2011-02-03 12:54:39A Challenge to the Climate Research Community from Roy Spencer
John Cook


Roy Spencer throws down the gauntlet:

Show me one peer-reviewed paper that has ruled out natural, internal climate cycles as the cause of most of the recent warming in the thermometer record.

My immediate thought - Barnett 2007 rules out natural variability as the driver of the observed pattern of ocean heat:


Can anyone build on this? I wonder if all the papers we cite for human fingerprints also can build on this body of evidence. This might be worth exploring and shaping into a blog post - a good opportunity to answer Spencer's challenge, write a rebuttal to the "it's internal variability" argument and further reinforce the evidence for an anthropogenic signal.

2011-02-03 17:42:32
Ari Jokimäki


Use Pierce et al. (2006) instead of (or in addition to) Barnett et al. (2001) - same research group:


Here are some attribution studies which might be relevant here:


Here are some papers on natural variability:


2011-02-03 21:27:05
Mark Richardson

John, he's not arguing that it's ocean heat.


His main argument* is that regional changes from 'natural cycles' can lead to a net radiation imbalance, primarily through clouds. This then leads to a buildup of heat in the oceans.

As I understand it, you can start to follow it by imagining the world split into 2 regions of ocean and clouds linked to temperature by clouds = temperature squared.

Let's say they originally start at 10 C (=100 clouds each for 200 total). Now warm one half by 2 C and cool the other half by 2 C so you keep a constant average temperature but clouds are now 208. If clouds have a net radiative effect, then you've just created a cooling simply from the noise in the system. So long as cloud radiative forcing isn't linear with temperature at each location then you can generate interal radiative forcing, which would cause heating and so on.




I think internal radiative forcing is possible, it sounds so. And I think Spencer's right that we need more work on it, but I can't help but feel that all the palaeoclimate and observational estimate for a higher climate sensitivity makes it more an academic interest. And I'm not sure what patterns of warming you'd expect, what we've seen so far is pretty consistent with greenhouse driven warming.


*he might throw out some decoys first to waste time.

2011-02-03 21:27:18

It's just a trick, as usual. He's trying to put back the null hypothesis after Trenberth talk. Why doesn't he show any peer review paper with a natural cycle coherent with recent warming? Because there's none, or he'd show it. Unless he wants to say that a natural cycle may have the hockey stick shape. People found pseudo-cycles but either they're small or they are not quantifiable in terms of global temperature (fish catch, river flow, etc.); nothing comparable to the blade of the hockey stick.

So, if you want to write a post on this do not take the challenge up but show the trick. The narrative should be as if you're seriously looking for a cycle in the temperature reconstructons. And use irony, it hurts more than anything else.

Suggestions for the title:
looking for the cycle
chasing the cycle
the impossible cycle
the immaginary cycle

2011-02-04 02:33:01
Mark Richardson

I personally think Roy's onto something. And there is a small chance that he's right and that it's relevant today (which pretty much tallies with the IPCC <5% chance sensitivity is below 1.5 C).



But if he is right about just how important it is, why don't we see much lower sensitivity in the past?

2011-02-04 03:44:20
Dana Nuccitelli

My first thought is - if the warming isn't anthropogenic, where is all the energy from the increased greenhouse effect going?  Does Spencer think radiative transfer models are wrong?  I suppose we then return to the theory that CO2 is having a small effect because climate sensitivity is low, which returns us to Mark's question - why wasn't it lower in the past if it's low now?

Can Spencer's internal variability hypothesis explain the cooling of the upper atmosphere, by the way?

My next thought is that there's not a single study, but rather it's the full body of evidence taken together.  You've got all the anthropogenic fingerprints, radiative transfer theory, spectral measurements, and many lines of evidence that climate sensitivity isn't low.  Asking for one study seems like a convenient excuse to ignore the full body of evidence.

2011-02-04 05:44:06
Rob Painting

Wow, we can pump billions of tonnes of CO2 into the atmosphere each year and it doesn't increase the Greenhouse Effect. Thanks Roy Spencer!. Says a lot when the "skeptic" darlings have to stoop to this. All this freaky weather is giving them the jitters eh?.

We have to turn this around on Spencer. Like Riccardo says, where's the evidence it's natural cycles?. And why doesn't adding an extra third of CO2 cause any warming, when physics says it should?. How about after we puncture his nonsense we throw down a counter-challenge, time for Spencer to play fetch.

2011-02-04 06:03:19how to handle the gauntlet
Dana Nuccitelli

So is this something we would want to hold off on until we do a series on Spencer (assuming we do), or would we want to respond sooner because he's thrown down the gauntlet?  I'd vote for the latter.

I wouldn't mind drafting up a post on this one, since I've done the advanced rebuttals quantifying anthropogenic warming and on the anthropogenic 'fingerprints'.  But if somebody else wants to take it, feel free.  If I were to do it, I'd need help with Spencer's internal forcing hypothesis.  Like the answer to whether it could explain the cooling upper atmosphere.

2011-02-04 06:18:51


I agree with dana's point that what makes the GHE explanation convincing is that it's consistent with the full range of evidence that we have: You don't need to do "special pleading" to explain why something that boosts your theory in one place isn't allowed to kill it somewhere else: the theory is coherent. Complicated, but coherent.

Whereas it should be pointed out that Spencer has phrased his challenge as a requirement to prove a negative, a famously difficult thing to do: "What is the ironclad proof that use of cellphones DOESN'T cause cancer (to some arbitrarily small degree)?"  "Where is the rock-solid proof that black cats ARE NOT bad luck?" You can't do it; nobody can.

All you can do is point out that:

- there is no experimental support for these ideas; and that

- there is no sensible theory that suggests a mechanism for them.


If there is a "null hypothesis", it's the one that requires the least amount of variance from what the rest of the evidence indicates.


2011-02-04 06:50:52null hypothesis
Dana Nuccitelli

Yes a key to this rebuttal will be discussing what the null hypothesis should be.  Spencer thinks it should be that the observed warming is just natural.  However, given the mounds of support for the AGW theory, there's a strong case to be made that the null hypothesis should be that humans are driving the current warming.  I believe that was Trenberth's point?

Regarding fingerprints, what about more warming at night than day?  For the internal forcing hypothesis where cloud cover changes are driving temperature changes, it seems to me like you would expect more warming during the day, when clouds are reflecting less sunlight.  At night the albedo effect is minimal.

We should make a table of the empirical observations that AGW can explain and internal forcing can't.

For reference, Spencer and Braswell (2010) suggests a mechanism of "a myriad of processes" resulting in "non-feedback cloud fluctuations", causing an "internal radiative forcing".  In his blog comments, Spencer proposes "1% or 2% changes in cloud cover, which can can cause global warming or global cooling, due to circulation changes." 

He then asks "How do YOU explain the Medieval Warm Period? Too many SUVs? Or the Little Ice Age? Too few SUVs?".  Just thought that was worth mentioning. 

2011-02-04 09:38:03

The natural cycle is not specified, could be anything, even something unknown. We cannot use the fingerprints against an unknown/unspecified natural cycle. Do not fall in his trap, the challenge is ill posed and if we take it as it is formulated we can only loose.
2011-02-04 09:45:42clouds
Dana Nuccitelli

I just updated my last comment Riccardo - when pushed to explain the physical mechanism for the internal forcing, Spencer generally resorts to "some unknown factor causing cloud changes".  So if cloud changes are inconsistent with empirical observations (i.e. cooling upper atmosphere and nights warming faster), that's worth discussing.

I see it as a multi-faceted approach.  1) null hypothesis should be AGW due to the preponderance of supporting evidence.  2) discuss the evidence supporting AGW - how it's quantified, fingerprints, sensitivity.  3) fingerprints are inconsistent with Spencer's cloud hypothesis.

2011-02-04 11:07:53


This is Tamino's take:

"Show me one peer-reviewed paper that has ruled out leprechauns as the cause of most of the recent warming in the thermometer record."

Show me one peer reviewed paper that has ruled out that God created the universe and the earth a few millennia ago and made them look like they're older.

Dana, you cannot win, you cannot show that somenthing (intentionally) unspecified does not cause warming. The risk is that people will belive that natural variability can't be ruled out. Irony is the best response. The only other thing we could do is list all the known modes of variability and one by one show they can't explain the warming. But, again, I don't think we should take Spencer challenge seriously, he has been dishonest.

2011-02-04 11:28:33
Dana Nuccitelli
I don't think it's about winning - I think this is a good opportunity to once again show the strength of the scientific evidence supporting AGW, and also point out that it doesn't support Spencer's pet hypothesis.  We can't prove Spencer wrong, but we can show that he's on weak scientific footing.  And the null hypothesis discussion is also worth having, because 'skeptics' are always saying it's not their responsibility to disprove AGW.  If AGW is the null hypothesis, then the onus is on them.
2011-04-04 10:01:47Spencer responds to criticisms - by not responding


In a post on his blog - Roy Spencer writes he will not respond to criticisms on blog media.

- In the meantime, I will not be wasting much time addressing blog criticisms of my work. The peer-reviewed literature is where I must focus my attention.

Perhaps apart from few articles on his blog as well, where he can be blessed by his followers. Spencer writes:

- Thanks for the moral support, everyone. Sometimes I wonder whether it is worth the effort, but I manage to keep going, anyway.

What a hypocrite.

2011-04-04 12:04:07Hypocrite?
Glenn Tamblyn


Perhaps not so much hypocrite as believer. I think he is caught up in the underlying psychology that "it couldn't be us. IT JUST COULDN'T BE! So it must be something else". Interesting problem. How do you get the deniers to actually confront and express their underlying psychological drivers?