Upper Stratosphere Cooling

After a couple of months absence, I decided to take a look again at the pit of denialism and logical fallacies that is this thread on Joanne Nova’s “global warming isn’t caused by humans” blog. If you scroll down to comment #110 you’ll see I responded to someone who had asked, “Can you name a single piece of empirical evidence that man-made carbon raises temperatures?” Note, a “single piece of empirical evidence” – not numerous pieces, not proof, but just one thing.  You’ll see that I replied with, “…the cooling of the upper stratosphere.  And no, that’s not due to ozone.” Follow the link and you’ll see that cooling of the upper stratosphere is a prediction of global warming caused by increased carbon dioxide. If such a prediction were found to be true, then this would be one piece of evidence of anthropogenic global warming (AGW).

Now, Joanne Nova has a sleazy little habit, which is to wait several weeks after a comment is made, and then go in and edit in her replies/rebuttals to comments such as the one I made. I was following this discussion for at least three weeks after I made that comment, with no response from Nova. But if you look now, at some later point she edited in the following undated reply:

Yes Sceptico [sic], still waiting for you to cite any evidence that it's not due to ozone, and here's the real kicker - even if it isn't all due to ozone, that doesn't prove it's due to carbon. Argument from Ignorance rears it's head again. Just because you can rule out other things proves nothing about carbon. For someone who points out logical errors, you sure make a lot of them yourself.

I’ll come to the evidence it’s not ozone in a minute. First, though, Nova demonstrates again her total cluelessness regarding logical fallacies.  My comment was not argument from ignorance because my claim included positive evidence that the stratospheric cooling was due to CO2. By rebutting Nova’s claim that this cooling is due to ozone, I am not saying just because it’s not ozone it must be CO2; I’m just saying it’s not ozone. I had already said that cooling of the upper stratosphere is a prediction of global warming due to increased CO2. A prediction that is confirmed cannot possibly be argument from ignorance.

Ozone?

So why did I say the cooling in the upper stratosphere is not due to ozone depletion?  From the Stratospheric cooling page I linked before:

The impact of decreasing ozone concentrations is largest in the lower stratosphere, at an altitude of around 20 km, whereas increases in carbon dioxide lead to highest cooling at altitudes between 40 and 50 km (Figure 3).  All these different effects mean that some parts of the stratosphere are cooling more than others.

And they produce these graphs of cooling rates from 1980 to 1994 at different altitudes:

4. Cooling trends at different altitudes in the stratosphere.  source: Ramaswamy et al., Reviews of Geophysics, Feb. 2001.

You’ll note that actual cooling noted is confined to altitudes of 45 and 50 kilometers. I see no cooling trend on the 22 kilometer graph.  This is exactly what is predicted by AGW caused by increased CO2, but not what would be predicted by warming due to ozone depletion.  It’s not ozone. Nova still says it’s ozone.

This Is Funny

So that’s my response.  I’m not going to respond on Nova’s blog – I’m simply not going to engage with someone who will edit in her replies to my comments weeks later to make it appear that my comment was refuted and I couldn’t respond. But here’s something funny.  I had signed up at Nova’s blog to receive email notification of comments made, so I would know if I needed to reply to anyone. Somehow, that meant that (unbeknownst to her) I had gotten onto one of Nova’s email lists where she sends out desperate appeals for help from her friends when she’s out of her depth.  I know this because I received (undoubtedly by accident) the following email that Nova sent to her group on March 3rd:

Help. Sceptico and Chris are taking over. I'm chopping. I've cut out half his post so far, because it's boring me rigid that I have to explain everything to him yet again.

This is the long long long stuff below.

I'm going away for a week - flying tomorrow night. I don't want to advertise that or chris and scepticet might think they have free run. But they will unless I ban them. They are scaring off other people.

Joanne
________________________
Joanne Nova - Director
http://www.goldnerds.com.au

(“Chris” is commenter Chris Noble, who was also attempting to educate Nova’s followers.)

I called Nova on that email, and she presumably thought better of “chopping” my post or banning me, although it didn’t stop her editing in her “rebuttals” once she realized I wasn’t reading the thread any more. It did result in an uptick in the number of lame responses to my comments, including the one I replied to as detailed above.

I will have a response to Nova’s “hotspot not found” posts at some time in the future.

Comments

[Rimantas]

Oh, finally a SOLID evidence.
Oh, wait…

[Chris Noble]

Joanne reminds me of a four year old who has just learned to repeat the language that adults use.

Her belief in her own powers of logic are completely out of proportion to her capabilities. The Kruger-Dunning effect strikes again.

I called her on a ridiculous strawman argument that the IPCC predicted that the temperature will rise monotonically. She wouldn't admit that she had committed a logical fallacy. She chopped and edited my replies and finally gave me the ultimatum that I could post again if I publicly conceded that she was correct that the IPCC predicted that temperatures will increase monotonically.

I'm not going to bother to reply under those conditions.

[yakaru]

What kind of a format is that - that lets the site owner break in on your comments and answer you mid-sentence? -And without any date on it.

Scrolling through quickly I notice this too:

techskeptic: March 21st, 2009 at 3:56 am
[removed: poor reasoning and insults ]

Removed for poor reasoning?????

That sums up her attitude and aptitude perfectly.

[Dunc]

Can you name a single piece of empirical evidence that man-made carbon raises temperatures?

Why would man-made carbon behave differently to naturally-occurring carbon? A simple black-body radiation model shows that the Earth is about 33 degrees warmer than it would be without GHGs in the atmosphere - unless of course you don't believe in either the Stefan-Boltzmann Law or the Laws of Thermodynamics...

I think I've figured out what the problem with at least some of these people is - they don't actually believe that the climate is the result of the deterministic operation of the laws of physics. They confuse chaotic or ill-determined with completely unpredictable or plain old magical.

[TechSkeptic]

A simple black-body radiation model...

Stop right there. That is the problem. Not only do those folks have no idea what a model is (they think a computer program is the same as a model, one guy was actually trying to say he was familiar with modeling becuase he wrote requirements documents for scheduling software), they don't care what model says what, becuase you know....models are always wrong and simply tools of propaganda.

I think I've figured out what the problem with at least some of these people is - they don't actually believe that the climate is the result of the deterministic operation of the laws of physics.

I disagree that is what the problem is. That is a problem but not the biggest one.

Next time any of you want to debate a climate nut. Check if they think evolution is real first. Then see how a conversation about what is evidence and how predictions are made goes. My "insults" that got deleted were notes about that that. She was scared perhaps that I was exposing that religious nuttery was affecting their thinking skills.

I doubt there is much argument about that.

[Dr. T]

Some of us do not accept the THEORY (not the proof) that stratospheric cooling has any relationship to carbon dioxide concentrations. In fact, we can just as easily posit that stratospheric cooling is evidence AGAINST global warming.

Climate "science" seems to be more about bad hypotheses and worse models than it is about true science. Remember just thirty years ago when the majority of climatologists agreed that we were heading for a new ice age! Then, twenty years later, they change their minds and say "Oops, we meant global warming, not ice age. Our bad!"

I'm a chemist and a clinical pathologist, so I've got a solid science background. I read through the entire 2004 final draft report by the IPCC. It was the worst piece of pseudoscientific garbage I ever encountered (and I saw some pretty bad science as a reviewer for five different medical journals). The evidence that we're in the midst of a global warming period is so weak that the error limits encompass no temperature change. There is no evidence that carbon dioxide causes global warming. In fact, there is no evidence that any of the greenhouse warming gases cause planetary warming: what happens in a closed greenhouse will not be the same as what happens planet-wide, but most climatologists act as if the greenhouse effect is a proven effect for the planet.

I could also give a long rant about how bad the climate predicion models were in the IPCC report: the best model overestimated average temperatures in the Arctic and Antarctic regions by an average of six degrees centigrade. The model should have been discarded with that much error near the poles, but the IPCC used it to predict catastrophic ice cap melting and worldwide coastal flooding.

The fact the you, a self-proclaimed skeptic, fully bought into the global warming scan indicates that you did not thoroughly read the IPCC report, and that you have closed your eyes to opposing theories. You converted yourself from a skeptic into a dogmatist.

[TechSkeptic]

Some of us do not accept the THEORY (not the proof) that stratospheric cooling has any relationship to carbon dioxide concentrations.

Please link me to the person who says they have proof. Otherwise you are trying to create a strawman.

Remember just thirty years ago when the majority of climatologists agreed that we were heading for a new ice age

Please link me to the "majority of scientists" that thought this. By your standard, a "majority" of scientists think that the LHC will cause a black hole that will destroy the earth. Stop confusing science and media hype.

I'm a chemist and a clinical pathologist, so I've got a solid science background

and no background or expertise in climate science or the physics behind it. This doesnt make you wrong, its just irrelevant.

I read through the entire 2004 final draft report by the IPCC. It was the worst piece of pseudoscientific garbage I ever encountered

And yet you site not a single example, you just assume we should just take a pathologists word on his opinion of a long draft that had contributions from 2500 climate scientists. Lemme think which way I'm gonna go on that.

There is no evidence that carbon dioxide causes global warming.

NO evidence?.. none?. zero evidence that CO2 or other GHGs can cause warming. Never mind the corellation, never mind the absorption spectum of GHGS with respect to water. Never mind warming faster than has ever been recorded on the planet despite no particular rise in insolence. Never mind the disappearance of the 800 year lag. Never mind all those other things. you are truly going to sit there and spout "no evidence!" LOL

In fact, there is no evidence that any of the greenhouse warming gases cause planetary warming: what happens in a closed greenhouse will not be the same as what happens planet-wide, but most climatologists act as if the greenhouse effect is a proven effect for the planet.

and now here you stand on a rooftop and proclaim you utter ignorance of climate science (I knew this was coming). Please link me to the climate scientist who says the planet's climate is exactly a closed greenhouse. No, you will find instead that a greenhouse is only used as a demonstration of how the heating happens, NOT that the earth is a greenhouse. you have once again confused a media representation with actual science.

your next paragraph is a ridiculous diatribe displaying a sadly strawman proposition about how climate models (heck any model) is used. Please find me a physics based model that describes the climate of the previous 200 years as well as current ones, that do not incorporate greenhouse gas emmisions. Denialists have had 30 years to refine models to prove that out...but we see nothing. Why is that?

Oh and one more thing... is evolution the best model to describe speciation and the existence of human, or is there a better one backed up by more evidence?

[TechSkeptic]

crap sorry skeptico.. can you fixy?

[Bronze Dog]

Funny thing: That whole "majority of scientists" going on about cooling: Actually, IIRC, it was a few guys who published an article about ice ages, saying the next one's coming... 20,000 years from now. Apparently some denialist conveniently left out that number, and the rest just robotically repeated it.

[TechSkeptic]

Well there is this book...

This much hyped book came out in the 70's and is the basis of what denialists claim was "a majority of scientists" thought the earth was cooling dangerously.

Just read a review by someone who actually read it. Its pretty funny. Its kind of a joke that denialists continue to use this canard.

Do you htink our friend Dr. T actually read this book. Do you think he was able to find the pseudoscience in there? (Like such claims as the moon is moving away form the earth because gravity in the universe is weakening, lol)

There was this one book and a few papers (of the thousands published every year) that made the claim of cooling. Anyone referencing that silliness has clearly made himself out to be a dope.

here is more for you on that exact subject. RealClimate of course has an article address this also.

So the global cooling nonsense has been brought up thousands of times by denialists, and it has been answers an equal number of times, its time for them to move their poorer position forward if they can.

[Skeptico]

Techskeptic

Fixed. btw it’s /blockquote not /bockquote

Dr T:

Some of us do not accept the THEORY (not the proof) that stratospheric cooling has any relationship to carbon dioxide concentrations.

So what? Why should we care that you don’t believe it? You demonstrate your scientific naiveté by even saying “not the proof” as though that means anything. Science is never about “proof” it is about evidence. So you FAIL right out the gate.

Second, the article I linked explained why it is:

Greenhouse gases (CO2, O3, CFC) absorb infra-red radiation from the surface of the Earth and trap the heat in the troposphere.  If this absorption is really strong, the greenhouse gas blocks most of the outgoing infra-red radiation close to the Earth's surface.  This means that only a small amount of outgoing infra-red radiation reaches carbon dioxide in the upper troposphere and the lower stratosphere.  On the other hand, carbon dioxide emits heat radiation, which is lost from the stratosphere into space.  In the stratosphere, this emission of heat becomes larger than the energy  received from below by absorption and, as a result, there is a net energy loss from the stratosphere and a resulting cooling.  Other greenhouse gases, such as ozone and chlorofluorocarbons (CFC's), have a weaker impact because their concentrations in the troposphere are smaller. They do not entirely block the whole radiation in their wavelength regime so some reaches the stratosphere where it can be absorbed and, as a consequence, heat this region of the atmosphere. [My bold.]

Of course I’m sure you will now be able to explain exactly why this is wrong. Oh and “Some of us do not accept” it will not be good enough.

In fact, we can just as easily posit that stratospheric cooling is evidence AGAINST global warming.

Yes I’m sure you could “posit” it, but could you support it with evidence? And could you explain away my link that says the opposite?

Climate "science" seems to be more about bad hypotheses and worse models than it is about true science. Remember just thirty years ago when the majority of climatologists agreed that we were heading for a new ice age!

No I don’t remember that, because it didn’t happen. You are talking about the The global cooling myth – a few popular new magazines reported it but it wasn’t mainstream climate science. Unlike, say, what AGW is now.

But even if what you said was true, so what? That’s just a fallacious appeal to “science was wrong before”. Science is a series of provisional truths, backed by evidence, that are amended when better evidence is available. In other words, we have a reason to suppose scientifically supported ideas are true.  In reality, science has proved the most reliable method we know for evaluating claims and figuring out how the universe works, and that process now overwhelmingly supports the AGW theory.

I'm a chemist and a clinical pathologist, so I've got a solid science background. I read through the entire 2004 final draft report by the IPCC. It was the worst piece of pseudoscientific garbage I ever encountered (and I saw some pretty bad science as a reviewer for five different medical journals).

Well the 2,500 or so people involved in producing that report were working climate scientists, so I guess you lose. Nice attempt to appeal to authority though.

The evidence that we're in the midst of a global warming period is so weak that the error limits encompass no temperature change. There is no evidence that carbon dioxide causes global warming.

None? None at all? Thanks for clearing that up.

In fact, there is no evidence that any of the greenhouse warming gases cause planetary warming: what happens in a closed greenhouse will not be the same as what happens planet-wide, but most climatologists act as if the greenhouse effect is a proven effect for the planet.

Don’t be silly – climate scientists don’t act as if the Earth is a “closed greenhouse”.

I could also give a long rant about how bad the climate predicion models were in the IPCC report: the best model overestimated average temperatures in the Arctic and Antarctic regions by an average of six degrees centigrade. The model should have been discarded with that much error near the poles, but the IPCC used it to predict catastrophic ice cap melting and worldwide coastal flooding.

Another appeal to “science was wrong before” combined with cherry picking (denialist tactic #2).

The fact the you, a self-proclaimed skeptic, fully bought into the global warming scan indicates that you did not thoroughly read the IPCC report, and that you have closed your eyes to opposing theories. You converted yourself from a skeptic into a dogmatist.

Oh noes, I’m not a skeptic. You got me. What can I say to such a brilliant rebuttal to my arguments? I’m devastated. I guess AGW is crap then. No, the truth is, you’re the one who has been suckered into believing in pseudoscience - you still quote the global cooling myth although that was debunked years ago.

[Jimmy_Blue]

I'm a chemist and a clinical pathologist, so I've got a solid science background.

...

In fact, there is no evidence that any of the greenhouse warming gases cause planetary warming

So, I take it they never covered the electro-magnetic spectrum and water absorption bands in your chemistry or pathology classes? Does your solid science background include any modern physics? Or do you still believe in the luminiferous ether?

I suggest you go and do some research and then come back and worm your way out of this one. We can wait.

[Chris Noble]

Meanwhile the strawmen are being put up and torn down at a furious rate.

Invasion of the Zombie Strawmen
29 year trend vs IPCC "prediction"

Monckton has apparently taken the IPCC projections for global temperature in 2100 and calculated a linear rate of temperature increase from 1980. He then uses this as the IPCC "prediction" of about +4 degsC/century and compares this with the observed temperature trend from 1980 to 2009.

[Dunc]

In fact, we can just as easily posit that stratospheric cooling is evidence AGAINST global warming.

Only if you don't believe in the First Law of Thermodynamics. Heat doesn't just appear or disappear at random - it has to come from somewhere and go somewhere. A cooler stratosphere means that it must be in radiative imbalance, and there's only two possible sources (the Earth and the Sun). We know that it's not the sun, as Total Solar Irradiance hasn't changed enough to explain the observed stratospheric cooling. We also know that the surface temperature of the Earth hasn't changed enough (or indeed, in the right direction) to explain it, therefore the only possible conclusion compatible with thermodynamics is that more heat is being absorbed in the lower atmosphere.

In fact, there is no evidence that any of the greenhouse warming gases cause planetary warming:

Please explain why the surface temperature of Venus is higher than that of Mercury, without reference to the greenhouse effect. Show your working.

Why do I suspect I may as well be talking to the wall?

[[email protected]]

"I hope there is no God" Finally, an honest atheist strikes the right chord.

See:

http://thinkpoint.wordpress.com/2008/12/03/i-hope-there-is-no-god-thomas-nagel/

[TechSkeptic]

Way to stay on topic, steve.

(what a dumb post by the way)

[Martin]

Finally, an honest atheist strikes the right chord.

Now all we need is an honest theist who doesn't post his shit all over the place as if anyone gave a shit.

[Jimmy_Blue]

Dunc:

Why do I suspect I may as well be talking to the wall?

Because you suspect that the wall wouldn't try and justify it's stance on climate change science and physics with reference to its chemistry and pathology background as well as its entirely relevant participation in medical journal review boards?

On the off chance that some graffiti on the wall might actually include citations to back up its claims?

On the off chance that the wall actually knows some modern physics?

I can think of a lot of reasons why you might think talking to the wall might be more productive in this case....

[Willie Wonka]

So what about the water vapor in the cooling model that is just as likely to be from a natural source as it is human activity?

Atheists amuse me in how they are just as dogmatic as the theistic crowd, with exactly the same amount of evidence...

[Jimmy_Blue]

Willie Wonka:

How did you fit so much rubbish in such a short space?

So what about the water vapor in the cooling model that is just as likely to be from a natural source as it is human activity?

Where did I say water vapor in the atmosphere wasn't from a natural source?

If you were half as clever as you think you are you would have understood that Dr. T made a ridiculous claim (that there is no evidence greenhouse gases cause global warming) that the scientific evidence flatly contradicts - I merey pointed out that naturally occurring water vapor is a greenhouse gas - it absorbs something like 70% of incoming sunlight and is also responsible for 60% of the atmospheric absorption of thermal radiation from the Earth. Try looking at a spectral signature graph and you can see this very clearly in many cases.

The problem is that extra carbon dioxide in the air warms the atmosphere allowing it to hold more water vapor. Even you must be able to see where that is going. Right?

Atheists amuse me in how they are just as dogmatic as the theistic crowd, with exactly the same amount of evidence...

What the hell does being an atheist have to do with climatology and physics?

Atheism = lack of belief in gods. Climatology and physics = science.

Oh wait nevermind, I got it - you know sod all about any of them so threw them in together to try and sound clever. Oh well. Better luck next time.

But go on - explain how apparently knowing more about the electromagnetic spectrum than you or the illustrious Dr. T constitutes dogma. We can wait. Just like we've been waiting for Dr. T to explain how water vapor isn't a greenhouse gas and doesn't contribute to global warming.

Is it me or is the Dunning-Kruger effect becoming a more common phenomenon?

[Dunc]

Is it me or is the Dunning-Kruger effect becoming a more common phenomenon?

I don't think it's actually becoming more common, it's just that the sufferers are becoming louder and more aggressive, and they've started working in packs.

[Joseph]

I've analyzed the data myself, and there's no question (after controlling for possibly coincidental trends) that temperature fluctuations are largely driven by CO2 fluctuations.

This is a graph of detrended global temperatures and detrended cumulative CO2 emissions 10 years prior, for the last 150 years. (It would look the same if you use CO2 atmospheric concentration data instead - I just didn't have that data when I made the graph.)

That's the straight association. I've also done some more accurate modeling, based on the theoretical foundation of green house gases. That is, equilibrium temperature depends on the concentration of the GHG, logarithmically. The difference between the temperature and the equilibrium temperature should be proportional to the rate of temperature change. Based on this, I came up with this hindcast of the last 150 years. It's not that complicated.

[Gail Zawacki]

Hi, I just found this blog and I'm very glad I did! I've bookmarked it and I'm looking forward to reading past posts and comments.

The topics here are of great interest to me. I have started a blog of my own about evolution and climate, because even many of those who believe in AGW and are skeptical scientists don't seem to understand that the climate has already changed and therefore, the ecosystems that evolved to occupy the climate we had 150 years ago and for long before that simply aren't going to be able to adapt and survive.

I get so frustrated by foresters and conservationists and environmentalists talking about planting trees and saving the rainforest. It's a distraction from the real question which is how are we going to maintain human civilization in the face of mass extinction.

For a summation of my observations on this topic, please visit at

http://witsendnj.blogspot.com/2009/05/effects-of-climate-chaos.html

Any thoughts from fellow skeptics are welcome!

[TechSkeptic]

51 posts in may alone!

you are on track to beat PZ and Orac in volume alone!

[Gail Zawacki]

The month isn't over yet, either. And you must read every single one!

[Jimmy_Blue]

Well Dr. T, where did your solid science background go? Surely a scientist like you can admit a mistake after examining the evidence? Where did you go?

And Willie Wonka - all claims and still no evidence we see.

Pathetic.

[Dr. T]

Well, I see that there are a slew of non-skeptics criticizing my previous comment. The claim that we are undergoing anthropogenic global warming is extraordinary. Remember the dictum of scientific evidence: extraordinary claims require extraordinary evidence. Not half-baked models with deliberately ignored huge errors. Not selectively chosen evidence (climatologists look at ice melting on the west side of Antarctica and ignore the main body of the continent and the east side where ice has been thickening for 30 years). Not projections of local lab effects (greenhouse gases) into planetary-wide effects with no experimentation to show that the projections are valid. Not climate theories with no evidence at all (stratospheric cooling presages global warming--look at our neat equations). None of these is extraordinary evidence, and most of them are pseudoscience or outright fraud.

But, most of you will go on believing the IPCC's self-serving propaganda. After all, 2500 climatologists can't be wrong! Sure they can, if it advances their own self interest, especially in a field with so little hard evidence. Again, I challenge those of you with a good science background to study the actual IPCC report. Look at the sections on CO2 and see how little effect it has on global temperatures. Then look at how bad the climate models are at predicting just 10 years forward, yet they used one of those horrid models to predict 100 years of climate. You can also look at the ocean depth studies and note the magnitude of measurement errors and the poor correlations with polar warm periods. Then you can decide who's the better skeptic.

[Jimmy_Blue]

So Dr. T, still haven't read up on the electromagnetic spectrum or water absorption bands I see. Nevermind.

Really, was that comment any different to your first one?

[Skeptico]

Dr. T

The claim that we are undergoing anthropogenic global warming is extraordinary.

Not really. It is in keeping with basic science of why the surface of Earth is warm enough for life. It is consistent with Venus being hotter than a hot oven and Mars being cold. For it to be “extraordinary”, there would have to be some known or accepted scientific fact or theory that AGW contradicts. What theories have to be re-written if we accept AGW?

Also, I note you are unable to explain exactly why the stratospheric cooling observations do not support AGW. Like I asked.

Also, do you still believe that thirty years ago the majority of climatologists agreed that we were heading for a new ice age? Do you – yes or no?

[TechSkeptic]

Dr. T,

oh goody, you came back, ignored all the comments above, didn't defend your contention with a single link..and then wrote more stuff, again without supporting it with a single link.

Really, Dr. t, do you really think anyone here (or anywhere) is just going to take your word for it? Why not answer the simple and straightforward questions before moving on. Why not provide links to your claims? afraid?

Sadly its extremely typical.

[Howard]

September 29, 2009, 12:29 pm
Holdren’s Ice Age Tidal Wave
By John Tierney
As a long-time student of John P. Holdren’s gloomy visions of the future, like his warnings about global famines and resource shortages, I can’t resist passing along another one that has just been dug up. This one was made in 1971, long before Dr. Holdren came President Obama’s science adviser, in an essay just unearthed by zombietime (a blog that has been republishing excerpts of his past writings). In the 1971 essay, “Overpopulation and the Potential for Ecocide,” Dr. Holdren and his co-author, the ecologist Paul Ehrlich, warned of a coming ice age.

They certainly weren’t the only scientists in the 1970s to warn of a coming ice age, but I can’t think of any others who were so creative in their catastrophizing. Although they noted that the greenhouse effect from rising emissions of carbon dioxide emissions could cause future warming of the planet, they concluded from the mid-century cooling trend that the consequences of human activities (like industrial soot, dust from farms, jet exhaust, urbanization and deforestation) were more likely to first cause an ice age. Dr. Holdren and Dr. Ehrlich wrote:

The effects of a new ice age on agriculture and the supportability of large human populations scarcely need elaboration here. Even more dramatic results are possible, however; for instance, a sudden outward slumping in the Antarctic ice cap, induced by added weight, could generate a tidal wave of proportions unprecedented in recorded history.

But that would just be the beginning. Dr. Holdren and Dr. Ehrlich continued:

If man survives the comparatively short-term threat of making the planet too cold, there is every indication he is quite capable of making it too warm not long thereafter. For the remaining major means of interference with the global heat balance is the release of energy from fossil and nuclear fuels. As pointed out previously, all this energy is ultimately degraded to heat. What are today scattered local effects of its disposition will in time, with the continued growth of population and energy consumption, give way to global warming. … Again, the exact form such consequences might take is unknown; the melting of the ice caps with a concomitant 150-foot increase in sea level might be one of them.

I confess that I don’t quite understand Dr. Holdren’s particular 1971 vision of global warming — why would nuclear fuels be contributing to it? — but let’s not get bogged down in details. What interests me are not the disaster specifics but rather Dr. Holdren’s tendency to foresee worst-case situations that require new public policies. (In the 1970s, he and Dr. Ehrlich discussed controlling population by giving sweeping powers to a new “Planetary Regime.”) I’ve previously written about criticism that a climate-change report from the White House and federal agencies exaggerates the threat of natural disasters. Does Dr. Holdren have a worst-case bias in his interpretation of data?