuse is worthless.
Given that you like the odds, your logistical argument is pretty lame as well. You would make £200 (or more than $300) just by typing a two word response, taking perhaps 10 seconds. I’ll pay by PayPal so all you need do is send me the account name, maybe another minute of work. That’s a rate of of $15,000/hour!
If you really have a problem with making such easy money, it really does look like you’re all talk and no trousers!
Richard Mackey (04:16:38) :
It is not very sensible to theorize about patterns of global warming or cooling without having regard to two major geophysical processes:
• the Earth’s variable rotation and its relationship with global temperature; and
• the Lunar Nodal Cycle and its relationship with the climate of the Arctic and the Pacific Decadal Oscillation.
In relation to the Earth’s rotation there is considerable evidence that decadal length variations in the rate of the Earth’s rotation result in periods of global cooling or warming.
Is this for real, or a Troll / Chain Yank / humour I don’t get?
I think the physics I learnt at age 12 proves that to be complete 00’s
To Tom P .
I’m not a gambling man – never have been and never will be.
Here’s one for you though, and all you other AGW guys out there. And also to Barrack Obama, Gordon Brown, Angela Merkel, et al.. Why don’t we have a voluntary tax that you pay if you believe AGW is real and you don’t pay if you believe that AGW is a total crock? Seems simple enough to me…
Alexej Buergin (05:52:07) :
I am sure that Einstein had many ideas, but you do not have to make a “square plural” of der Gedanke (sing.)/ die Gedanken (pl.). But you should square the sec in g. Otherwise it is a pleasure to see somebody calculating in “metric units”.
Hey Alexej,
Thanks for the corrections…..my missive was written late at night (for a lightweight like me) so I will blame the hour on my turning the Earth’s gravitational acceleration constant into a velocity…..
Regarding my misuse of the German plural and singular….I can make that mistake any time of the day (but hey I already told you I was no Einstein)…..
Score one for the (sometimes) corrective capabilities of blogs! Cheers!
Chris Schoneveld (01:03:04) :
“. . . I see it coming. Next claim will be that all the warming we have seen since the LIA is due to man.”
—————————–
Acutally, I do not think it is the “next claim.” It has already been claimed. See the chart SPM.2 from the AR4. According the IPCC, since 1750, radiative forcings from anthropogenic sources are over 13 times natural radiative forcings.
Despite the merits of Global Mean Temperature concept, I think it is clear from glacier retreat that the earth has warmed since 1750. Although AGW concerns often focus on the anthropogenic influence of the last 50 years, an “RW” poster on another blog has been very clear in his understanding that the warming since 1750 has been due to Greenhouse gases.
“”” E.M.Smith (16:06:26) :
George E. Smith (09:37:42) : But I suspect that GISStemp is a reasonable representation of the tiny network of thermometers (owl boxes) that make up the (near) surface network.
It isn’t.
It uses too many airports for UHI adjustment (treating them as rural). It uses places very unlike an urban area and very far away as proxies for it (they are not). It divides the world into 6 latitude bands (and hides the major movement of thermometers south in those wide bands). And much much more… “””
E.M. you are missing my point. If I go to my local supply house; say Van Waters & Rogers, and I purchase 12 calibrated Mercury in glass thermometers having a -20 deg C to + 200 deg C range that are accurate to 0.5 deg C when used according to the manufacturer’s specifications (maybe imersion depths and such like); I can now place these thermometers around my house in various places; one in the oven, one in the refrigerator, one in the freezer, one on top of the TV, etc
So each day I go and read each thermometer and note the reading; maybe I do it twice a day; and being a working stiff, I would read them all before I leave for the office, and 12 hours later when I am home again.
I can gather this data for 10 20 150 years or so, and statistically process all those numbers to compute an average daily temperature for that specific set of 12 thermometers; and I can plot lots of nice graphs, and do regressions, and trend lines and all such statistical trickery.
And what I am doing is a perfectly valid protocol for me to use for my set of 12 themometers; for whatever reason I am spending this time and effort.
Where I get into trouble is when I assert that the data and the computed results of whatever statistical mathematical prestidigitation I have done; in any way shape or form, represents a “global average” temperature for my house.
Same thing gor GISStemp; whatever Hansen does with the numbers received from his collection of thermometers; is perfectly reasonable for his aims on what he wants to get from that specific set of thermometers; That includes all the ones that are in Urban Heat islands; particularly that Climatologically Engineered one at the University of Arizona.
But just as my set of 12 thermometers is not properly sampling the total temperature map of my house; so too, Hansen’s set are not properly sampling the total global surface temperature map. It is perfectly valid to take a temperature sample inside a UHI, or any number of UHIs. What is not valid is to apply those UHI readings as representing the temperature in some tropical rain fores 1200 km away from the UHI. That is where the Nyquist Theorem comes into play, and dictates that you must sample the continuous function at a rate not less than twice the highest frequency contained in that (band limited) continuous function; and in this case we have a continuus function in space and time, and have to satisfy the criterion as to both variables.
Which is why I say that GISStemp graphs are probably good representations of GISStemp; which I define as simply whatever AlGorythm, Hansen applies (consitently) to his limited thermometer set. But it is when he extrapolates, and asserts that his graphs relate to this planet’s behavior; that Is when I yell foul; they are no more a valid representation of planet earth’s mean surface temperature, than are my 12 thermometers in my house representative of my house. And if my wife is baking a cake when I read the oven thermometer; I’m likely to get a strange reading; which I will process like any other as Hansen does; but I will find that I have not properly evaluated the frequency spectrum of my house temperature signals, and I have failed to comply with Nyquist’s Sampling Criterion.
George
Betting! Julian Simon would enjoy that if he were alive today. Paul Ehrlich lost.
I’m confused, I thought that CO2 followed temperature not the other way round?
I’m not either. But the bigger problem is that neither side can prove their case (actually AGW needs to prove their case, since natural variability is the default position)
Ah that old favorite “the cooling is masking the warming” handwave. Usually reserved for the Antarctic non-warming. The trouble is that when you change your story all your other hand-waves come back to haunt you. The team (Mann, Trenberth et al) made made great play about the solar variations not being able to explain temperature beyond 1980 (Lockwood+Frohlich used 1985). Implicitly thereby they admitted that it correlated very well for hundreds of years up to that 1980 cutoff as can be readily seen on the NASA site or Solanki’s site.
They really weren’t expecting this 12 year stall. So now that very weak and declining natural variability is apparently overcoming the very strong GHG effect and they all scuttle back to the 100 year trend for support. But some of us still remember the IPCC 1950 cutoff for AGW and we remember too the 1980 cutoff of the solar debunkers. If you want to change your story now get it in the next IPCC papers. Or better still be honest and admit you don’t have a clue.
The sensible ones are obviously backing down gradually in order to save face while the fanatics are still concocting new hockey-sticks and getting shriller – before it’s tooo laaaate.
Got to laugh at RW’s 10 year weather event. The “weather noise” handwave again! Only in climate science would you assume the declining end of a time series was noise. Here’s a scoop – It’s not noise it’s a signal.
Jeff Alberts,
“I’m not a gambling man…”
That might be why you’re missing the point. This bet will not prove anything but is rather predicated on my assessment that I have a greater understanding of what might be the drivers of temperature change. Of course Charles believes the same, so he is willing to enter the bet. Natural oscillations will indeed mask any longer term trend, hence the square-root dependence of the stake with integrated time. As time increases anything other than a flat trend will ensure one of us ends up winning until the other concedes.
For instance, if in 1900 Arrhenius, after he first published the theory that CO2 was warming the atmosphere, had made an identical bet with one of Charles’ ancestors, he would have lost in the first four years but ended up more than $25,000 by the time of his death.
Reply: I’m just doing it because it’s fun. In my worldview or “understanding”, it is simply a coin flip. I have no idea if I will win or lose. ~ charles the moderator
masonmart (22:42:02) : “Nick Stokes, what you are saying is that AGW is not based on physical observations but only on the weak AGW hypothesis/belief? I knew that this was true but to hear it from a Canutist is brilliant. Model based hysteria and pseudo science. The house of cards is falling.”
You are traducing the memory of an intelligent man.King Canute would certainly have been a sceptic. The story is that Canute’s obseqious courtiers believed that he was so powerful that he could even stop the tide coming in. To show these fools that he was not all-powerful, Canute ordered his throne to be put on the beach and sat on it as the tide came in and ordered the tide to stop. The tide came in anyway and soaked him. He proved his point.
We need a political leader of Canute’s intelligence today!
“Here’s a scoop – It’s not noise it’s a signal”
Got to laugh at JamesG’s hilariously unwarranted certainty. Talk about faith!
Jeff Alberts (14:19:02): I’ll go you one better. There is no “Global Mean Temperature”. It’s an artificial construct that is completely meaningless.
Yes. Please read chapter 1-1 in this excellent book we had in school:
http://books.google.co.uk/books?id=dcCpdY_Y2CEC&lpg=PR11&ots=7yJSXXYXIu&dq=treatise%20on%20irreversible%20and%20statistical%20thermodynamics%20wolfgang&lr=&pg=PA4#v=onepage&q=&f=false
Temperature is strictly speaking only defined at a point in equilibrium. On the other hand, I think it is perfectly clear that our earth was much colder during the last ice age. If we approach a new ice age due to low solar activity, we cannot sit on the fence and say there is no global mean temperature.
Possibly global temperature may be a more meaningful concept if we relate it to the global energy, however, there are so many subtle energy forms that the concept would be highly disturbing. Still, in order to calculate some sort of bulk average temperature, we should at least take into account the thermal mass of the air and the oceans, since there is no law for the conservation of temperature – it is the energy that is conserved.
“an “RW” poster on another blog has been very clear in his understanding that the warming since 1750 has been due to Greenhouse gases.”
You’ve probably misunderstood what this “RW” character has said. You, and other posters, seem to be under the impression that climate change over any period can be ascribed to one single variable. Let me assure you that this is never, ever the case. If you see anyone promoting a document entitled, for example, “Nature, not human activity, rules the climate”, you should tell them this.
Charles,
“I’m just doing it because it’s fun.”
You’re a sport!
I’m surprised that of all the contributors to this site who have in the past vehemently stated that the world is cooling not a single one has taken me up on my bet.
Instead of grumbling about unwarranted carbon taxes, this should be a perfect opportunity to make some money as a hedge. Why the loss of nerve?
Tom P
Few people are willing to jump off the cliff into the cold water because it’s fun. But it’s ok for the rest of us to do it.
An Inquirer
I think you’ll find quite a few people bet on red or black at the roulette wheel, just not those who are gambling averse.
“”” Invariant (13:23:19) :
Jeff Alberts (14:19:02): I’ll go you one better. There is no “Global Mean Temperature”. It’s an artificial construct that is completely meaningless.
Yes. Please read chapter 1-1 in this excellent book we had in school:
http://books.google.co.uk/books?id=dcCpdY_Y2CEC&lpg=PR11&ots=7yJSXXYXIu&dq=treatise%20on%20irreversible%20and%20statistical%20thermodynamics%20wolfgang&lr=&pg=PA4#v=onepage&q=&f=false
Temperature is strictly speaking only defined at a point in equilibrium. On the other hand, I think it is perfectly clear that our earth was much colder during the last ice age. If we approach a new ice age due to low solar activity, we cannot sit on the fence and say there is no global mean temperature. “””
Well your thesis is not correct, and moreover your cited reference does not even say that “”” Temperature is strictly speaking only defined at a point in equilibrium. “””
What it does say; is that things (and thermometers) that are in thermal equilibrium with each other will all register the same temperature.
But today temperature is defined in terms of the kinetic energy of particles, even a single atom has a temperature, and that temperature could be changing rapidly as that atom collides with other energetic atoms or molecules.
As for the “Global Temperature”; or shall we restrict it to say the “global surface temperature”; it most certainly has a value at any instant in time, and it certainly has an average value taken over any time frame such as a complete sun orbit for example.
The problem is we have no method of measuring the complete global surface temperature map to the required resolution to compute even the single instant of time global surface mean temperature; even satellites can’t do it, becasue no satellite has instantaneous 4pi coverage of the earth’s surface to even take a snapshot of the complete temperature map.
I don’t know what any of the orbital periods of surface sensing satellites is, but potentially they can scan enough of the surface to register several data points each day for any point on the surface; but they aren’t simultaneous, so that complicates the data reduction.
But the more important point is that the global mean surface temperature even if we could measure it, tells us nothing about the energy flows into and out of the earth’s surface; and that is what the big question is; are we gaining or losing net energy on this planet ? And in that sense “global mean temperature” is meaningless; besides being unmeasurable.
George
Tom P:
Seldom will I bet when the odds are 50/50 that I will lose. Economists believe that most people are risk adverse and will not bet on a 50/50 proposition (except for entertainment), and I certainly am one of them.
To me, It is a 50/50 chance that the GMT will be cooler or warmer next year and beyond. It fact, regardless of AGW, there may be a warming trend due to recovery from the LIA. I do not know when the recovery will be complete, and I do not see any sure science that explains what is driving the recovery or how long it will continue before the next set of variables induce a trend in the next direction.
I do have bet offers for which I have no takers:
1) Al Gore’s warning of ice-free Arctic by 2013.
2) $100,000 on ice-free Artic by 2030. (I would like to double my granddaughter’s inheritance.)
3) The status of the polar bears in 2050.
Excellent post, thank you.
An Inquirer,
If you think the world is warming you would indeed be misguided to take my bet.
But recovery from the LIA? Here’s the historical temperature time series combining the global temperature derived from glacier history and the instrumental record:
http://img9.imageshack.us/img9/1994/glaciervsinstrumental.png
It certainly doesn’t look like the slow recovery over many centuries that would be expected according to your hypothesis.
JamesG (10:12:14) : “The team (Mann, Trenberth et al) made made great play about the solar variations not being able to explain temperature beyond 1980 (Lockwood+Frohlich used 1985). Implicitly thereby they admitted that it correlated very well for hundreds of years up to that 1980 cutoff as can be readily seen on the NASA site or Solanki’s site.”
You can add a few more years to that. From the IPCC Report AR4 2.7.1.3 : “In particular, the cosmic ray time series
does not correspond to global total cloud cover after 1991 or
to global low-level cloud cover after 1994 (Kristjánsson and
Kristiansen, 2000; Sun and Bradley, 2002) without unproven
de-trending (Usoskin et al., 2004).“.
Incidentally, they then go on to describe ways in which it might or might not correspond over different periods, before dismissing it and cutting the amount allowed for solar variation. They then say “The level of scientific understanding is elevated to low relative to TAR for solar forcing due to direct irradiance change, while declared as very low for cosmic ray influences (Section 2.9, Table 2.11).“.
It beggars belief that the MSM and others treat their “findings” as gospel.
George E. Smith (14:09:26) Well your thesis is not correct, and moreover your cited reference does not even say that “”” Temperature is strictly speaking only defined at a point in equilibrium. “
Citing from the book:
“To find the temperature at a point in a system undergoing a change, let us suddenly isolate a small element of space surrounding the point and allow the matter to reach equilibrium; the temperature then measured in the usual manner defines the temperature at the point. [] For a macroscopic point of view, on the other hand, we shall require the element to be small.”
It is a long way to go from the kinetic energy of a molecule to the bulk temperature of a large body, but thermal simulations that are of vital importance in many critical engineering installations leaves little room for philosophical definitions of temperature. Nearly all equations in the book I cited are differential equations valid only for a single point in space at local thermodynamic equilibrium. In practice the kind of local thermodynamic equilibrium we talk about here is reached very quickly both in time and space, however, all equations we use in thermodynamics are strictly speaking only valid at local thermodynamic equilibrium. Outside local thermodynamic equilibrium temperature is not defined, at least not in the classical way that leads to useful and observable temperatures that can be used to simulate thermal installations. See this link:
http://en.wikipedia.org/wiki/Thermodynamic_equilibrium#Local_thermodynamic_equilibrium
“Global thermodynamic equilibrium (GTE) means that those intensive parameters are homogeneous throughout the whole system, while local thermodynamic equilibrium (LTE) means that those intensive parameters are varying in space and time, but are varying so slowly that for any point, one can assume thermodynamic equilibrium in some neighbourhood about that point.”
Here the main point is “varying in space and time, but are varying so slowly”. So in a sense most dynamical systems vary so slowly in space and time that we can assume local thermodynamic equilibrium. This is important, since it means we can use all the wonderful equations in the above mentioned book.
Global temperature on the other hand is a philosophical concept, but I argue that we should at least adjust for the fact that the thermal mass in the oceans is huge compared to the thermal mass in the air. In this way the global temperature will be a better measure of the state of our earth and whether we are approaching a new ice age or not.
And since no one knows the EU is turning up the heat to get climate regulations to go global:
http://www.ecnmag.com/news-EU-Global-Climate-Pact-091009.aspx?menuid=0
“……….and yet atmospheric CO2 concentrations started rising in about 1750. CO2 did not suddenly become a greenhouse gas at some point after 1940……’ RW (11:57:26).
But the temperature rise prior to 1940 cannot be attributed to anthropogenic emissions, i.e. the burning of fossil fuels.
http://photos.mongabay.com/09/0323co2emissions_global.jpg
1940-1980, the temperature was in stasis.
2000-2009, the temperature has been in stasis.
The entire temperature trend 1940-2009 occurred 1980-2000.
http://www.woodfortrees.org/plot/hadcrut3vgl/from:1940/to:2010/mean:13/plot/hadcrut3vgl/from:1940/to:1980/trend/plot/hadcrut3vgl/from:1980/to:2000/trend/plot/hadcrut3vgl/from:2000/to:2010/trend
“At what point do we question the hypothesis of CO2 induced warming?”
There are many who have always questioned the hypothesis. After all, the hypothesis was and is extremely weak as scientific theories go. It only described about 60 years of the billions of years of climate history, and not even that if you question the groundless assumption of aerosol cooling. Simply put, the theory is almost baseless and has always been that way.
I am just an operational meteorologist who has questioned the hypothesis since the early 1990s. I find it interesting that researchers are just now beginning to say the same things people like me have been saying for nearly 2 decades, and acting like it is a revelation. It would be funny if the whole thing didn’t cost so much.