Coyote Blog

For years, readers of this site know that I have argued that:

• CO2 is indeed a greenhouse gas, and since man is increasing its atmospheric concentration, there is likely some anthropogenic contribution to warming
• Most forecasts, including those of the IPCC, grossly exaggerate temperature sensitivity to CO2 by assuming absurd levels of net positive feedback in the climate system
• Past temperature changes are not consistent with high climate sensitivities

Recently, there have been a whole spate of studies based on actual observations rather than computer models that have been arriving at climate sensitivity numbers far below the IPCC number.   While the IPCC settled on 3C per doubling of CO2, it strongly implied that all the risk was to the upside, and many other prominent folks who typically get fawning attention in the media have proposed much higher numbers.

In fact, recent studies are coming in closer to 1.5C - 2C.  I actually still think these numbers will turn out to be high.  For several years now my money has been on a number from 0.8 to 1 C, sensitivity numbers that imply a small amount of negative feedback rather than positive feedback, a safer choice in my mind since most long-term stable natural systems are dominated by negative feedback.

Anyway, in an article that was as surprising as it is welcome, NY Times climate writer Andy Revkin has quite an article recently, finally acknowledging in the paper of record that maybe those skeptics who have argued for alower sensitivity number kind of sort of have a point.

“Worse than we thought” has been one of the most durable phrases lately among those pushing for urgent action to stem the buildup of greenhouse gases linked to global warming.

But on one critically important metric — how hot the planet will get from a doubling of the pre-industrial concentration of greenhouse gases, a k a “climate sensitivity” — someclimate researchers with substantial publication records are shifting toward the lower end of the warming spectrum.

By the way, this is the only metric that matters.  All the other BS about "climate change" and "dirty weather" are meaningless without warming.  CO2 cannot change the climate  or raise sea levels or any of that other stuff by any mechanism we understand or that has even been postulated, except via warming.  Anyway, to continue:

There’s still plenty of global warming and centuries of coastal retreats in the pipeline, so this is hardly a “benign” situation, as some have cast it.

But while plenty of other climate scientists hold firm to the idea that the full range of possible outcomes, including a disruptively dangerous warming of more than 4.5 degrees C. (8 degrees F.), remain in play, it’s getting harder to see why the high-end projections are given much weight.

This is also not a “single-study syndrome” situation, where one outlier research paper is used to cast doubt on a bigger body of work — as Skeptical Science asserted over the weekend. That post focused on the as-yet-unpublished paper finding lower sensitivity that was inadvisedly promoted recently by the Research Council of Norway.

In fact, there is an accumulating body of reviewed, published researchshaving away the high end of the range of possible warming estimates from doubled carbon dioxide levels. Chief among climate scientists critical of the high-sensitivity holdouts is James Annan, an experienced climate modeler based in Japan who contributed to the 2007 science report from the Intergovernmental Panel on Climate Change. By 2006, he was already diverging from his colleagues a bit.

The whole thing is good.  Of course, for Revkin, this is no excuse to slow down all the actions supposedly demanded by global warming, such as substantially raising the price and scarcity of hydrocarbons.  Which to me simply demonstrates that people who have been against hydrocarbons have always been against them as an almost aesthetic choice, and climate change and global warming were mere excuses to push the agenda.  After all, as there certainly are tradeoffs to limiting economic growth and energy use and raising the price of energy, how can a reduction in postulated harms from fossil fuels NOT change the balance point one chooses in managing their use?

PS-  I thought this was a great post mortem on Hurricane Sandy and the whole notion that this one data point proves the global warming trend:

In this case several factors not directly related to climate change converged to generate the event. On Sandy’s way north, it ran into a vast high-pressure system over Canada, which prevented it from continuing in that direction, as hurricanes normally do, and forced it to turn west. Then, because it traveled about 300 miles over open water before making landfall, it piled up an unusually large storm surge. An infrequent jet-stream reversal helped maintain and fuel the storm. As if all that weren’t bad enough, a full moon was occurring, so the moon, the earth, and the sun were in a straight line, increasing the moon’s and sun’s gravitational effects on the tides, thus lifting the high tide even higher. Add to this that the wind and water, though not quite at hurricane levels, struck an area rarely hit by storms of this magnitude so the structures were more vulnerable and a disaster occurred.

The last one is a key for me -- you have cities on the Atlantic Ocean that seemed to build and act as if they were immune from ocean storms.  From my perspective growing up on the gulf coast, where one practically expects any structure one builds on the coast to be swept away every thirty years or so, this is a big contributing factor no one really talks about.

She goes on to say that rising sea levels may have made the storm worse, but I demonstrated that it couldn't have added more than a few percentage points to the surge.

Russ Roberts over at Cafe Hayek quotes from a Cathy O’Neill review of Nate Silvers recent book:

Silver chooses to focus on individuals working in a tight competition and their motives and individual biases, which he understands and explains well. For him, modeling is a man versus wild type thing, working with your wits in a finite universe to win the chess game.

He spends very little time on the question of how people act inside larger systems, where a given modeler might be more interested in keeping their job or getting a big bonus than in making their model as accurate as possible.

In other words, Silver crafts an argument which ignores politics. This is Silver’s blind spot: in the real world politics often trump accuracy, and accurate mathematical models don’t matter as much as he hopes they would....

My conclusion: Nate Silver is a man who deeply believes in experts, even when the evidence is not good that they have aligned incentives with the public.

Distrust the experts

Call me “asinine,” but I have less faith in the experts than Nate Silver: I don’t want to trust the very people who got us into this mess, while benefitting from it, to also be in charge of cleaning it up. And, being part of the Occupy movement, I obviously think that this is the time for mass movements.

Like Ms. O'Neill, I distrust "authorities" as well, and have a real problem with debates that quickly fall into dueling appeals to authority.  She is focusing here on overt politics, but subtler pressure and signalling are important as well.  For example, since "believing" in climate alarmism in many circles is equated with a sort of positive morality (and being skeptical of such findings equated with being a bad person) there is an underlying peer pressure that is different from overt politics but just as damaging to scientific rigor.  Here is an example from the comments at Judith Curry's blog discussing research on climate sensitivity (which is the temperature response predicted if atmospheric levels of CO2 double).

While many estimates have been made, the consensus value often used is ~3°C. Like the porridge in “The Three Bears”, this value is just right – not so great as to lack credibility, and not so small as to seem benign.

Huybers (2010) showed that the treatment of clouds was the “principal source of uncertainty in models”. Indeed, his Table I shows that whereas the response of the climate system to clouds by various models varied from 0.04 to 0.37 (a wide spread), the variation of net feedback from clouds varied only from 0.49 to 0.73 (a much narrower relative range). He then examined several possible sources of compensation between climate sensitivity and radiative forcing. He concluded:

“Model conditioning need not be restricted to calibration of parameters against observations, but could also include more nebulous adjustment of parameters, for example, to fit expectations, maintain accepted conventions, or increase accord with other model results. These more nebulous adjustments are referred to as ‘tuning’.”  He suggested that one example of possible tuning is that “reported values of climate sensitivity are anchored near the 3±1.5°C range initially suggested by the ad hoc study group on carbon dioxide and climate (1979) and that these were not changed because of a lack of compelling reason to do so”.

Huybers (2010) went on to say:

“More recently reported values of climate sensitivity have not deviated substantially. The implication is that the reported values of climate sensitivity are, in a sense, tuned to maintain accepted convention.”

Translated into simple terms, the implication is that climate modelers have been heavily influenced by the early (1979) estimate that doubling of CO2 from pre-industrial levels would raise global temperatures 3±1.5°C. Modelers have chosen to compensate their widely varying estimates of climate sensitivity by adopting cloud feedback values countering the effect of climate sensitivity, thus keeping the final estimate of temperature rise due to doubling within limits preset in their minds.

There is a LOT of bad behavior out there by models.  I know that to be true because I used to be a modeler myself.  What laymen do not understand is that it is way too easy to tune and tweak and plug models to get a preconceived answer -- and the more complex the model, the easier this is to do in a non-transparent way.  Here is one example, related again to climate sensitivity

When I looked at historic temperature and CO2 levels, it was impossible for me to see how they could be in any way consistent with the high climate sensitivities that were coming out of the IPCC models.  Even if all past warming were attributed to CO2  (a heroic assertion in and of itself) the temperature increases we have seen in the past imply a climate sensitivity closer to 1 rather than 3 or 5 or even 10  (I show this analysis in more depth in this video).

My skepticism was increased when several skeptics pointed out a problem that should have been obvious.  The ten or twelve IPCC climate models all had very different climate sensitivities — how, if they have different climate sensitivities, do they all nearly exactly model past temperatures?  If each embodies a correct model of the climate, and each has a different climate sensitivity, only one (at most) should replicate observed data.  But they all do.  It is like someone saying she has ten clocks all showing a different time but asserting that all are correct (or worse, as the IPCC does, claiming that the average must be the right time).

The answer to this paradox came in a 2007 study by climate modeler Jeffrey Kiehl.  To understand his findings, we need to understand a bit of background on aerosols.  Aerosols are man-made pollutants, mainly combustion products, that are thought to have the effect of cooling the Earth’s climate.

What Kiehl demonstrated was that these aerosols are likely the answer to my old question about how models with high sensitivities are able to accurately model historic temperatures.  When simulating history, scientists add aerosols to their high-sensitivity models in sufficient quantities to cool them to match historic temperatures.  Then, since such aerosols are much easier to eliminate as combustion products than is CO2, they assume these aerosols go away in the future, allowing their models to produce enormous amounts of future warming.

Specifically, when he looked at the climate models used by the IPCC, Kiehl found they all used very different assumptions for aerosol cooling and, most significantly, he found that each of these varying assumptions were exactly what was required to combine with that model’s unique sensitivity assumptions to reproduce historical temperatures.  In my terminology, aerosol cooling was the plug variable.

By the way, this aerosol issue is central to recent work that is pointing to a much lower climate sensitivity to CO2 than has been reported in past IPCC reports.

Kevin Drum posts this chart with a straight face as "proof" that sea level rise is out-pacing forecasts.

I don't really think I need to even point out the problem to most of my readers, but you can see the differences in ending value is because the starting values are different.  Likely the two are drawing from different data sources with a shifted zero value.  The slopes are the same, confirmed by the fact that the 3.2 mm trend per year is well within the IPCC forecast range that was centered, if I remember right, around 3.3 mm per year.  It is also well under Al Gore's forecast, which was for 20 feet by 2100, or about 61 mm per year.

... and it was fun to see my charts in it!  The lecture is reprinted here (pdf) or here (html).  The charts I did are around pages 6-7 of the pdf, the ones showing the projected curve of global warming for various climate sensitivities, and backing into what that should imply for current warming.  In short, even if you don't think warming in the surface temperature record is exaggerated, there still has not been anywhere near the amount of warming one would expect for the types of higher sensitivities in the IPCC and other climate models.  Warming to date, even if not exaggerated and all attributed to man-made and not natural causes, is consistent with far less catastrophic, and more incremental, future warming numbers.

These charts come right out of the IPCC formula for the relationship between CO2 concentrations and warming, a formula first proposed by Michael Mann.  I explained these charts in depth around the 10 minute mark of this video, and returned to them to make the point about past warming around the 62 minute mark.   This is a shorter video, just three minutes, that covers the same ground.  Watching it again, I am struck by how relevant it is as a critique five years later, and by how depressing it is that this critique still has not penetrated mainstream discussion of climate.  In fact, I am going to embed it below:

The older slides Ridley uses, which are cleaner (I went back and forth on the best way to portray this stuff) can be found here.

By the way, Ridley wrote an awesome piece for Wired more generally about catastrophism which is very much worth a read.

I know I hammer this home constantly, but it is often worth a reminder.  The issue in the scientific debate over catastrophic man-made global warming theory is not whether CO2 is a greenhouse gas, or even the approximate magnitude of warming from CO2 directly, but around feedbacks.   Patrick Moore, Greenpeace founder, said it very well:

What most people don't realize, partly because the media never explains it, is that there is no dispute over whether CO2 is a greenhouse gas, and all else being equal would result in a warming of the climate. The fundamental dispute is about water in the atmosphere, either in the form of water vapour (a gas) or clouds (water in liquid form). It is generally accepted that a warmer climate will result in more water evaporating from the land and sea and therefore resulting in a higher level of water in the atmosphere, partly because the warmer the air is the more water it can hold. All of the models used by the IPCC assume that this increase in water vapour will result in a positive feedback in the order of 3-4 times the increase in temperature that would be caused by the increase in CO2 alone.

Many scientists do not agree with this, or do not agree that we know enough about the impact of increased water to predict the outcome. Some scientists believe increased water will have a negative feedback instead, due to increased cloud cover. It all depends on how much, and a t what altitudes, latitudes and times of day that water is in the form of a gas (vapour) or a liquid (clouds). So if  a certain increase in CO2 would theoretically cause a 1.0C increase in temperature, then if water caused a 3-4 times positive feedback the temperature would actually increase by 3-4C. This is why the warming predicted by the models is so large. Whereas if there was a negative feedback of 0.5 times then the temperature would only rise 0.5C.

My slightly lengthier discussions of this same issue are here and here.

My Forbes column is up this week.  I really did not want to write about climate, but when Forbes conctributor Steve Zwick wrote this, I had to respond

We know who the active denialists are – not the people who buy the lies, mind you, but the people who create the lies.  Let’s start keeping track of them now, and when the famines come, let’s make them pay.  Let’s let their houses burn.  Let’s swap their safe land for submerged islands.  Let’s force them to bear the cost of rising food prices.

They broke the climate.  Why should the rest of us have to pay for it?

The bizarre threats and ad hominem attacks have to stop.  Real debate is necessary based on an assumption that our opponents may be wrong, but are still people of good will.  And we need to debate what really freaking matters:

Instead of screwing around in the media trying to assign blame for the recent US heat wave to CO2 and threatening to burn down the houses of those who disagree with us, we should be arguing about what matters.  And the main scientific issue that really matters is understanding climate feedback.  I won't repeat all of the previous posts (see here and here), but this is worth repeating:

Direct warming from the greenhouse gas effect of CO2 does not create a catastrophe, and at most, according to the IPCC, might warm the Earth another degree over the next century.  The catastrophe comes from the assumption that there are large net positive feedbacks in the climate system that multiply a small initial warming from CO2 many times.  It is this assumption that positive feedbacks dominate over negative feedbacks that creates the catastrophe.  It is telling that when prominent supporters of the catastrophic theory argue the science is settled, they always want to talk about the greenhouse gas effect (which most of us skeptics accept), NOT the positive feedback assumption.  The assumption of net positive climate feedback is not at all settled -- in fact there is as much evidence the feedback is net negative as net positive -- which may be why catastrophic theory supporters seldom if ever mention this aspect of the science in the media.

I said I would offer a counter-proposal to Mr. Zwick's that skeptics bear the costs of climate change.  I am ready to step up to the cost of any future man-made climate change if Mr. Zwick is ready to write a check for the lost economic activity and increased poverty caused by his proposals.  We are at an exciting point in history where a billion people, or more, in Asia and Africa and Latin America are at the cusp of emerging from millenia of poverty.  To do so, they need to burn every fossil fuel they can get their hands on, not be forced to use rich people's toys like wind and solar.  I am happy to trade my home for an imaginary one that Zwick thinks will be under water.  Not only is this a great way to upgrade to some oceanfront property, but I am fully confident the crazy Al Gore sea level rise predictions are a chimera, since sea levels have been rising at a fairly constant rate since the end of the little ice age..  In return, perhaps Mr. Zwick can trade his job for one in Asia that disappears when he closes the tap on fossil fuels?

I encourage you to read it all, including an appearance by the summer of the shark.

Cross posted from Climate Skeptic

This quote from Michael Mann [of Hockey Stick fame] is a great example of two common rhetorical tactics of climate alarmists:

And so I think we have to get away from this idea that in matters of science, it's, you know, that we should treat discussions of climate change as if there are two equal sides, like we often do in the political discourse. In matters of science, there is an equal merit to those who are denying the reality of climate change who area few marginal individuals largely affiliated with special interests versus the, you know, thousands of scientists around the world. U.S. National Academy of Sciences founded by Abraham Lincoln back in the 19th century, all the national academies of all of the major industrial nations around the world have all gone on record as stating clearly that humans are warming the planet and changing the climate through our continued burning of fossil fuels.

Here are the two tactics at play here:

1. He is attempting to marginalize skeptics so that debating their criticisms is not necessary.  He argues that skeptics are not people of goodwill; or that they say what they say because they are paid by nefarious interests to do so; or that they are vastly outnumbered by real scientists ("real" being defined as those who agree with Dr. Mann).  This is an oddly self-defeating argument, though the media never calls folks like Mann on it.  If skeptics' arguments are indeed so threadbare, then one would imagine that throwing as much sunlight on them as possible would reveal their bankruptcy to everyone, but instead most alarmists are begging the media, as in this quote, to bury and hide skeptics' arguments.  I LOVE to debate people when I know I am right, and have pre-debate trepidation only when I know my position to be weak.
2. There is an enormous bait and switch going on in the last sentence.  Note the proposition is stated as "humans are warming the planet and changing the climate through our continued burning of fossil fuels."  I, and many other skeptics, don't doubt the first part and would quibble with the second only because so much poor science occurs in attributing specific instances of climate change to human action.  What most skeptics disagree with is an entirely different proposition, that humans are warming the planet to catastrophic levels that justify immensely expensive and coercive government actions to correct.  Skeptics generally accept a degree or so of warming from each doubling of CO2 concentrations but reject the separate theory that the climate is dominated by positive feedback effects that multiple this warming 3x or more.   Mann would never be caught dead in public trying to debate this second theory of positive feedback, despite the fact that most of the warming in IPCC forecasts is from this second theory, because it is FAR from settled.  Again, the media is either uninterested or intellectually unable to call him on this.

A lot of folks have asked me if I am going to comment on this

One of the fathers of Germany’s modern green movement, Professor Dr. Fritz Vahrenholt, a social democrat and green activist, decided to author a climate science skeptical book together with geologist/paleontologist Dr. Sebastian Lüning. Vahrenholt’s skepticism started when he was asked to review an IPCC report on renewable energy. He found hundreds of errors. When he pointed them out, IPCC officials simply brushed them aside. Stunned, he asked himself, “Is this the way they approached the climate assessment reports?”

I have not seen the book nor the Der Spiegel feature, but I can say that, contrary to the various memes running around, many science-based skeptics became such by exactly this process -- looking at the so-called settled science and realizing a lot of it was really garbage.  Not because we were paid off in oil money or mesmerized by Rush Limbaugh, but because the actual detail behind many of the IPCC conclusions is really a joke.

For tomorrow, I am working on an article I have been trying to write literally for years.  One of the confusing parts of the climate debate is that there are really portions of the science that are pretty solid.  When skeptics point to other parts of the science that is not well-done, defenders tend to run back to the solid parts and point to those.  That is why Michael Mann frequently answers his critics by saying that skeptics are dumb because they don't accept greenhouse gas theory, but most skeptics do indeed accept greenhouse gas theory, what they don't accept is the separate theory that the climate is dominated by positive feedbacks that amplify small warming from CO2 into a catastrophe.

This is an enormous source of confusion in the debate, facilitated by a scientifically illiterate press and alarmists who explicitly attempt to make this bate and switch so they can avoid arguing the tough points.  Even the author linked above is confused on this

Skeptic readers should not think that the book will fortify their existing skepticism of CO2 causing warming. The authors agree it does. but have major qualms about the assumed positive CO2-related feed-backs and believe the sun plays a far greater role in the whole scheme of things.

This is in fact exactly the same position that most skeptics, at least the science-based non-talkshow-host ones have.  Look for my Forbes piece tomorrow.

It is December, 2005.  The Gulf Coast had just been pounded, in succession, by Katrina, Rita, and Wilma.  Everyone was talking about how global warming seemed to be intensifying hurricanes.  In a speech just after Katrina, Al Gore said

 When the corpses of American citizens are floating in toxic floodwaters five days after a hurricane strikes, it is time not only to respond directly to the victims of the catastrophe but to hold the processes of our nation accountable, and the leaders of our nation accountable, for the failures that have taken place....

There are scientific warnings now of another onrushing catastrophe. We were warned of an imminent attack by Al Qaeda; we didn't respond. We were warned the levees would break in New Orleans; we didn't respond. Now, the scientific community is warning us that the average hurricane will continue to get stronger because of global warming. A scientist at MIT has published a study well before this tragedy showing that since the 1970s, hurricanes in both the Atlantic and the Pacific have increased in duration, and in intensity, by about 50 percent....

Two thousand scientists, in 100 countries, engaged in the most elaborate, well-organized scientific collaboration in the history of humankind, have produced long-since a consensus that we will face a string of terrible catastrophes unless we act to prepare ourselves and deal with the underlying causes of global warming....

At about the same time, the IPCC was in the process of preparing its fourth report, later released in 2007.  It said, in part:

Several peer-reviewed studies show a clear global trend toward increased intensity of the strongest hurricanes over the past two or three decades. The strongest trends are in the North Atlantic Ocean and the Indian Ocean. According to the 2007 Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC-AR4), it is “more likely than not” (better than even odds) that there is a human contribution to the observed trend of hurricane intensification since the 1970s. In the future, “it is likely [better than 2 to 1 odds] that future tropical cyclones (typhoons and hurricanes) will become more intense, with larger peak wind speeds and more heavy precipitation associated with ongoing increases of tropical [sea surface temperatures].”

So what happened?  Since Wilma in 2005, we have gone 6 full years without a category 3+ hurricane making landfall in the US, the longest span since 1900 without such an event.  And the clock is still counting.  When alarmists of all stripes were breathlessly predicting hurricane after hurricane in late 2005, the reality is that we wouldn't see another in the US for  over six years.

Of course, US landfall is in fact a terrible indicator of hurricane activity.  Its relevant to us, but it is a pretty random metric.  I said this when there were a lot of landfalls and I say it again since there have been so few.

A better metric is accumulated cyclonic energy, a sort of time integral of all large cyclonic storms worldwide.  Here is the most recent ACE figures:

As it turns out, the total strength of hurricane and hurricane-like storms has been falling almost since the exact day of Al Gore's speech in 2005 (another Gore effect!)  In fact, of late, it has hit numbers close to all-time lows.

Of course this chart will go back up some day, and then back down, and then up ... because hurricane activity has always been cyclical over decadal time scales.

The media loves to trumpet end-of-the-world predictions from folks like Al Gore and Paul Ehrlich, but they never go back five years later and back-check their predictions.  And despite their horrendous record for accuracy, the media eagerly publishes the next one.  Here is a proposed editorial rule for the MSM -- no breathless publication of anyone's next prediction without first revisiting the last one.

It is possible for the theory that the climate has a high sensitivity to CO2 (ie that a doubling of CO2 concentrations will lead to global temperature increases of 2.5C or higher) to be correct while still having ten years of flat to declining surface temperatures.  That is because Earth's great surface heat reservoir is the oceans, not the atmosphere, and so the extra heat from the greenhouse effect could be going into the oceans rather than into near-surface air.

However, it is NOT possible, as least as we (and by "we" I mean everyone, skeptics and alarmists alike) understand the climate, for CO2 to be holding a lot of extra heat and it not show up either in surface temperatures or ocean heat content.  The greenhouse effect does not turn off -- its effects may be masked in the chaotic weather systems, perhaps for years, but if the climate sensitivity to CO2 is really as high as the IPCC says, there has to be new heat going somewhere.

That is why a number of folks, including Roger Pielke, have argued for years that the best way to monitor whether we are truly seeing an additional forcing or heat input to the climate is to look at ocean heat content.  Understand, changes in ocean heat content would not tell us where the heat is coming from (e.g. anthropogenic CO2 vs. solar activity).  But it is pretty much impossible for us to imagine a new heat input to the Earth's surface, like greenhouse gas forcing from anthropogenic CO2, without observing its effect in ocean heat content.

I will turn over the story to Jo Nova, who has a good post on the new tools we have to measure ocean heat content since 2003.  In short, though, we have seen no rise in measured ocean heat content since we started measuring with technology dedicated to the task.  This means, if those who believe the climate has a high sensitivity to CO2 are right, something like 50,000 quintillion joules of energy have gone missing since 2003.  This is the "missing heat", and though climate scientists sometimes discuss it in private, they almost never do so in public.  Ocean heat is the dinosaur bone fossil that the creationists simply don't want to acknowledge.

Read the whole thing.  It is very simple and well-written and written.

PS- note in the chart above, the y-axis is mis-labelled a bit, it is not absolute heat content but changes in heat content from some base period.  Scientists call this the "anomaly."  This is typical of many climate charts.

here.

It's a wonder how, when over "97 percent to 98 percent" of scientific authorities accepted the Ptolomeic view of the solar system that we ever got past that.  Though I could certainly understand why in the current economy a die-hard Keynesian might be urging an appeal to authority rather than thinking for oneself.

When, by the way, did the children of the sixties not only lose, but reverse their anti-authoritarian streak?

Postscript:  I have always really hated the nose-counting approach to measuring the accuracy of a scientific hypothesis.  If we want to label something as anti-science, how about using straw polls of scientists as a substitute for fact-based arguments?

Yes indeed, the number of people in the newly made-up profession of "climate science" that are allowed by the UN control the content of the IPCC reports and whose funding is dependent on global warming being scary probably is very high.  The number of people in traditional scientific fields like physics, geology, chemistry, oceanography and meteorology who never-the-less study climate related topics that wholeheartedly are all-in for catastrophic man-made global warming theory would be very different

 Decide for yourself - see my video on global warming.  Am I anti-science?

My article this week at Forbes.com digs into some fundamental flaws of climate models

When I looked at historic temperature and CO2 levels, it was impossible for me to see how they could be in any way consistent with the high climate sensitivities that were coming out of the IPCC models.  Even if all past warming were attributed to CO2  (a heroic acertion in and of itself) the temperature increases we have seen in the past imply a climate sensitivity closer to 1 rather than 3 or 5 or even 10  (I show this analysis in more depth in this video).

My skepticism was increased when several skeptics pointed out a problem that should have been obvious.  The ten or twelve IPCC climate models all had very different climate sensitivities — how, if they have different climate sensitivities, do they all nearly exactly model past temperatures?  If each embodies a correct model of the climate, and each has a different climate sensitivity, only one (at most) should replicate observed data.  But they all do.  It is like someone saying she has ten clocks all showing a different time but asserting that all are correct (or worse, as the IPCC does, claiming that the average must be the right time).

The answer to this paradox came in a 2007 study by climate modeler Jeffrey Kiehl.  To understand his findings, we need to understand a bit of background on aerosols.  Aerosols are man-made pollutants, mainly combustion products, that are thought to have the effect of cooling the Earth’s climate.

What Kiehl demonstrated was that these aerosols are likely the answer to my old question about how models with high sensitivities are able to accurately model historic temperatures.  When simulating history, scientists add aerosols to their high-sensitivity models in sufficient quantities to cool them to match historic temperatures.  Then, since such aerosols are much easier to eliminate as combustion products than is CO2, they assume these aerosols go away in the future, allowing their models to produce enormous amounts of future warming.

Specifically, when he looked at the climate models used by the IPCC, Kiehl found they all used very different assumptions for aerosol cooling and, most significantly, he found that each of these varying assumptions were exactly what was required to combine with that model’s unique sensitivity assumptions to reproduce historical temperatures.  In my terminology, aerosol cooling was the plug variable.

Take all the psuedo-quasi-scientific stuff you read in the media about global warming.  Of all that mess, it turns out there is really only one scientific question that really matters on the topic of man-made global warming: Feedback.

While the climate models are complex, and the actual climate even, err, complexer, we can shortcut the reaction of global temperatures to CO2 to a single figure called climate sensitivity.  How many degrees of warming should the world expect for each doubling of CO2 concentrations  (the relationship is logarithmic, so that is why sensitivity is based on doublings, rather than absolute increases -- an increase of CO2 from 280 to 290 ppm should have a higher impact on temperatures than the increase from, say, 380 to 390 ppm).

The IPCC reached a climate sensitivity to CO2 of about 3C per doubling.  More popular (at least in the media) catastrophic forecasts range from 5C on up to about any number you can imagine, way past any range one might consider reasonable.

But here is the key fact -- Most folks, including the IPCC, believe the warming sensitivity from CO2 alone (before feedbacks) is around 1C or a bit higher (arch-alarmist Michael Mann did the research the IPCC relied on for this figure).  All the rest of the sensitivity between this 1C and 3C or 5C or whatever the forecast is comes from feedbacks (e.g. hotter weather melts ice, which causes less sunlight to be reflected, which warms the world more).  Feedbacks, by the way can be negative as well, acting to reduce the warming effect.  In fact, most feedbacks in our physical world are negative, but alarmist climate scientists tend to assume very high positive feedbacks.

What this means is that 70-80% or more of the warming in catastrophic warming forecasts comes from feedback, not CO2 acting alone.   If it turns out that feedbacks are not wildly positive, or even are negative, then the climate sensitivity is 1C or less, and we likely will see little warming over the next century due to man.

This means that the only really important question in the manmade global warming debate is the sign and magnitude of feedbacks.  And how much of this have you seen in the media?  About zero?  Nearly 100% of what you see in the media is not only so much bullshit (like whether global warming is causing the cold weather this year) but it is also irrelevant.  Entirely tangential to the core question.  Its all so much magician handwaving trying to hide what is going on, or in this case not going on, with the other hand.

To this end, Dr. Roy Spencer has a nice update.  Parts are a bit dense, but the first half explains this feedback question in layman's terms.  The second half shows some attempts to quantify feedback.  His message is basically that no one knows even the sign and much less the magnitude of feedback, but the empirical data we are starting to see (which has admitted flaws) points to negative rather than positive feedback, at least in the short term.  His analysis looks at the change in radiative heat transfer in and out of the earth as measured by satellites around transient peaks in ocean temperatures (oceans are the world's temperature flywheel -- most of the Earth's surface heat content is in the oceans).

Read it all, but this is an interesting note:

In fact, NO ONE HAS YET FOUND A WAY WITH OBSERVATIONAL DATA TO TEST CLIMATE MODEL SENSITIVITY. This means we have no idea which of the climate models projections are more likely to come true.

This dirty little secret of the climate modeling community is seldom mentioned outside the community. Don’t tell anyone I told you.

This is why climate researchers talk about probable ranges of climate sensitivity. Whatever that means!…there is no statistical probability involved with one-of-a-kind events like global warming!

There is HUGE uncertainty on this issue. And I will continue to contend that this uncertainty is a DIRECT RESULT of researchers not distinguishing between cause and effect when analyzing data.

If you find this topic interesting, I recommend my video and/or powerpoint presentation to you.

I am really just amazed by these remarks by NCAR's Dr. Ken Trenberth to be given, apparently planned for the American Meteorological Society gathering this month.   The pdf is here and Anthony Watt has reprinted it on his blog.

It is hard to know where to start, but the following excerpt is an outstanding example of climate science process where 1.  Conclusions are assumed; 2.  Conclusions are deemed unequivocal by reference to authority; 3. Debate rules are proposed wherin it is impossible to refute the conclusion; 4.  All weather events that make the news are assumed to be caused or made worse by man-made warming, and thereby, in circular fashion, further prove the theory.

Now he has gone totally off the scientific reservation into astrology or the occult or something.   He is saying that there is a high probability that if CO2 levels were 120ppm lower that, for example, the floods in Pakistan would not have occurred.  This is pure conjecture, absolutely without facts, and probably bad conjecture at that.  After all, similar events of similar magnitude have occurred through all of recorded history in exactly these locations.

Some Notes

1.  For those unfamiliar with the issues, few skeptics deny that man's CO2 has no effect on warming, but believe the effect is being enormously exaggerated.  There is a bait and switch here, where the alarmist claims that "man is causing some warming" is the key conclusion, and once accepted, they can head off and start controlling the world's economy (and population, as seems to be desired by Trenberth).   But the fact that CO2 causes some greenhouse warming is a trivial conclusion.  The hard part is, in the complex climate system, how much does it cause.  There is a an argument to be made, as I have, that this warming is less than 1C over the next century.  This number actually has observational data on its side, as actual warming over the last century, given past CO2 increases, is much more consistent with my lower number than various alarmist forecasts of doom.  Again, this is discussed in much more depth here.

2.  One interesting fact is that alarmists have to deal with the lack of warming or increase in ocean heat content over the last 12 years or so.  They will argue that this is just a temporary aberration, and a much shorter time frame than they are working on.  But in effect, the core IPCC conclusions were really based on the warming over the 20 years from 1978-1998.  So while 12 years is admittedly short compared to many natural cycles in climate, and might be considered a dangerously short period to draw conclusions from, it is fairly large compared to the 20 year period that drove the IPCC conclusions.

Update: More thoughts from the Reference Frame.

News from the United Nations:

Robert Orr, UN under secretary general for planning, said the next Intergovernmental Panel on Climate Change report on global warming will be much worse than the last one.

Hmm, that kind of confirms what critics have been saying for years, that the IPCC has nothing to do with science.  Because, you see, to my knowledge the scientists of the next IPCC have not even started their work, but the UN leadership has already determined what the report will say.  Which is consistent with their process in the last go around, where the UN political guys crafted the management summary first, and then circulated it to the scientific teams with instructions to adjust their sections of the report to fit the pre-existing conclusion.

In the same article, we get more of the "accelerating" nonsense:

He said UN Secretary General Ban Ki-moon would make it clear to world leaders in Cancun "that we should not take any comfort in the climate deniers' siren call."

"The evidence shows us quite the opposite-- that we can't rest easy at all" as scientists agree that climate change "is happening in an accelerated way."

Its not even clear what the value of the first derivative is for climate change, or even if such a metric has any meaning in the complex climate system where regional trends can easily be going in opposite directions.  But anyone who can tell you that we know the second derivative, or even its sign, is totally full of crap.

Never (except perhaps with shark attack scares which come and go) have I seen such a classic case of observer bias.   Certain events occur in the tail ends of the normal distribution.  Suddenly everyone claims that these events are happening with more frequency, mainly because they get reported with more frequency. I reported on a great example of this from a supposedly scientific government report here, where researchers mistook improved measurement of certain events as a real underlying increase in the number of such events.  Another example here.

Of course, 95 percentile events can't be, by definition, happening more frequently.  The only thing that can happen is the normal distribution can have its standard deviation increase.  Similar to the second derivitive argument above, I am not a statistician, but my sense is that the odds that we could detect a standard deviation shift in the distribution of weather events using just a few years of highly imperfect data, even if such an underlying shift existed, is really  really low.

Cross-posted from Climate Skeptic

Over at my climate blog, I discuss the amazing similarity between Obama's claims for the effects of the stimulus and the IPCC's claims for the effects of CO2 on past temperatures.  Both seem to reach their results by assuming that all the other variables in a complex system (climate or the economy) can be isolated and assessed and coincidentally are exactly the value necessary to prove that the variable under study (CO2 or the stimulus) had exactly the effect the studies authors thought it would.

A kid and his dad manage to do the analysis that NASA, the EPA, the CRU, and the IPCC can't be convinced to perform.  Awesome.

I am sort of the anti-conspiracy theorist.  I have written a number of times that events people sometimes explain as orchestrated conspiracies often can be explained just as well by assuming that people with similar preferences and similar information and similar incentives will respond to these incentives in similar ways.

I think the great herd-think around climate alarmism is a good example, and the Bishop Hill blog brings us a specific illustration from the comment section of Watts Up With That.  A commenter observed that it was pretty hard to believe that thousands of scientists could be participating in a conspiracy.  Another commenter wrote back:

Actually not so hard.

Personal anecdote:
Last spring when I was shopping around for a new source of funding, after having my funding slashed to zero 15 days after going public with a finding about natural climate variations, I kept running into funding application instructions of the following variety:

Successful candidates will:
1) Demonstrate AGW [ed:  Anthropogenic Global Warming]
2) Demonstrate the catastrophic consequences of AGW.
3) Explore policy implications stemming from 1 & 2.

Follow the money "” perhaps a conspiracy is unnecessary where a carrot will suffice.

If only alarmist results are funded, then it should not be surprising that only alarmist studies are produced.

By the way, it is probably incorrect to think of climate science really being driven by 2500 scientists.  Here is an analogy:  Strategy at General Motors is in some sense driven by thousands of workers - salesmen who know the market, channel managers who know their distribution partners, planners who watch econometric trends, manufacturers who know what can and can't be done with costs, engineers who see what the next technological opportunities, etc. -- you get the idea.

But realistically, there are probably 20-25 people who are really setting and driving and communicating the corporate strategy for GM.  And those 20-25 people will likely say to the public that their strategy is supported by all those 200,000 workers.  But in fact there are thousands, maybe even a majority, that would say that they don't support the strategy and don't think that strategy is consistent with their bit of knowlege.

I think climate science works roughly the same way.  The same 20-25 people are lead authors on the IPCC, write key reports, contribute to Al Gore's movie, get quoted in the NY Times, run the Realclimate web site, and, of course, feature prominently in the CRU emails.  And while these 25 may claim thousands of scientists support their conclusions based on the mere fact that these other scientists contributed to an IPCC report that had these conclusions, many of these scientists, when actually asked, will disagree.

Here is one thing that is never mentioned -- most of the scientists outside of climate science who have gone on the record somewhere as supporting catastrophic man-made global warming theory, if you really talked to them, would say they made their statement in support of science, not global warming theory.  Most of these folks really haven't dug into the details, but the problem was presented to them as one of science vs. anti-science.  They are told by their peers and the media that AGW skeptics are all fundamentalist super right-wing anti-science evolution deniers who think the Earth is 4000 years old.

By saying they support AGW, these scientists are really trying to make the statement that they support science.  The bitter irony is that they are doing the opposite, enabling those in the core of the climate community who are trying to duck criticism and replication by demanding unquestioning respect for their authority.  The fact is that nearly every time one of these outsider scientists - a physicist or a geologist or a statistician, say - digs into the science, they are appalled at what they find and how bad the science behind catastrophic AGW theory really is.

The new Typepad editor is not at all ready for prime time.  I cannot find a single new feature in it, but it is rife with bugs.  Ones I have found so far:

• Certain images will not upload correctly into a post.  The Typepad folks do not know why
• Twice I had a crazy error when all of the text and buttons in the "add link" popup window suddenly were inserted into the post
• All my category setup was overwritten and I had to redo it all
• The spell checker is awful.  There is no "skip all" button.  I used "IPCC" 50+ times in one post at my other blog, and had to hit skip 50 times over and over
• The eliminated the blockquote editor option.  Good job on a blog editor!
• It is slow, slow, slow.

This is one of those enforced beta situations where all of use users are forced to do the beta testing they should have done.  This is the one downside to web-based applications, because there is no way I can do a rollback to the old version.

Update:  Also, publish is way slowed down.  Sometimes it take several minutes to be able to see new posts on my blog. This one still has not appeared after hitting shift-refresh now for 3 minutes.

Update #2:  They sent me an article to trumpet all the new features, but I could find not a single new feature listed.  And it is probably a bad sign they felt the need to put this up front in the article:

If you are seeing the new compose, please be aware that it is not a beta version, it's an upgraded editor that you should be seeing.

LOL

Update #3:  Getting good comments about WordPress.  I may have to check it out.

Happy Birthday Vladimer Lenin Earth Day.  I have a few thoughts for the day:

Sucking the Oxygen Out of the Environmental Movement

Observe today how little of the discussion is about anything other than climate.  There are still many environmental issues in the world that can be improved by the application of man's effort and technology -- unfortunately, climate is the least of these but the issue getting the most attention.  Consider how the global warming panic has sucked the oxygen out of the environmental movement.  Ten years from now, I predict that true environmentalists will be looking back on the hysteria over trace amounts of CO2 in the atmosphere as a huge setback for real environmental progress.

Environmentalism and Socialism

If you attend any Earth Day events today, notice how many of the speeches and presentations and such are anti-corporate, anti-trade, anti-capitalist, anti-wealth screeds, and have little to do with the environment.  If you actually go to a live Earth Day event, you will see why the selection of Lenin's birthday was no accident.  You will not see this on the network news, because the media is sympathetic to the environmental movement and tends to edit the socialist rants out as PR protection for the environmentalists, knowing that American audiences would lose sympathy for them if they listened to the whole package. (This is mostly an American phenomenon - I have found from my brief travels in Europe that the media there does less such editing, perhaps because they know their audience is more comfortable with socialism).

The Climate Denier Trick

There are a lot of reasons not to be worried about "inaction" on global warming.  To justify the enormously expensive cuts in CO2 productions, on the order of 80% as supported by Obama and Clinton, one has to believe every element of a five-step logic chain:

1. Mankind is increasing CO2 concentrations in the atmosphere
2. Increased atmospheric CO2 causes the world to warm (by some amount, large or small)
3. The increases in CO2 from man will cause substantial warming, large enough to be detectable above natural climate variations
4. The increases in world temperatures due to man's CO2 will have catastrophic impacts on civilization
5. These catastrophic impacts and their costs are larger than the enormous costs, in terms of poverty and lost wealth, from reducing CO2 with current technologies.

Climate alarmists have adopted a rhetorical trick that no one in the media seems willing to call them on.   They like to wage the debate over global warming policy on points one and two only, skipping over the rest.  Why?  Because the science behind numbers one and two are pretty strong.  Yes, there are a few folks who will battle them on these points, but even very strong skeptics like myself accept points one and two as proved. 

Here are some examples of how this trick works.  If, like me, you do not accept steps 3-4-5 in the above logic chain, you will be called a "denier."  When asked what a denier means, a climate alarmist will often position this denial as somehow disputing #1 and #2.  On the other hand, if one publicly accepts #1 and #2, the alarmist will shout "QED" and then proceed to say that strong action on CO2 is now justified.  When an alarmist says that the a consensus exists, he is probably correct on points 1 and 2.  But he is absolutely incorrect that a consensus exists on 3-4-5.

Don't believe me?  Think back to the early Republican debate, where the moderator asked for a show of hands whether [I can't remember the exact question] man was causing global warming.  The implication is that you either have to accept this whole logic chain or not.  One can see why Fred Thompson begged to have 90 seconds to explain his position, and why the moderator, presumably in the alarmist camp, denied it to him. 

Over the last year or two, skeptics have gotten a lot better at making their argument.  Most all of them, like I do, begin their arguments by laying out a logic chain like this and explaining why one can believe that man-made greenhouse gases cause warming without accepting the need for drastic climate action.  The result?  Alarmists have stopped debating, and/or have declared that the debate is "over."  Remember that last great Al Gore climate debate?  Neither do I.

The Single Best Reason Not To Be Worried About Climate

I could, and have, in my books and videos, made arguments on many points in 3-4-5 (links at the bottom of the post).  In four, no one ever considers the good effects of warming (e.g. on growing seasons and crop yields) and most every other problem is greatly exaggerated, from hurricane formation to sea level rises.  And in five, every time someone has tried to put a price on even small reductions in CO2, the numbers are so enormous that they are quickly suppressed by a environmentalist-sympathetic media.  Suffice it to say that even the climate-sanctimonious Europeans have not been willing to pay the price for even slowing down their CO2 growth (which has risen faster than in the US), much less reducing it.

But in this logic chain, there is little need to argue about four and five if #3 is wrong.  And it is.

The effects of CO2 acting alone on temperatures are quite small -- And everyone, even the alarmists, agree!  A doubling of CO2 concentrations, without other effects that we will discuss
in a moment, will heat the earth no more than about 1 degree Celsius (though several studies recently have argued the number is much less).  This is not some skeptic's hallucination -- this is
straight out of the IPCC third and fourth assessments [IPCC text quoted here].  In fact, the IPCC in their reports has steadily reduced their estimate of the direct contribution of CO2 on temperatures.  CO2, acting
alone, warms the Earth only slowly, and at this rate we would see less
than a degree of warming over the next century, more of a nuisance than
a catastrophe.

But some scientists do come up with catastrophic warming
forecasts.  They do so by assuming that our Earth's climate is
dominated by positive feedbacks that multiply the initial warming from
CO2 by a factor of three, four, five or more.  This is a key point -- the
catastrophe does not come from the science of greenhouse gases, but
from separate hypotheses that the earth's climate is dominated by
positive feedback. This is why saying that greenhouse gas
theory is "settled" is irrelevant to the argument about catastrophic
forecasts.  Because these positive feedbacks are NOT settled science.

In fact, the IPCC admits it does not even know the sign of
the most important effect (water vapor), much less its magnitude.  They
assume that the net effect is positive, and in fact strongly so - on the order of 60-80% feedback or more, nearly unprecedented numbers for a long-term stable physical system [more on feedback and its math here].  This is particularly ironic because alarmist Michael Mann, with his hockey stick, famously posited that temperatures over the last 1000 years were incredibly flat and stable until man started burning fossil fuels, a proposition that is hard to believe if the climate is dominated by strong positive feedback.   Note that when people like Al Gore say things like "tipping point," they are in effect hypothesizing that feedback is greater than 100%, meaning that climate can be a runaway process, like nuclear fission.

In fact, with the 100 or so years of measurements we have for temperature and CO2, empirical evidence does not support these high positive feedbacks.
Even if we assign all the 20th century warming to CO2, which is
unlikely, our current warming rates imply close to zero feedback.  If
there are other causes for measured 20th century warming other than
CO2, thereby reducing the warming we blame on CO2, then the last
century's experience implies negative rather than positive feedback in
the system.  As a result, it should not be surprising that high
feedback-driven forecasts from the 1990 IPCC reports have proven to be
way too high vs. actual experience (something the IPCC has since
admitted).

However, climate scientists are unwilling to back down from the thin
branch they have crawled out on.  Rather than reduce their feedback
assumptions to non-catastrophic levels, they currently hypothesize a
second man-made cooling effect that is masking all this feedback-driven
warming.  They claim now that man-made sulfate aerosols and black
carbon are cooling the earth, and when some day these pollutants are
reduced, we will see huge catch-up warming.  If anything, this cooling
effect is even less understood than feedback.  What we do know is that,
unlike CO2, the effects of these aerosols are short-lived and therefore
localized, making it unlikely they are providing sufficient masking to
make catastrophic forecasts viable.  I go into several reality checks
in my videos, but here is a quick one:  Nearly all the man-made cooling
aerosols are in the northern hemisphere, meaning that most all the
cooling effect should be there -- but the northern hemisphere has
actually exhibited most of the world's warming over the past 30 years,
while the south has hardly warmed at all.

In sum, to believe catastrophic warming forecasts, one has to believe both of the following:

1. The climate is dominated by strong positive feedback, despite
   our experience with other stable systems that says this is unlikely and
   despite our measurements over the last 100 years that have seen no such
   feedback levels.
2. Substantial warming, of 1C or more, is being masked by aerosols,
   despite the fact that aerosols really only have strong presence over
   5-10% of the globe and despite the fact that the cooler part of the
   world has been the one without the aerosols.

Here's what this means:  Man will cause, at most, about a degree of
warming over the next century.  Most of this warming will be
concentrated in raising minimum temperatures at night rather than
maximum daytime temperatures  (this is why, despite some measured
average warming, the US has not seen an increase of late in maximum
temperature records set).  There are many reasons to believe that man's
actual effect will be less than 1 degree, and that whatever effect we
do have will be lost in the natural cyclical variations the climate
experiences, but we are only just now starting to understand.

To keep this relatively short, I have left out all the numbers and
such.  To see the graphs and numbers and sources, check out my new climate video, or my longer original video, or download my book for free.

Update: Very relevant article by Roy Spencer on the over-estimation of feedback in climate models.

Many of us, especially those who were trained as meteorologists,
have long questioned the climate research community's reliance on
computerized climate models for global warming projections.  In
contrast to our perception that the real climate system is constantly
readjusting to internal fluctuations in ways that stabilize the system,
climate models built upon measured climate behavior invariably suggest
a climate system that is quite sensitive - sometimes catastrophically
sensitive "” to perturbations such as those from anthropogenic
greenhouse gas emissions.  Unfortunately, it has been difficult to
articulate our "˜hand-waving' concerns in ways that the modelers would
appreciate, i.e., through equations.   

After years of pondering this issue, and after working on our two
latest papers on feedbacks (Spencer et al., 2007; Spencer and Braswell,
2008, hereafter SB08), I believe that I can now explain the main reason
for this dichotomy.   Taking the example of clouds in the climate
system, the issue can be introduced in the form of a question:

To what extent are climatic variations in
clouds caused by temperature change (feedback), versus temperature
change being the result of cloud variations? 

Cross-posted from Climate Skeptic.  I believe this to be an extremely important issue.  Catastrophic global warming forecasts are driven not by greenhouse gas theory, but by the theory that the Earth's climate is dominated by positive feedback.  This post discusses these issues:

It is silly to argue whether CO2 in the atmosphere can cause global warming: It clearly does.  The issue is not "if" but "how much".  The warming from man's CO2 might be 8 degrees in a century, as Al Gore might argue, in which case man's CO2 would be incredibly disruptive.  Or it might cause just a few tenths of a degree of warming, which might be unnoticeable within the noise of natural climate variation.

Interestingly, the key to understanding this issue of the amount of warming does not actually lie in greenhouse gas theory.  Most scientists, skeptics and alarmists alike, peg the warming directly from CO2 at between 0.3 and 1.0 degrees Celsius for a doubling in CO2 levels  (this notion of how much temperatures would increase for a doubling of CO2 levels is called climate sensitivity).  If this greenhouse gas warming was the only phenomenon at work, we would expect man-made warming over the next century even using the most dire assumptions to be less than 1C, or about the same amount we have seen (non-catastrophically) over the last century.  Warming forecasts of this magnitude would not in any way, shape, or form justify the draconian economic impacts of many current government carbon reduction proposals.

The key, as I have written before (and here), lies not in greenhouse gas theory itself but in the theory that the earth's climate is dominated by positive feedback.  This theory hypothesizes that small changes in temperature from greenhouse gas increases would be multiplied 3,4,5 times or more by positive feedback effects, from changes in atmospheric water vapor to changing surface albedo.

Let me emphasize again:  The catastrophe results not from greenhouse gas theory, but from the theory of extreme climactic positive feedback.  In a large sense, all the debate in the media is about the wrong thing!  When was the last time you saw the words "positive feedback" in a media article about climate?

Christopher Monckton has an absolutely dead-on post at Roger Pielke's blog about this feedback theory that I want to excerpt in depth.

This chart is a good place to start.  It shows the changes in the IPCC's estimate for climate sensitivity to CO2 and how it has changed over the course of the reports.  More importantly, he splits the forecast between the amount due directly to Co2, and the amount due to the multiplicative effect of positive feedback.  The green bar is the direct contribution of Co2, and the pink is the feedback.

We can observe a couple of things.  First, the IPCC's estimate of the amount of warming due to CO2 directly via the greenhouse gas effect has actually been going down over time.  (Note that there are those, like Richard Lindzen, who suggest these numbers are still three times too high given that we have not observed a difference in surface and lower troposphere warming that greenhouse gas theory seems to predict).

Second, you will see that the IPCC's overall forecasts of climate sensitivity have been going up only because their estimates of positive feedback effects have gone way up.  The IPCC assumes that feedback effects multiply warming from CO2 by three.  And note that the IPCC's forecasts of feedback effects trail those of folks like James Hansen and Al Gore. 

So how confident are we in these feedback effects?  Well, it turns out we are not even sure of the sign!  As Monckton writes:

The feedback factor f accounts for at least two-thirds of all radiative forcing in IPCC (2007); yet it is not expressly quantified, and no "Level Of Scientific Understanding" is assigned either to f or to the two variables b and κ upon which it is dependent....

Indeed, in IPCC (2007) the stated values for the feedbacks that account for more than two-thirds of humankind's imagined effect on global temperatures are taken from a single paper. The value of the coefficient z in the CO₂ forcing equation likewise depends on only one paper. The implicit value of the crucial parameter κ depends upon only two papers, one of which had been written by a lead author of the chapter in question, and neither of which provides any theoretical or empirical justification for the IPCC's chosen value. The notion that the IPCC has drawn on thousands of published, peer-reviewed papers to support its central estimates for the variables from which climate sensitivity is calculated is not supported by the evidence.

Given the importance of feedback to their forecasts, the treatment in the latest IPCC report of feedback borders on the criminal.  I have read the relevant sections and it is nearly impossible to find any kind of discussion of these issues.  A cynical mind might describe the thousands of pages of the IPCC report as the magician grabbing your attention with his left hand to hide what is in his right hand.  And what is being hidden is that ... there is nothing there!  Feedback is the pivotal point on which the whole discussion of drastic carbon abatement should turn and there is nothing there. 

Monckton goes further, to point out that hidden in the IPCC numbers lies an absurdity:

if the upper estimates of each of the climate-relevant feedbacks listed in IPCC (2007) are summed, an instability arises. The maxima are -

Water vapor 1.98, lapse rate -0.58, surface albedo 0.34, cloud albedo 1.07, CO₂ 0.57, total 3.38 W m^-2 K^-1.

The equation f = (1 - bκ)^-1 becomes unstable as b → κ^-1 = 3.2 W m^-2 K^-1. Yet, if each of the individual feedbacks imagined by the IPCC is increased to less than the IPCC's maximum, an instability or "runaway greenhouse effect" is reached.

Yet it is reliably inferred from palaeoclimatological data that no "runaway greenhouse effect" has occurred in the half billion years since the Cambrian era, when atmospheric CO₂ concentration peaked at almost 20 times today's value

Positive feedback can be weird and unstable.  If there is enough of it, processes tend to run away (e.g. nuclear fission), which is what Monckton is arguing that some of the IPCC assumptions lead to.  Even when feedback is less positive, it still can cause processes to fluctuate wildly.  In fact, it is fairly unusual for long-term stable processes like climate to be dominated by positive feedback.  Most scientists, when then meet a new process, would probably assume negative feedback until proven otherwise.  This is a particular issue in climate, where folks like Michael Mann have gone out of their way to argue that the world temperature history over the last 1000 years before man began burning fossil fuels is incredibly stable and unchanging.  If so, how can this be consistent with strong positive feedback?

Anyway, there is a lot more numerical detail in Monckton's post if you want to dig into the equations.

I would add one thing to his analysis:  If you look at the last 100 years of history, the change in temperature given the observed change in CO2 levels comes no where close to a climate sensitivity of 3 or more, even when you assign all historical warming to CO2 rather than other effects like the sun.  In fact, as I showed in this analysis, climate sensitivity appears to be 1.2 when one assigns all past warming to CO2, and something well less than that if one accepts the sun and other effects also play a role.  These historical analyses would point to feedback that is either zero or negative rather than positive, more in line with what one would expect from complex natural systems.

You can see a discussion of many of these topics in the video below:

Via Climate Skeptic:

The catastrophe that Al Gore and others prophesy as a result of greenhouse
gases is actually not, even by their admission, a direct result of greenhouse
gas emissions.  Even the IPCC believes that warming directly resulting from
manmade CO2 emissions is on the order of 1 degree C for a doubling of CO2 levels
in the atmosphere (and many think it to be less). 

The catastrophe comes, not from a mere 1 degree of warming, but from the
multiplication for this warming 3,4,5 times or more by hypothesized positive
feedback effects in the climate.   Greenhouse gas theory gives us warming
numbers we might not even be able to find amidst the natural variations of our
climate;  it is the theory of strong positive climate feedback that gives us the
apocalypse.

So, In a large sense, the proposition that we face environmental armageddon
due to CO2 rests not on greenhouse gas theory, which is pretty well understood,
but on the theory that our climate system is dominated by strong positive
feedbacks.  This theory of positive feedback is almost never discussed publicly,
in part because it is far shakier and less understood than greenhouse gas
theory.  In fact, it is very probable that we have the sign, much less the magnitude,
of major feedback effects wrong.  But if we are considering legislation to gut
our economies in order to avoid a hypothesized climate catastrophe, we should be
spending a lot more time putting scrutiny on this theory of positive feedback,
rather than just greenhouse gas theory.

My son finished his science fair project to measure the Phoenix urban heat island, the effect the IPCC swears is too small to have an effect on surface temperature measurements.  See all his results at Climate Skeptic.

Over at Climate Skeptic, I discuss a Cato study that finally gets at an issue I have tried to press for years:  That even if one accepts the worst of the IPCC warming scenarios (which I do not) the
cost of CO2 abatement, particularly in terms of lost economic growth, is far
higher than the cost of rising temperatures -- ESPECIALLY for the poor. 

Hurricanes are a great example.  The world is probably warming a bit due to man's CO2, but likely less than the catastrophic rates one sees in the press.  This warming may or may not increase hurricane severity.  But let's assume it does.  Let's say Asia faces an extra cyclone or two each year from global warming. 

Over time, trends in deaths from hurricanes and severe deaths have shown no correlation with storm frequency or severity.  Death rates from storms track nearly perfectly with wealth:  As wealth has increased in the US, severe storm deaths have dropped to nearly zero;  Where countries are less wealthy, they experience more death.  Bangladesh is not the site of some of the deadliest storms on record because they get hit by the worst storms, but because they are poor.  (figure source)

As a result, if we really face this tradeoff (which I doubt) the world still is better off richer with 10 hurricanes than poorer with 8.