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
Our web site has a couple of sections which are of relevance. At..
http://www.climatedata.info/Forcing/Forcing/volcanoes.html
.. we show that the only cooling mechanism in GCMs is the effect of volcanoes.
And at…
http://www.climatedata.info/Forcing/Forcing/0scillations.html
.. we illustrate the combined effect of El Nino and volcanoes on short term (few year) temperature variations.
If models (*) are mostly uncovered or even undressed it is because it’s hot, if models are not then it is going to be cold but anyway cool.
(*) fashion models not Hansen’s
And the Optimum Population Trust figures we can solve the whole problem thru contraception: http://www.telegraph.co.uk/earth/environment/climatechange/6161742/Contraception-cheapest-way-to-combat-climate-change.html .
As usual.
Well can we get some concensus here; are we talking about computed anomalies or actual temperatures. I for one don’t believe we can even measure the true earth (surface) mean temperature to anything like the accuracy implied by the published anomaly graphs.
GISStemp and other anomaly measures don’t have any real relationship to true global surface temperatures; the sampling density simply is orders of magnitude less than required for noise free recovery of the complete surface temperature map, and hence accurate computation of its average value; even its average value for s single instant; let alone averaged over a complete sun orbit. And even if we could measure it; that number we obtain is as useful as the average telephone number in the Manhattan phone directory; it tells us nothing about the global energy balance.
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 is one thing to apply some AlGorythm to an arbitrary set of data sensors, to compute some defined function of those numbers; but it is a completely different problem to connect that set to the actual planet we live on.
George
PS Yes I believe that it warms and cools; and no I don’t believe we have anything much to do with it.
1. Is there agreement that the ‘way we measure temperature’ is ‘consistent’, ‘reliable’ and ‘settled’?
2. If not is this argument pointless?
3. If so, when will people stop discussing it until point one IS settled?
4. Is that likely to be after Al Gore’s ‘cleantech boom-bust’ cycle has made him a billionaire and a bunch of silly investors bankrupt?
This is very similar to the forecast I have made for the next decade or so, I would though, on the basis of recent drops in global temperatures being far stronger than any AGW warming component, expect to to see even larger drops through this extended cold period, rather than reduced levels of warming. Murphy`s winter, here we come again!
http://climaterealists.com/forum/viewtopic.php?f=4&t=208
http://landscheidt.auditblogs.com/2008/06/03/the-sunspot-cycle-and-c24/
For my own assumptions, I like to use a probabilistic approach. The basic question asked is: is it more likely that temperatures are in a generally rising or generally falling trend?
Judging from past responses to things like PDO and ENSO, it seems reasonable that temperatures will generally decline for some period of time going forward, probably for something like 25-ish years beginning in 2006. So I expect temperature declines, in a general trend sense, until sometime around 2030.
Judging from the steady decline we have seen over the past three consecutive years in the continental US, there is empirical evidence that reinforces that conclusion. ( go here, in the Period pull-down, scroll all the way to the bottom, select “latest 12-month period”. In “First year to display”, select 1999, then click “submit” at the bottom of the form.)
There is a good chance we are in the same place in a naturally occurring cycle that we saw from 1950 to 1975 (plug those numbers into the above referenced form for first and last years to display to see the trend).
Now as for duration and slope of the cooling trend, that takes a crystal ball. But overall, I would say there is enough evidence to state with some degree of confidence that it is more probably that the next several years will be cooler than this year. Nothing tells me how MUCH cooler, just that it will generally be cooler. So if I were a farmer, I would plan on strains of crop that do well with a shorter growing season.
If you go back to that form and click “precipitation” rather than “temperature” you will see that over the same time there was a trend if increasing precipitation, in general, across the continental US during that same period. So cooler, wetter, conditions are probably in store generally but can vary widely locally. Locations that saw prolonged drought might see a return of those conditions. Locations that saw flooding and increases in snowfall might also see a return of those conditions though maybe not as great or maybe to a greater extent than that period.
Judging by the slope of the current trend, it appears that the current cooling trend might be greater than the 1950 to 1975 trend but there aren’t enough data yet to tell with any degree of real confidence.
If I were a farmer or a heating oil salesman or in the snow removal business or any business that is impacted by weather, I would look at my local trends between those years in the past and position myself generally to take greatest advantage to the extent possible of a likely repeat of those conditions.
As for making exact predictions from one year to the next, I will leave that up to the psychic down the street because even within that period of general down trend, it was not a monotonic decline, one year might still be warmer than the previous.
The interesting point is that these are presumably peer reviewed papers – and there seems to be a renewed questioning of the consensus view. Opening up the issues of how well the climate is understood is much more interesting than blindly questioning the precision of temperature measurement, which is just a distraction.
I think we can expect more work in this area – enough people are keen enough to have their name on a groundbreaking paper, and this could be their opportunity. There is not so much chance of a breakthrough in supporting the consensus.
The main problem with all models is that they have four independent variables (solar, GHGs, human and volcanic aerosols) and only one dependent: temperature (or two if you include precipitation).
That means that any combination of the four forcings with their own climate sensitivity will give you the right answer: the past temperature trend. Which is a necessary, but far from sufficient condition for a model to be of predicitve value.
All current models have similar sensitivities for the same change in forcing. But that is far from sure: solar has its largest effect in the stratosphere (UV/ozone/jet stream positiont/cloud-rain patterns) and in the light/energy penetration of the ocean’s surface in the tropics, while GHGs have their largest effect spread over the latitudes and the lower troposphere. This was seen in a test of the HadCM3 model by Stott e.a.:
http://climate.envsci.rutgers.edu/pdf/StottEtAl.pdf
The main conclusion (within the constraints of the model, like a fixed influence of human aerosols): solar variation may be underestimated by a factor 2 (at the cost of the influence of GHGs).
Further, the influence of human aerosols is quite unsure (even the sign can be discuted!), but that has a huge influence on the (possible) sensitivity (including feedbacks) of GHGs. See:
http://www.ferdinand-engelbeen.be/klimaat/oxford.html
“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.”
Imagine that!
Data over theory.
Sadly, in scientific discipline after scientific discipline, theory trumps data.
The imagnination and desires of men have a firm grip on Science.
No surprise there.
But when theory trumps data, one can not claim the state of Science is “clearly healthy!” with a straignt face and retain credibility.
But perhaps after this experience with the inscrutible Sun men will be humble and more open-minded and less attached to figments of imagnination flickering on the cave wall.
“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 publication is nothing more but another attempt to keep the CO2 AGW hoax alive by packing the lack of warming in a semi scientific smoke curtain.
“Solar irradiance counteracting AGW”, how smart a scientist do you have to be to come up with such a BS statement.
The answer to that question is easy.
These guys are collaborators serving a political agenda.
Think Copenhagen December 2009, nothing more nothing less.
You know what they say . . . never make predictions. Especially about the future.
By the way, UAH MSU files, August 2009 saw an anomaly-wise 0.18 °C cooler than July 2009.
This means that about one half of the abrupt warming between June and July was reversed between July and August.
I don’t know what the future will bring but if I am aloud to gamble, I say we will continue to cool.
Rhys Jaggar has it right. Until we can get past his point #1nothing else matters. How can we forecast the temperature when we can’t tell what the temperature is or has been?
This whole piece is a tiresome mixture of half-truths, untruths, misunderstandings and simple mistakes.
There is no “current global temperature standstill”. The trend in temperatures from x-present is not statistically different from the trend from x-1998, or x-2002, or x-2005, or whichever date you want to cherry pick. Yet again, you allow yourself to be fooled by weather. Will this ever stop?
There is no “IPCC estimate of AGW”. The quantification of the expected temperature rise is far more complicated than the single number you wrongly attribute. In fact, in this and the next few decades, the expected warming from the rise in CO2 would be about 0.2°C, not 0.1°C.
“The 0.5 deg C warming observed between say 1850 and 1940 is not due to AGW” – and yet atmospheric CO2 concentrations started rising in about 1750. CO2 did not suddenly become a greenhouse gas at some point after 1940.
The GISS temperature record starts in 1880. By 1988, therefore, there was 108 years of instrumental global temperature data, not “less than a decade of noisy global warming data”.
There is another effect to add, which is the gravitational energy imparted to the ocean due to moving mass inside the Earth. Currently modellers use the GRACE satelite data, I believe, to provide an estimate of ocean circulation. GOCE will provide a higher resolution and as I have read may bound the model uncertainties with regards to deep ocean currents and motion by an order of magnitude. Finer detail may reveal more information concerning the Earth’s oceans oscillation patterns and heat transfer. This could help explain the temperature variations observed on the surface. One of the questions I have is what happens if you don’t vary the sun’s output at all? Can long term (50 years +) temperature variations be described by the dynamics of processes on the Earth alone. Ice ages seem to match orbital effects for instance.
I’d just like to give UK contributers a heads up on the UK Foreign Secretary David Milliband’s on-line blog.
Among other things it’s covering his days leading up to the Copenhagen Climate Summit in December.
In one blog he describes:-
At Paris’ Sciences Po University yesterday I said that if Europe successfully led the way to global climate deal, the EU would come to be recognised as an “Environmental Union”.
Readers comments are welcome, but are as yet very thin indeed.
http://blogs.fco.gov.uk/roller/miliband/
“Lean and Ride(sic! You mean Rind) try to isolate and analyse the various factors that affect decadal changes in the temperature record; El Nino, volcanic aerosols, solar irradiance and AGW.”
“There are considerable uncertainties in our understanding of natural factors that affect the earth’s temperature record.”
I agree that, at first instance, we should look for an explanation without AGW, the more that it is still possible that CO2 is in lagged equilibrium with temperature.
L&R try to account for the recent temperature standstill only through the effect of the given factors on the short term. It is clear that the result is not satisfactory. But there are also changes in the long run, in particular in the oceans. Warming (and cooling) of the ocean occurs on interdecadal and even on centiannial period scales. Does anybody know what’s the temperature in the oceans on a depth of 1 or 2 km or what’s the temperature on the ocean-floor? Possibly these temperature will influence climate on a certain manner within twenty of more years, I don’t know.
It is quite simple to say that any global warming is caused by AGW. It is not simple at all to look for other factors which still have to be discoverd and which are working on the longer term.
It seems me that the authors in this new paper (2009) have an opinion that is opposite to that of 2008. Then they argued: “According to this analysis, solar forcing contributed negligible long-term warming in the past 25 years and 10% of the warming in the past 100 years.”
Now, they state:”But as a result of declining solar activity in the subsequent five years [from 2014 to 2019], average temperature in 2019 is only 0.03±0.01 C warmer than in 2014. This lack of overall warming is analogous to the period from 2002 to 2008 when decreasing solar irradiance also countered much of the anthropogenic warming.”
Have they been overtaken by events??
Murphy’s winter (excellent !) is a part of Murphy’s climate, and it has found a perfect target in the form of the assumptions of Global Warming.
Murphy was last seen heading up Mt. Shasta. 🙂
2 simple & serious problems with the decompositions that are leaned on so heavily:
1) untenable assumption of randomness that goes into their determination.
2) shared variance.
While it isn’t wrong for investigators to do what they can with what is available, statements must be appropriately qualified according to limitations & uncertainties — and to be blunt: we’re generally not seeing that, which suggests either:
a) fundamentally flawed reasoning (such as blind &/or unquestioning acceptance of untenable assumptions), – &/or –
b) deceit.
In summary: Arrogantly unqualified decompositions are more than suspect and will remain so until our understanding of natural climate variations increases by orders of magnitude. There is no way to weasel out of this.
The full paper is available on the NASA GISS website.
http://pubs.giss.nasa.gov/docs/2009/2009_Lean_Rind.pdf is the direct link to the pdf.
The abstract and the link to the pdf are on:
http://pubs.giss.nasa.gov/abstracts/2009/Lean_Rind.html
Excellent article! This is one of many interesting passages:
Those papers are flat wrong. I don’t really care how peer reviewed they are. I’m not judging their worth. Planet Earth is showing us they are wrong. And the planet, unlike people, doesn’t lie. What you see is what you get.
Anyone looking at what has happened over the past decade must admit that any warming due to AGW has been hugely overstated.
When temperatures were temporarily rising concurrently and coincidentally with the rise in CO2, a case could be made that CO2 was a major cause of the warming.
But for most of the past decade temperatures have been flat to falling, while CO2 continues to rise. CO2=AGW is a canard, propped up by endless financial grants, without which it would quickly fade from the public’s consciousness.
It is apparent that CO2 has such an insignificant effect on temperature that it can be completely disregarded for all practical purposes. In fact, the evidence proves that more CO2 is beneficial.
It is hard for people to change their minds, after being told for years that CO2 causes global warming. But given the failure of the climate to warm for most of the last decade as CO2 rises, the conjecture that CO2 causes global warming is unsustainable.
Only one CO2 molecule out of 34 is emitted by human activity. The rest are natural emissions. The AGW conjecture is built on sand. It is preposterous to believe, as the alarmists tell us, that a few percent change in a very minor trace gas will cause the climate to go into runaway global warming. In the geologic past CO2 has ramped up to thousands of ppmv, for hundreds of millions of years at a time. The result? The Earth was teeming with life.
Now that it is clear that CO2 has such an insignificant effect [or possibly no empirically measurable effect; we don’t know for certain], it is time to cut off the enormous flow of wasted taxpayer dollars being funneled into climate studies, and re-direct it to other scientific endeavors that will produce actual benefits.
Sometimes the TV-forecasters’ modify the small label aimed for showing the “current” temperature during the transmissions for their forecasts don’t fall short. For example, a local TV-forecaster predicted T max 35 °C yesterday. We could see how the T on the label of that channel went increasing until reaching 35 °C. However, the T max reported by the airport and our own thermometers was 27 °C in rural locations and 31 °C in urban heat islands. Do you see the trick? People will never see Biocab’s thermometers for checking out the temperature, but the small label on the screen of their TVs. 🙂
Carbon offsets were trading at $7 and have fallen to 25 cents. Must be a lot of hand wringing on this.
“How can we forecast the temperature when we can’t tell what the temperature is or has been?
Is anyone aware of any studies comparing hourly temperature profiles:
(a) seasonally (I found one for Athens), and
(b) sensor base (concrete pad vs grass)