Warming in Last 50 Years Predicted by Natural Climate Cycles
by Roy W. Spencer, Ph. D.
One of the main conclusions of the 2007 IPCC report was that the warming over the last 50 years was most likely due to anthropogenic pollution, especially increasing atmospheric CO2 from fossil fuel burning.
But a minority of climate researchers have maintained that some — or even most — of that warming could have been due to natural causes. For instance, the Pacific Decadal Oscillation (PDO) and Atlantic Multi-decadal Oscillation (AMO) are natural modes of climate variability which have similar time scales to warming and cooling periods during the 20th Century. Also, El Nino — which is known to cause global-average warmth — has been more frequent in the last 30 years or so; the Southern Oscillation Index (SOI) is a measure of El Nino and La Nina activity.
A simple way to examine the possibility that these climate cycles might be involved in the warming over the last 50 years in to do a statistical comparison of the yearly temperature variations versus the PDO, AMO, and SOI yearly values. But of course, correlation does not prove causation.
So, what if we use the statistics BEFORE the last 50 years to come up with a model of temperature variability, and then see if that statistical model can “predict” the strong warming over the most recent 50 year period? That would be much more convincing because, if the relationship between temperature and these 3 climate indicies for the first half of the 20th Century just happened to be accidental, we sure wouldn’t expect it to accidentally predict the strong warming which has occurred in the second half of the 20th Century, would we?
Temperature, or Temperature Change Rate?
This kind of statistical comparison is usually performed with temperature. But there is greater physical justification for using the temperature change rate, instead of temperature. This is because if natural climate cycles are correlated to the time rate of change of temperature, that means they represent heating or cooling influences, such as changes in global cloud cover (albedo).
Such a relationship, shown in the plot below, would provide a causal link of these natural cycles as forcing mechanisms for temperature change, since the peak forcing then precedes the peak temperature.
Predicting Northern Hemispheric Warming Since 1960
Since most of the recent warming has occurred over the Northern Hemisphere, I chose to use the CRUTem3 yearly record of Northern Hemispheric temperature variations for the period 1900 through 2009. From this record I computed the yearly change rates in temperature. I then linearly regressed these 1-year temperature change rates against the yearly average values of the PDO, AMO, and SOI.
I used the period from 1900 through 1960 for “training” to derive this statistical relationship, then applied it to the period 1961 through 2009 to see how well it predicted the yearly temperature change rates for that 50 year period. Then, to get the model-predicted temperatures, I simply added up the temperature change rates over time.
The result of this exercise in shown in the following plot.
What is rather amazing is that the rate of observed warming of the Northern Hemisphere since the 1970’s matches that which the PDO, AMO, and SOI together predict, based upon those natural cycles’ PREVIOUS relationships to the temperature change rate (prior to 1960).
Again I want to emphasize that my use of the temperature change rate, rather than temperature, as the predicted variable is based upon the expectation that these natural modes of climate variability represent forcing mechanisms — I believe through changes in cloud cover — which then cause a lagged temperature response.
This is powerful evidence that most of the warming that the IPCC has attributed to human activities over the last 50 years could simply be due to natural, internal variability in the climate system. If true, this would also mean that (1) the climate system is much less sensitive to the CO2 content of the atmosphere than the IPCC claims, and (2) future warming from greenhouse gas emissions will be small.
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Only fools or ideologists prefer, instead of a barbecue, kool-aid drinking, aaachhh!
Jim says:
June 8, 2010 at 10:20 am
Don’t be obtuse. Obviously I didn’t mean “why” as in “why is the sky blue, Daddy?” I meant “why” as in “how?” Where did the extra energy come from? What do the oscillations actually due to raise temperatures? What is the mechanism? Science does not work by saying A correlates to B, therefore A causes B, and we can’t know anything more. Why is always addressed by science. That’s the whole point of science.
Why do apples fall from trees? Gravity. Why do the stars move in the sky? The revolution of the Earth. Why is the Earth warming? Because of magical oscillations which are too complex and and arcane for the uninitiated to comprehend (queue dark, forbidding organ music here).
1DandyTroll says:
June 8, 2010 at 11:20 am
@Steve Garcia
‘The PDO, AMO and SOI are phenomena in themselves, driven essentially by the sun.’
Of course phenomenon, but I’d disagree driven essentially by the sun. I have come to understand that the oceans are driven by earth revolving around its own center in a yearly wobbly manner, the currents are created by the flat plateaus sticking up above em and endless mountain ridges below.
A small fraction of the solar radiation absorbed by the surface remains in the atmosphere as kinetic energy. Some 0.42 W/m^2 which are incorporated to the dynamics of the air and ocean currents.
Mark,
All models are wrong. Some models are useful. http://en.wikiquote.org/wiki/George_E._P._Box
***********
Sphaerica says:
June 8, 2010 at 1:03 pm
Jim says:
June 8, 2010 at 10:20 am
Can anyone explain why space is warped by gravity? Einstein’s equations only describe the shape of space in a gravitatinal field, not why it does it. It explains how the G.F. modifies time, but not why. Why is almost never addressed in science.
Don’t be obtuse. Obviously I didn’t mean “why” as in “why is the sky blue, Daddy?” I meant “why” as in “how?” Where did the extra energy come from? What do the oscillations actually due to raise temperatures? What is the mechanism? Science does not work by saying A correlates to B, therefore A causes B, and we can’t know anything more. Why is always addressed by science. That’s the whole point of science.
Why do apples fall from trees? Gravity. Why do the stars move in the sky? The revolution of the Earth. Why is the Earth warming? Because of magical oscillations which are too complex and and arcane for the uninitiated to comprehend (queue dark, forbidding organ music here).
**********************
I thought stars moved due to expansion of the Universe. Silly me.
Seriously though, Dr. Spencer may have revealed a couple of gears in the machine here. OK, it isn’t the whole enchilada, but as they say: A fool can ask a thousand questions in the time it takes the wise man to answer only one.
tonyb says: June 8, 2010 at 10:58 am
Vuk It looks interesting. I will email you separately
Just added one important graph.
http://www.vukcevic.talktalk.net/GWDa.htm
Sphaerica says:
June 8, 2010 at 12:52 pm
“His inputs are the PDO, AMO and SOI indexes, which can only be determined after they happen, and are themselves readings of sea surface temperatures.”
The important thing, though, is that their phasing is consistent, from the learning period to the modern period, with a natural reinforcement of a warming trend in the latter half of the 20th century. In the learning period, he gets the response from each cycle. In the modern period, he shows that the responses interfere constructively to produce a seeming warm trend.
All of these cycles are natural – they existed before the industrial age, and will exist into the future. When they are out of phase, they interfere destructively to create a cooling trend. When in phase, they interfere constructively to create a warming trend. And, they do so irrespective of any anthropogenic forcing. Capiche?
Jim says:
June 8, 2010 at 2:01 pm
I guess that’s my main point. I don’t think he’s added anything to our knowledge with this. It doesn’t help us to understand what’s happening, and really it doesn’t help us to understand anything. To me, this model is like saying “the big sun god is angry with us.” No one can prove it wrong, but there’s no next step.
There’s no place to go with this knowledge. It says “there are these mystical oscillations, which science isn’t even sure really represent tangible phenomena, and these mysterious oscillations are in turn responsible for the mysterious warming, except that we’re not admitting that there’s any warming, mind you.”
At the same time, the model has no predictive power, because its inputs are temperature measurements themselves. You can’t know the inputs you need until you know the end result… so if it doesn’t expand our knowledge or help us to understand the “how,” and it also doesn’t help to predict future climate change, then what is the value (except to convince simple people that this explains everything, and so they don’t have to think about it anymore)?
RHS:
At June 8, 2010 at 7:34 am you say:
“Besides, the earth needs us like a dog needs a flea.”
I agree, but the Earth needs me and most other people.
Richard
Gail Combs says:
June 8, 2010 at 12:33 pm
Translation: it’s inappropriate to have an opinion different from your own on the most important issue of our time.
Try arguing with facts instead of emotions.
Here you are being unnecessarily and foolishly alarmist. No one, anywhere, is talking about devastating economies, and no matter how dire the circumstances, the peoples and governments of the world would never have the self control to force themselves to pursue such a course, even if it were necessary. All we are talking about is starting now, investing 1% to 3% of GDP, in pursuing renewable energy sources and improving our infrastructure.
The only people who will suffer from this are those that stand to make lots and lots of money selling fossil fuels.
Evidence of your ignorance, and lack of critical thinking. If you’d read and understood enough, you’d understand that quote, and the context in which it belongs. Repeating it without understanding it is evidence of your position, and your lack of knowledge, nothing more.
Hint: He was talking about the fact that there are not enough, proper data collection mechanisms to account for all of the possible energy sinks on the planet. The problem was not that the globe wasn’t warming as expected, but rather that we know that it is, but cannot tally every nook and cranny to be sure that we understand exactly where and how and by how much.
Now you’re just having fun. “Not being used as ‘fact'”. That’s an interesting turn of phrase, a fun way to defend your original comments. “World’s most devastating hoax?” Spare me. As evidenced by what? How have you, or anyone, personally suffered in any way from the theory of AGW? And don’t say “they want to come and take all my things.” That’s nonsense.
You are one of the true “alarmists.” “Run, everyone, run, the global warming hoaxers are coming, and they’ll take your car and your job and your children. Run!”
So your position is basically:
1) The theory of AGW will destroy the world’s economies
2) Models are used in the theory of AGW
3) Models are evil, evil things… unless used by Dr. Spencer to disprove AGW, in which case it’s about time someone used models “properly.”
Bart says:
June 8, 2010 at 2:18 pm
Their phasing is not consistent.
You are assuming that he used some oscillating variable. I don’t believe he has, and he never said that he did. He said he used the indexes themselves, and they are certainly not regular, predictable oscillations. They are oscillations, but not regular, or predictable, so Dr. Spencer must have used the actual index values… or else his model would swing wildly away as his “regular” oscillations would vary from what really happens.
PDO
AMO
SOI
Another assumption. These values weren’t measured until the industrial age, so there is no way to prove your statement.
I’ll say it again. All he’s done is to take three major collections of temperature data, and to correlate them to global temperatures. It’s like expecting to find apples on the ground in an apple orchard. What’s the point?
Heh, oh, global one. No, the travesty is that Kevin Trenberth can’t face reality and understand his ‘heat in the pipeline’ has piped itself back into space, as he inadvertently let slip in his famous NPR interview two years ago.
Listen up, Bud; show me the effect of CO2 in the real world. We know it has radiative properties in the laboratory, but how do they play out in the oceans and the atmospheres? You can’t show me, and that you flap your lips like you do is a travesty.
==============
Sphaerica:
At June 8, 2010 at 9:54 am you ask Dr. Spencer:
“How does a planet with a relatively stable climate suddenly, dramatically warm?”
Before anybody can answer that question you nead to specify the planet to which you refer because it is certainly not the Earth.
Richard
Sphaerica:
At June 8, 2010 at 10:21 am you assert:
“You either believe it is appropriate to use models in science, or you believe it is inappropriate. So don’t dodge the question. Which is it?”
Rubbish!
It is appropriate and proper to use models in science. Indeed, science could not be conducted if it were unable to use models.
But it is inappropriate and improper to misuse models in science.
It is a misuse of a model to accept its output as being valid when the performance of the model has not been validated. Hence, it is misuse of a model to accept that its ‘projections’ of anything for several decades ahead are valid when the model has not existed for decades: this is a misuse of the model because the model cannot have any demonstrated forecasting skill for decadal periods and, therefore, is not a valid tool for the purpose.
Dr Spender’s has constructed a model and has used it appropriately.
Climate ‘projections’ of GCMs for the next 50 or 100 years are inappropriate and improper misuse of models. However, these ‘projections’ are not an example of the “use models in science”: they are an example of pseudoscience.
Richard
sphaerica says:
June 8, 2010 at 3:05 pm
I am not speaking of the phases of the oscillations – I am speaking of the phasing of their responses. A system generally exhibits a phase and a gain response. The gain response tells how an input will be scaled by the system to the output. The phase response determines when the output due to the input will manifest itself. And, that determines whether the total output will exhibit constructive or destructive interference.
What Spencer has shown is that the responses to PDO, AMO, SOI are repeatable, and that when you sum them together in the latter part of the 20th century, their phasing is such that they interfere constructively to create a temperature rise which is strikingly close to what we have, in fact, observed.
Richard S Courtney says:
June 8, 2010 at 3:18 pm
Sphaerica:
At June 8, 2010 at 10:21 am you assert:
“You either believe it is appropriate to use models in science, or you believe it is inappropriate. So don’t dodge the question. Which is it?”
If I may – models are used inappropriately when it is stated, as it is by AGW advocates, that there is no other type of model which will reproduce observed results. If you can show an independent model which does, then you have falsified that conclusion.
kim says:
June 8, 2010 at 3:09 pm
Uncivilized and unnecessarily vitriolic response, however…
The warming is quite undeniable, as evidenced by multiple temperature records (not just the ones WUWT likes to harp on… go visit Dr. Spencer’s site and tell me what you see) and Arctic ice, which is not behaving as Mr. Goddard would like you to believe… except when it melts you’ll switch your focus to some other variable, whatever you can find to pretend that nothing is happening.
Richard S Courtney says:
June 8, 2010 at 3:18 pm
Look around with open eyes of a true skeptic, instead of the closed tightly shut eyes of a WUWT self-labeled skeptic.
Translation: It’s inappropriate to use a model when you, R.S.C., personally disagree with the position or the outcome.
Except that the models have been validated (your refusals and huffing and puffing not withstanding).
Dr. Spencer’s model, on the other hand, says “look, if I put temperatures into a calculation, I get temperatures.”
It’s like predicting that a toaster will make toast. There’s no point to it.
Sphaerica:
Your trolling is tiresome so I shall address here one more of your blatant propogandist errors then ignore all your other comments. I hope this contribution will demonstrate to others that your contributions are inane and are intended to deflect attention from Dr Spencer’s excellent analysis.
At June 8, 2010 at 12:33 pm you assert:
“No one, anywhere, is talking about devastating economies, and no matter how dire the circumstances, the peoples and governments of the world would never have the self control to force themselves to pursue such a course, even if it were necessary. All we are talking about is starting now, investing 1% to 3% of GDP, in pursuing renewable energy sources and improving our infrastructure.”
Your assertions are untrue on every count.
Firstly, the IPCC, Greenpeace, WWF et al. are talking about reducing greenhouse gas (notably CO2) emissions. That is the purpose of the failed Kyoto Protocol, the aborted Copenhagen accord, and the putative Cancun Agreement. That purpose is not achievable by “investing 1% to 3% of GDP, in pursuing renewable energy sources and improving our infrastructure”, and the IPCC, Greenpeace, WWF et al. do not claim it is.
The reduction to CO2 emissions can only be achieved by reducing the use of fossil fuels.
But the use of fossil fuels has done more to benefit human kind than anything else since the invention of agriculture.
Most people would not exist if it were not for the use of fossil fuels because all human activity is enabled by energy supply and limited by material science.
Energy supply enables the growing of crops, the making of tools and their use to mine for minerals, and to build, and to provide goods, and to provide services.
Material Science limits what can be done with the energy. A steel plough share is better than a wooden one. Ability to etch silica permits the making of acceptably reliable computers. And so on.
People die without energy and the ability to use it. They die because they lack food, or housing, or clothing to protect from the elements, or heating to survive cold, or cooling to survive heat, or medical provisions, or transport to move goods and services from where they are produced to where they are needed.
And people who lack energy are poor so they die from pollution, too.
For example, traffic pollution has been dramatically reduced by adoption of fossil fuels. On average each day in 1855 more than 50 tons of horse excrement was removed from only one street, Oxford Street in London. The mess, smell, insects and disease were awful everywhere. By 1900 every ceiling of every room in Britain had sticky paper hanging from it to catch the flies. Old buildings still have scrapers by their doors to remove some of the pollution from shoes before entering
Affluence reduces pollution. Rich people can afford sewers, toilets, clean drinking water and clean air. Poor people have more important things they must spend all they have to get. So, people with wealth can afford to reduce pollution but others cannot. Pollution in North America and Europe was greater in 1900 than in 2000 despite much larger populations in 2000. And the pollution now experienced every day by billions who do not have the wealth of Americans and Europeans includes cooking in a mud hut using wood and dung as fuel when they cannot afford a chimney.
The use of fossil fuels has provided that affluence for the developed world. The developing world needs the affluence provided by the development which is only possible at present by using fossil fuels.
We gained our wealth and our population by means of that use.
The energy supply increased immensely when the greater energy intensity in fossil fuels became available by use of the steam engine. Animal power, wind power and solar power were abandoned because the laws of physics do not allow them to provide as much energy as can be easily obtained from using fossil fuels. (If wind power were sensible then oil tankers would be sailing ships).
The greater energy supply enabled more people to live and the human population exploded. Our population has now reached about 6.6 billion and it is still rising. All estimates are that the human population will peak at about 9 billion people near the middle of this century before it declines.
That additional more than 2 billion people in the next few decades needs additional energy supply to survive. The only methods to provide that additional energy supply at present are nuclear power and fossil fuels. And the use of nuclear power is limited because some activities are difficult to achieve by getting energy from the end of a wire.
If you doubt this then ask a farmer what his production would be if he had to replace his tractor with a horse or a Sinclair C5.
So, holding the use of fossil fuels at its present level would kill at least 2 billion people, mostly children. And reducing the use of fossil fuels would kill more millions, possibly billions.
That is not an opinion. It is not a prediction. It is not a projection. It is a certain and undeniable fact. Holding the use of fossil fuels at their present levels would kill billions of people, mostly children. Reducing the use of fossil fuels would kill more millions or billions.
Improving energy efficiency will not solve that because it has been known since the nineteenth century that improved energy efficiency increases energy use: as many subsequent studies have confirmed.
And this reduction to fossil fuel usage is a policy intended to stop climate change. But climate has always changed everywhere and always will: this has been known since the Bronze Age when it was pointed out to Pharaoh by Joseph (the one with the Technicolour Dreamcoat).
Joseph told Pharaoh to prepare for the bad times when in the good times, and all sensible governments have adopted that policy throughout the thousands of years since then.
That tried and tested policy is sensible because people merely complain at taxes in the good times, but they will revolt if they are short of food in the bad times.
So, you and your ilk want to replace want to move from the tried and tested climate policy that has stood the test of time since the Bronze Age, and you want to replace that with quasi-religious political madness which – if not stopped – will pale into insignificance the combined activities of Ghengis Khan, Adolf Hitler and Pol Pot.
Go away!
Richard
Sphaerica writes, in part,
“Also, kindly explain the mechanism (other than hand waving, magic, and climate gremlins) that is actually causing the warming. You’ve described it. You’ve quantified it. You’ve “predicted” it based on a correlation to three temperature based indexes. But explain it. How does a planet with a relatively stable climate suddenly, dramatically warm?”
To which Wren offers an answer,
“UHI effect ?”
But published research has looked hard and found little support for UHI as an explanation for the warming trends observed even in the surface-station parts of the NASA, NCDC or HadCRU series. To say nothing of the warming trends also noticed in, for example:
* ocean heat content
* wasting glaciers
* Greenland and West Antarctic ice sheet mass loss
* sea level rise due to all of the above
* sea surface temperatures
* borehole temperatures
* troposphere warming (with stratosphere cooling)
* Arctic sea ice reductions in volume and extent
* permafrost thawing
* ecosystem shifts involving plants, animals and insects
There’s more, but that’s already a lot of warming to explain.
Bart says:
June 8, 2010 at 3:31 pm
No, what Spencer has shown is that if you watch and see that 2 + 2 = 4, then you can create a model where 2 is the first input, and 2 is the second output, and look, amazing, 4 is the result.
As a side note, generally engineers or retired ex-engineers should not try to to apply their training to every single problem they see. “When all you have is a hammer, every problem looks like a nail.”
First, if this is Cycles … Why does it mimic the sudden rise recently ?
Previously, Spencer ascribed the “Up & Down” to the Cycles, with the last 30 years’ increase MOSTLY the cyclic Upturn. I understand that. Why the change ? An “unknown” factor (could be the Sun, in addition to Man) cannot have ANYTHING to do with it ?
If PDOs are hotter than 100 years ago — you need a reason.
Could Man (possibly through fishing Patterns) affect the PDO ?
Second: Your Arctic Temps (Dr. Roy S. co-monitors the derivation of uah Satellite temps: that he apologizes for them being high shows his Honesty, ie, he does not find some excuse to keep them low, unlike some other indexes)http://vortex.nsstc.uah.edu/data/msu/t2lt/uahncdc.lt
… are still running more than double ANY other year’s Arctic Ocean anomaly (anomaly is the temperature Above average)
Summarized: December through May … +3.20, 1.60, 2.92, 2.53, 2.68, 2.63 degrees C).
So I doubt it is time to FORGET that Man can Bolix things up, especially when there is Tax Money to be gained from causing a Panic – – thus it seems the last 34 years’ warming in the Arctic has been 74% from CAP & TRADE (1.09 of 1.48oC) , which laws “forgive” Soot from Diesels, force Industry on China — which has only coal = More BLACK SOOT on the formerly white Arctic — and the reductions in SO2.
I know this view is unpopular — either you are For Industry & claim Man cannot Change the Weather, or You are for the Green Agenda which Claims Industry is killing us.
I say it’s the Phony Greens that are killing us .
Well, the PPGs add 1.1 degrees to the Global +.4 … and, the 1 degree from the strong El Nino this year (unusual as normally when the Ice gets this thin from the Cycle as in 1948-54 – – it is after 30 years of melting during the positive side of the Cycle — which this should be, and, indeed we just had 2 La Nina … 1 of them VERY strong. I heard this was presdicted to be weak, but was pumped up by underesea volcanic Activity — giving us a 1-in-10,000+ year opportunity to melt off the Ice all at once & see if the Ocean Currents stop = 300 mph winds = 6 Billion Dead (since no one is Doing Anything about it) — providing someone gives us an extra degree or so … OOPs !
Un-thank you, Green Power !
PS: for Sea Ice Volume history from 1948 to 2004 clearly showing the 60-year Cycle, see http://psc.apl.washington.edu/zhang/IDAO/retro.html#NAO
[ignore the mid-1960’s Ice peak — it is from 3 volcanos]
sphaerica: So you agree that even though Dr. Spencer’s model is limited, it is nevertheless correct. So why the hysterics? You also said somewhere in your generous writings here that skeptics, the ones on WUWT, don’t acknowledge warming. That isn’t the case with most skeptics that post here. No, the skeptics here by and large believe CO2 does raise the lower atmospheric temperature. The skeptics here do doubt the other mechanisms posited by the warmist scientists, however. And they in general doubt the warming will be catastrophic.
On the topic of warmist scientists, one has to wonder why they define “climate” as a stretch of weather of 30 years when some of the ocean cycles take that long or longer and can run out of phase with each other. Shoot, you’d have to take a 100, 200, or an even longer span of years just to get a decent trend. Yet, the warmists claim not only that their models are correct, but the temperature record proves it. What’s up with that sphaerica?
The warmist scientist do so many questionable things, it seems a waste to turn your guns towards Dr. Spencer for such a simple but useful model. Why don’t you ask hard questions of the warmists? There’s a lot of “there” there.
Railing against Dr. Spencer won’t make warmist’s climate model’s right.
In the modern cycle we’ve been cooling since about ’98 and if you clean up the data you can push that. The warming through the 80’s is a minor dip in a long drift down from about the time of Christ.
Relative to the Holocene and looking at anecdotal data including the behaviour of Antarctica over the modern period we have been drifting into another glaciation for about 2000 years of this 500k year ice age (million years if you include period with moderated glaciations prior to Milankovitch cycle).
All we need is a Heinrich Event to really show us where we are in the calender and time stepping that to now … I give us a couple of millenia. A blip in geological time and a moment even in the 140k experience of human beings. That’s enough time to acknowledge our senses and wake up to reality.
Dr. Spencer,
Here’s what I did. Using monthly data from 1900 to April 2009 on Hadcrut global temp (not N hemisphere, which data I do not have handy):
1. HadCrut3 temp regressed with PDO, SOI and AMO http://i49.tinypic.com/2vcxpx4.gif
Rsquare is 27%. The Prob>|t| values |t| are <0.05, so all are statistically significant.
The Actual by Predicted plot falls on the red line, unlike in 1. and the Residual by Row plot falls on the horizontal line, unlike 1., indicating that adding CO2 makes a better "prediction" of Hadcrut temperature.
The Sorted Parameter Estimates pink bars show that CO2 is the most significant factor, followed by AMO, and the Leverage Plots give a similar result.
So:
A: What's "wrong" with MY analysis?
B: Why doesn't it show that CO2 is a stronger predictor of global temp than SOI, AMO and PDO?
C: What happens to your model when you add in CO2?
D: Tsfc means "surface temp"?
E: What tool did you use to get that "Correlation vs Lag" plot? Interesting.