Sunday, November 01, 2015

On the Hiatus in Satellite Temperatures

Carl Mears, of the RSS satellite group, Sept 2014:
"Does this slow-down in the warming mean that the idea of anthropogenic global warming is no longer valid?  The short answer is ‘no’.  The denialists like to assume that the cause for the model/observation discrepancy is some kind of problem with the fundamental model physics, and they pooh-pooh any other sort of explanation.  This leads them to conclude, very likely erroneously, that the long-term sensitivity of the climate is much less than is currently thought.

"The truth is that there are lots of causes besides errors in the fundamental model physics that could lead to the model/observation discrepancy.  I summarize a number of these possible causes below.  Without convincing evidence of model physics flaws (and I haven’t seen any), I would say that the possible causes described below need to be investigated and ruled out before we can pin the blame on fundamental modelling errors."

31 comments:

Unknown said...

I agree with Dr. Mears that the hiatus doesn't disprove anthropogenic global warming. There are physical reasons why adding CO2 to the atmosphere causes warming. Furthermore, despite the hiatus, the land-based temperature record shows that warming has been faster since 1960 or so, when atmospheric CO2 grew rapidly.

Unfortunately, he weakens a useful article by throwing in a dumb insult -- viz., "The denialists really like to fit trends starting in 1997, so that the huge 1997-98 ENSO event is at the start of their time series, resulting in a linear fit with the smallest possible slope." Dr. Mears doesn't say who these "denialists" are, nor does he tell the reader how he knows what they really like. I follow a number of skeptics and they don't make this mistake. Dr. Mears offers no evidence that all or most "denialists" like to use a cherry-picked trend.

Also, "denialist" or "climate denier" is an insulting term, because it's modeled on "Holocaust denier". Dr. Mears' statement insults a group of people by using a offensive term and making an unjustified, prejudiced insult. It's akin to saying, "The N-words are shiftless" or "The k*kes" are money-grubbing". In short, this particular comment shows Dr. Mears in a bad light.

Cheers
David in Cal

Steve said...

If you want to dispute basic science going back over 150 years then "Climate Denier" seems a pretty accurate descriptor. It has nothing to do with "Holocaust Denial".

But, I never use the term in online discussions because it gives an easy opportunity for people to change the subject. Consequently, I use the term Climate "Skeptic". The quotes indicate that in my opinion they are not genuinely skeptical but it avoids semantic discussions, after all, it is the science that is at stake, not definitions.

The claim of a "hiatus", "pause" whatever was always a nonsense. Short term trends with carefully picked starting dates can prove anything in a noisy data set. For example, the decadal trend for the last seven years (2008 - 2015 NOAA) is 0.3. I remember some years ago watching part of a talk by Pat Michaels to a Heartland audience warning them about placing emphasis on the "pause". He said that the argument would come back to bite them. And is has. It is really amusing to watch the desperate attempts of some people to hang on to this theme as the evidence mounts to the silliness of "pause" claims.

Unknown said...

The word "dispute" has more than one meaning. As a transitive verb, dictionary.com says it means
"3. to argue or debate about; discuss"
"4. to argue against; call in question: to dispute a proposal".

Steve, here are several examples of "disputing" climate change, in one sense of the word or another. Your comment leaves it unclear as to which positions you’re criticizing.
In your opinion, which of these represent unreasonable or "denier" positions?

1. Debating or discussing the true value of climate sensitivity. (Yes, the IPCC scientists "dispute" climate change, in one sense of the word.)

2. Saying that the various models and predictions are uncertain. (E.g., the latest IPCC report says, "there is high confidence that Equililbrium Climate Sensitivity is extremely unlikely less than 1°C and medium confidence that the ECS is likely between 1.5°C and 4.5°C and very unlikely greater than 6°C.")

3. Saying that no reliable predictions can be made, because the various negative and positive feedbacks are not well-understood and natural warming and cooling are not well-understood.

4. Saying that the IPCC models are essentially fraudulent. (E.g., Freeman Dyson has a claim to being Einstein’s successor as the smartest physicist in the world. He says the models are “full of fudge factors”.)

5. Saying that there's no evidence at all that man's activity causes global warming.

6. Saying that the planet hasn’t been warming.

My answer would be #5 and #6 only. But, the term “denier” is thrown about broadly. It’s an all-purpose insult.


Cheers
David in Cal

David Appell said...

Unknown wrote:
"Yes, the IPCC scientists "dispute" climate change, in one sense of the word."

No, they don't. They recognize that current science and computing power does not allow calculation of an exact value for climate sensivity -- if an exact value even exists, which is unlikely -- and that it has a margin of error.

David Appell said...

Unknown wrote:
"Saying that the various models and predictions are uncertain."

All models have uncertainties. All scientific calculations have uncertainties.

"3. Saying that no reliable predictions can be made, because the various negative and positive feedbacks are not well-understood and natural warming and cooling are not well-understood."

Predictions can't be made, even in principle. Only projections, based on assumptions about future energy use, none of which will be entirely right.

"Saying that the IPCC models are essentially fraudulent. (E.g., Freeman Dyson has a claim to being Einstein’s successor as the smartest physicist in the world. He says the models are “full of fudge factors”.)"

Dyson isn't the smartest scientist in the world. By far. And here's something he actually said:

“[m]y objections to the global warming propaganda are not so much over the technical facts, about which I do not know much, but it’s rather against the way those people behave and the kind of intolerance to criticism that a lot of them have.”

https://en.wikipedia.org/wiki/Freeman_Dyson

Unknown said...

David, when you mention something Dyson "actually" said, do you mean to imply that he didn't actually say the thing about fudge factors? I found his comment in an article from the Newark Star Ledger.

"I just think they don’t understand the climate," [Dyson] said of climatologists. "Their computer models are full of fudge factors." See http://blog.nj.com/njv_paul_mulshine/2013/04/climatologists_are_no_einstein.html

BTW that article refers to Dyson as Einstein's successor.

I've had a lot of experience with the kind of fudge factors Dyson describes. E.g., suppose a climatologist believes that clouds have an effect, but s/he doesn't have enough data to base the the clouds' effect on measured values. So, s/he makes a guess or judgment about how to reflect the clouds' effect in the model. This guess is a fudge factor. Even worse is what usually happens in practice. Suppose the model produces a result that seems unreasonable to the climatologist. There's a big temptation to go back and try different guesses about the clouds' effect, until s/he gets an answer that seems reasonable.

You may be right about Equililbrium Climate Sensitivity not having an exact value. I thought it was assumed or believed to be a fixed number. I thought its range of values measured only the scientists' uncertainty. If ECS is a variable, then the range of values would also measure how ECS varies over time.

I'm unclear about the difference in meaning of "projection" vs. "prediction". In ordininary English they're synonyms. The real question is whether the prediction or projection is reliable enough to base a given policy on.

David, as you say, all models have uncertainties. So, the question is, How large are the uncertainties? Even if you throw out Dyson's point, the IPCC scientists admit that their uncertainties are very large. IPCC 5 says, "there is high confidence that Equililbrium Climate Sensitivity is extremely unlikely less than 1°C and medium confidence that the ECS is likely between 1.5°C and 4.5°C and very unlikely greater than 6°C."

First of all, having "high confidence" of a statement that includes probabilities and confidence levels within it doesn't make sense. You can't have high confidence of medium confidence of something. Set the high confidence phrase aside. IPCC says Equililbrium Climate Sensitivity is extremely unlikely to be less than 1°C and medium confidence that the ECS is likely between 1.5°C and 4.5°C and very unlikely greater than 6°C.

A range of 1°C to 6°C is enormous. If 1°C is right, we don't have to do anything about global warming, at least not for many decades. We have plenty of time to gather more data, improve our models, and decide what to do. If 6°C is right, civilization as we know it is coming to an end. The fixes propounded by the EPA and the UN aren't nearly enough to save us from disaster. More radical action is essential, even if such action would cause many deaths.

Furthermore, the IPCC isn't even sure that ECS lies within the range of 1°C to 6°C. They set no bounds at all on what the true value might be.

Cheers
David in Cal

Unknown said...

"Freeman Dyson has a claim to being Einstein’s successor as the smartest physicist in the world. He says the models are “full of fudge factors”."

Since many younger physicists thought that Einstein wasted the last 30 years of his life and made no significant contribution to physics from 1925 onwards, claiming to be his successor does not confer on Dyson the blessing of being perpetually correct.

Personally, I would argue that the second-most important physicist of the 20th century was Richard Feynman who did collaborate with Dyson over one phase of his career.

And Dyson has made no contribution to atmospheric or climate physics - ever. And he admits to "not knowing much about the technical facts". His comments are from the periphery of climate science, and are more magnified by the denial echo-chamber than they deserve.

https://en.wikipedia.org/wiki/Freeman_Dyson#Climate_change

David Appell said...

David: I don't know what Dyson meant by "fudge factors." Probably parametrizations. If he has a better way of handling clouds, he should write some papers about it and show how it's done.

You can't look at a model description like this and say clouds are just a fudge factor -- it's a good bit more sophisticated than that. This is the kind of technical stuff Dyson admits he doesn't know.

MPI-Report No. 349 - E. Roeckner, G. Bäuml, L. Bonaventura, R. Brokopf, M. Esch, M. Giorgetta, S. Hagemann, I. Kirchner, L. Kornblueh, E. Manzini, A. Rhodin, U. Schlese, U. Schulzweida, A. Tompkins (2003): The atmospheric general circulation model ECHAM 5. PART I: Model description.

http://www.mpimet.mpg.de/fileadmin/publikationen/Reports/max_scirep_349.pdf
via
http://www.mpimet.mpg.de/en/science/models/echam.html

David Appell said...

"BTW that article refers to Dyson as Einstein's successor."

That just shows the ignorance of the writer.

There is no reason to think ECS is a fixed number. It's probably different for the second doubling of CO2 than the first (see Ed Hawkins' Climate Lab), and it's probably path dependent, depending on the time series of emitted GHGs and aerosols.

A world with no aerosol emissions obviously has a different ECS than one with aerosol emissions.

The IPCC gives a likely value of 1.5-4.5 C. Everyone knows this is a range, and it may be the best than can be done.

We will have to make decisions about what to do about climate change in the face of considerable uncertainty, with risks ahead. Even unknown risks. Do you want to risk an ECS of 4.5 C? Then do nothing and you might get it.

But humans make such decisions all the time.

Unknown said...

It all comes down to who you believe, doesn't it? The IPCC scientists have many different models. I haven't gone through each of them to determine for myself whether any inputs or relationships are based on solid data and which ones are judgments. I suspect the same is true of David Appell and Unknown 11:00 AM.

People more knowledgable than I who have looked at the models say that some of the input and model structure is judgmental. I tend to believe them. One reason is that AFAIK no climate scientist has denied that some of his or her model inputs were judgments.

Unknown said...

Do you want to risk an ECS of 4.5 C? Then do nothing and you might get it.

Taking this risk is the policy of Obama and of the UN. Their proposed solutions would have only a relatively minor impact on CO2 emissions. If their proposals are adopted and (big assumption) if each country fulfills its commitment, then atmospheric CO2 will continue its rapid increase.

Anyone who thinks ECS is 4.5 C should be furious at the UN for tricking us with a plan that won't save use from disaster.

Unknown said...

The last two comments were from me.
David in Cal

David Appell said...

"Anyone who thinks ECS is 4.5 C should be furious at the UN for tricking us with a plan that won't save use from disaster."

Bull. Most people, probably you too, would never accept a plan that fully solves global warming -- it's highly unpalatable. The only realistic option is to address the problem incrementally.

David Appell said...

"One reason is that AFAIK no climate scientist has denied that some of his or her model inputs were judgments."

What climate modeler said their models were judgements?

They're based on the laws of physics, not "judgements," whatever that is supposed to mean.

Unknown said...

David, yes the UN plan may be the only politically realistic, but it's not scientifically realistic. The total feasible impact of conservation plus expanded solar and wind power cannot be enough to stop the rise of atmospheric CO2. As of today's technology, there is no scientifically realistic way to stop CO2 from continuing to rise. Well, if we did something crazy, like killing half the world's population...

Here's one of many example of judgments in climate models. Some climate experts have hypothsized that extra heat is being stored in the deep ocean. (E.g., see http://www.skepticalscience.com/Ocean-Heat-Content-And-The-Importance-Of-The-Deep-Ocean.html ) Nobody knows for sure. So, climate modelers must make a judgment of whether their models should include extra heat going into the deep ocean. Then, they must also make judgments about how much heat goes into the deep ocean, what factors affect heat going into and out of the ocean, how big each of these factors might be, etc. Look at all the judgments needed for this one aspect. A similar set of judgments are needed for water vapor and clouds. Many other judgments are also part of the models.

Cheers
David in Cal

David Appell said...

Again, no one would accept a scientifically realistic solution.

Nuclear power should be included to provide a baseline load.

"So, climate modelers must make a judgment of whether their models should include extra heat going into the deep ocean."

What are you talking about? Modelers whose the laws of physics, expressed as partial differential equations, to calculate how much atmospheric heat exchange with the ocean. They don't just pick some value and plop it in there. Jeez.

Unknown said...

Good point re nuclear power. If the world built enormous numbers of nuclear power plants, enough to pretty much replace fossil fuels for creating electricity and fuel oil, and enough to power vehicles, which had all switched to electric, then atmospheric CO2 would start going down. This nuclear power would have to be as cheap as coal and oil, or cheaper. Otherwise many countries wouldn't make the switch.

Modelers did what I said. There's a hypothesis that unmeasurable amounts of extra heat are going into the deep ocean. I showed it in the link from Skeptical Science. The IPCC climate scientists all made a judgment to leave this factor out of their models. In other words, they guessed or assumed that the amount of extra heat going into the deep oceans is zero or negligible. But, that's just their guess. They don't actually know whether extra heat is going into the deep oceans or how much.

Cheers
David in Cal

JoeT said...

David in Cal,

Modelers did not do what you said, which is to 'guess'. Rather, you made that part up. You didn't even read the Skeptical Science article correctly. You missed this part: " ... in a recent SkS post, we saw that when measurements were extended down to 1500 metres, the oceans were found to still be warming, indicating that heat is somehow finding a way down to the deep ocean." The word 'measurements' is key here.

You can find the ocean heat content here: https://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/

Data comes from CDT (conductivity-temperature-depth), bathythermographs and more recently from ARGO floats.

However, you're missing the bigger picture: Something like the PDO is not a forcing. It doesn't matter if at some times more heat goes to the lower depths and other times it's less heat. Over time, it washes out and it's the forcings that dominate.

Unknown said...

Joe T -- yes the theory is that over time the forcings will dominate. I agree that, all other things being equal, that's a plausible belief. But, it only goes so far.

1. For all we know, there may be negative or positive feedback mechanisms that intensify or offset the forcings from CO2. So the long-term warming may be different from the combination of annual forcings.

2. We don't know the magnitude of the forcing. As discussed earlier, even if you believe the IPCC, ECS could be 1 deg C or 6 deg C or even outside that range.

3. Over past times there have been enormous temparature changes due to natural causes. These are not understood. We don't know what caused the ice ages to begin or to end. We don't know why the Little Ice Age ended a few hundred years ago. We don't know why the earth warmed rapidly from 1920 to 1940, nor do we know why it cooled from 1940 to 1950. Therefore, it's quite possible that some natural processes might have a greater impact on global warming than man does, at .least for some period lasting decade or even for a century. Such ignorance discourages me from wanting to take action on CO2 emissions, especially when that action is costly and harms poor people.

Note that the Skeptical Science article says, "science is steadily coming to terms with the many ocean processes which mix heat down into the depths". That's a nice way of saying that at present science hasn't yet fully understood the many ocean processes which mix heat. So, whatever any model does with respect to these ocean processes is necessarily a judgment.

Cheers
David in Cal

JoeT said...

David in Cal,

That forcings will dominate is not a belief. Energy comes in, energy goes out. That we know pretty well. The net energy imbalance determines the warming. It's the distribution of the heat internally that may vary.

1. When you use terms like 'for all we know' then it shows you're just guessing. Most of the feedbacks are known quite well. There may be some uncertainty in the cloud feedback, but the latest data shows it to be weak and positive.

2. You are not understanding the difference between forcing and feedback. We know almost exactly what the forcing is. It's the climate sensitivity that has some uncertainty. Also, that uncertainty is not uniform as you imply when you say 'ECS could be 1 deg or 6 deg or even outside'. Rather the climate sensitivity has a fat-tailed distribution that rises steeply around 1-2, peaks around 2.5-3 and then has a long tail beyond 6. A probability distribution one would call right-skewed.

3. It's hard to believe anyone would even write this on a blog post. Seriously, you never heard of the Milankovitch cycles? It's one of the most beautiful pieces of data I've seen. You take ice core temperatures, tabulate the temperature and the approximate date, do the Fast Fourier Transform and you get the frequency of the obliquity, precession and ellipticity of the Earth's orbit. The Little Ice Age was due to volcanoes. It's all in the literature. Have you read the scientific literature or just blog posts?

"It harms poor people"? Having salt water intrude on fresh drinking water harms poor people.

Unknown said...

Actual Climate sensitivity doesn't have any distribution, at least according to climate modelers theory. It's a fixed number. I doesn't move around. It isn't 6 deg C some of the time and 1 deg C some of the time. It represents the amount of warming due to a doubling of CO2. Any probability distribution regarding climate sensitivity is merely a way of expressing the degree and range of the scientists' uncertainty about what this true value is.

This concept may be hard to understand because the climatologists present their beliefs in a confusing way. Also, it's an unusual way to discuss scientific issues. E.g., before Michaelson and Morley did their measurement, the speed of light wasn't known. But scientists didn't proclaim that the speed of light was highly likely to be in such and such a range. They certainly didn't say that the speed of light moved around. They just said they didn't yet know the speed of light.

According to the climatologists, feedback mechanisms do affect long-term warming rates. E.g., smaller polar ice caps mean less energy reflected back into space, and thus more warming. If feedbacks didn't affect the rate of warming, then sensitivity would be fixed at around 1.1 deg C. Based on science, rather than statistics, a doubling of CO2 warms the planet by 1.1 deg C. Uncertainty about the impact of feedbacks is why the climate sensitivity range is so wide. Were feedbacks fully understood, climate sensitivity would be a known, specific number.

Cheers
David in Cal

Unknown said...

Proposals to cut CO2 emissions hurt the poor in at least three ways
1. Energy costgs will rise a lot. Poor Americans pay a larger share of their income for energy.
2. Poor Americans don’t have lots of spare cash to pay the extra cost of energy.
3. Proposals put forth by Secretary of State Kerry among others would discourage poor Africans from developing fossil-fuel based energy sources. Without these, they have no way to come anywhere near the level of Western wealth. E.g., solar is nice, but it would allow you air-condition your home or to drive your SUV around.
Cheers
David in Cal

JoeT said...

You seriously don't know what you're talking about. Once again, you're just making it up as you go along. There is no 'climate modelers theory' that says it has to be a fixed number. It's not that climatologists present their 'beliefs' (as you say) in a confusing way. They present their data very clearly. It's you who is confused about what they say. Why should it be a fixed number when the feedback itself change with the temperature? I've already showed that you were wrong in your statement that you could explain the present warming trend without feedbacks. You're even wrong about the constancy of the speed of light. It changes depending on the index of refraction of the material it travels through.

This is rapidly becoming boring to me. You will, no doubt, take the last word.

Unknown said...

Good luck to you, Joe T. You were a polite and good-natured discussant.

Cheers
David in Cal

David Appell said...

"Proposals to cut CO2 emissions hurt the poor in at least three ways."

But you're not poor. So why can't you pay for clean energy?

I buy 100% green electricity from my power company. It costs me an extra $2.30 per month, or 5%.

David Appell said...

"Proposals to cut CO2 emissions hurt the poor in at least three ways
1. Energy costgs will rise a lot"

Says what?

Pollution from fossil fuels (not counting carbon pollution) costs Americans about $200 B/yr in (mostly) health care. Did you add that to your calculation?

Fossil fuels only look cheap when you get to dump your waste garbage for free.

David Appell said...

Unknown: No, again, climate sensitivity is not a fixed number. It's path dependent, and there's no reason it should be the same for the second doubling of CO2 as it was for the first doubling.

http://www.climate-lab-book.ac.uk/2015/does-climate-sensitivity-change-with-time/

David Appell said...

"If feedbacks didn't affect the rate of warming, then sensitivity would be fixed at around 1.1 deg C. Based on science, rather than statistics, a doubling of CO2 warms the planet by 1.1 deg C."

Obviously feedbacks exist, and the most prominent ones are positive.

This is the second time you've written this nonsense. You're approaching the status of a pure troll. More of that and your comments will be removed.

David Appell said...

Unknown wrote:
"Joe T -- yes the theory is that over time the forcings will dominate."

As Joe was pointing out, this is a nonsense comment.

"1. For all we know, there may be negative or positive feedback mechanisms that intensify or offset the forcings from CO2."

We know feedback mechanisms by studying paleoclimate.

"2. We don't know the magnitude of the forcing. As discussed earlier, even if you believe the IPCC, ECS could be 1 deg C or 6 deg C or even outside that range."

More nonsense. You don't even know the difference between a forcing and ECS.

"3. Over past times there have been enormous temparature changes due to natural causes. These are not understood. We don't know what caused the ice ages to begin or to end."

This is pure ignorance, David.

I'm putting you on moderation. If you can't write better comments than this, your input isn't welcome here.

David Appell said...

Sorry, I accidentally deleted this during moderation.
=========================================================
"Unknown" wrote:

David, I said that when the IPCC offers a range of sensitivity, say from 1 deg C to 6 deg C or from 1.5 deg C to 4.5 deg. C, the range is a measure of scientific uncertainty. Based on the link you provided, I will modify that statement to say that the range is primarily a measure of scientific uncertainty.

The link you provided says that sensitivity can vary over time. However, look at how small the amount of varying is. Each of the four charts shows sensitivity varying over time by amounts ranging from 0.2 to 0.4 deg C. I think it follows that when the IPCC offers a possible range of 3 deg C, from 1.5 to 4.5 deg C, or a possible range of 5 deg C, from 1 to 6 deg, only a small portion of that range represents the fact that sensitivity can change over time. I think it follows that most of the range must represent scientific uncertainty about the true value of climate sensitivity.

Maybe I have misread the IPCC position. David, is it your understanding that the IPCC thinks the true value of climate sensitivity can vary over time by as much as 3 degrees or even 5 degrees? If you read it that way, you may be right, for all I know.

Cheers
David

David Appell said...

"David, is it your understanding that the IPCC thinks the true value of climate sensitivity can vary over time by as much as 3 degrees or even 5 degrees?"

As far as I know the the IPCC does not consider the question of how ECS varies over time.