Basics of Greenhouse Spectra

I am not an expert on climate science but every now and then I run into something that most people don’t understand and try to add to public understanding. A common question is the interaction between different greenhouse gases. Why does water (H₂O) vapour, present in much higher concentrations, not dominate any changes in the greenhouse effect? Why is methane (CH₄) said to be a much more effective greenhouse gas than carbon dioxide (CO₂) molecule for molecule?

There are two major issues I address here: water vapour is not present in equal measure throughout the atmosphere, and greenhouse gases vary in the wavelengths of infrared they absorb preferentially, and hence complement each other to some extent, rather than competing for the same photons.

Water vapour is present in the atmosphere at highly variable concentrations, up to 4% at sea level (40,000 parts per million by volume, ppmv), compared with CH₄, currently at about 1.8ppmv, as compared with CO₂ at 387 ppmv (methane and CO₂ numbers from NOAA Earth System Research Laboratory). Water vapour content of the atmosphere varies considerably because the capacity of the atmosphere for holding water vapour is temperature-limited. The average over the whole atmosphere is 0.4% (4,000 ppmv), but over 99% of this is in the lower atmosphere (troposphere).

Some of the answer to the CO₂ vs. H₂O issue is that CO₂ is a well-mixed gas, meaning its concentration is not temperature-dependent and given time turbulence will mix any addition equally into the atmosphere, so CO₂ additions contribute to the greenhouse effect throughout the atmosphere. H₂O additions on the other hand are limited both by the fact that the addition can precipitate out rapidly and H₂O is limited in the volume of atmosphere it can populate. But that is not the whole picture.

Look at these three pictures, lifted from Principles of Planetary Climate by Raymond T. Pierrehumbert, from which I also derive the following explanation:

The most important thing to observe in these pictures is that the peaks are in different places. This is important because the peaks represent parts of the spectrum in which each of the three greenhouse gases prefer to absorb. We cannot do an accurate calculation of the difference between each gas based on these pictures, because each data point is averaged over 50cm^-1 and therefore represents a range (hence graphing five curves for each, representing the minimum, 25th percentile, median, 75th percentile and maximum absorption coefficients for the interval graphed at each point). Nonetheless, it’s clear that at the peak near 600cm^-1, CO₂ is a much stronger absorber than H₂O. Wavenumbers in “cm^-1” are common in spectroscopy, and are simply 1/wavelength in cm.

You may be wondering why methane has no peak significantly higher than the other gases if it’s so much stronger a greenhouse gas. The reason lies in the sharp drop in effectiveness of absorbing as all molecules capable of absorbing a photon near a peak in the graph have absorbed a photon, meaning any more such photons can pass straight through. Because of methane’s relatively low concentration, it is still absorbing near a peak. If all else were equal, methane would actually absorb less per increase in concentration than CO₂ because its peak is not as close to the peak of outgoing infrared (which is close for a planet of the Earth’s average temperature to the 600cm^-1 peak in the  CO₂ curve). Notice how the scale on the vertical axis is logarithmic. The approximately straight edges of the decline from the peaks in all the graphs are the reason that increases in greenhouse gas concentrations have a logarithmic relationship to temperature increase.

There’s a lot more to it than that. The graphs I illustrate here are for 10% of the Earth’s atmospheric pressure, because they are the only ones I could find on comparable axes. However, full atmospheric pressure does not change the shape of the curves in a big way. Also, if you remember your high school physics, you may wonder why we have relatively continuous graphs, since quantum physics says a molecule can only occupy specific energy states, implying that the graph should be disjoint data points. When a photon encounters a molecule at the same time as that molecule exchanges potential energy with another molecule, the difference in energy between the photon and an allowed state of the molecule can be made up (or reduced) by an exchange of kinetic energy. This is called collision or pressure broadening.

The overall factors that go into determining the greenhouse effect and in general the overall climate of a planet are very complex; you really need to read a book like Principles of Planetary Climate. But be warned: it’s heavy going if you aren’t comfortable with calculus.

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Further Reading

If a text book is too much for you, here are some lecture notes on The Climate System from Columbia University. The syllabus link provides pointers to content.

The Day it Rained Forever

I'm working on a new novel with the working title, The Day it Rained Forever. Here in Queensland, it is starting to feel a bit like that.

While the floods here are not causing the devastation the recent Pakistan floods caused, because the population is lower and we have good early warning systems, you nonetheless have to start wondering why one in hundred year events are happening so often.

While it’s wrong to label one event as evidence of climate change because climate is a long-term average of weather, one of the predictions of climate theory is that as the energy in the system increases (what is happening now), the hydrological cycle intensifies. That means bigger swings between drought and deluge, and more intense droughts and floods.

If you look at the history of flooding where I live in Brisbane, it looks as if things have actually improved since the big flood of 1893:

However, we need to take into account the completion of the Wivenhoe Dam in 1984, which has had a significant effect in mitigating flooding. We should have had a major flood in 1999, as you can see from the fact that Wivenhoe peaked at about 135%; the sudden drop-off arises from the excess being let out. The way a flood mitigation dam works is 100% is the normal water storage capacity and anything over 100% is the excess that would have gone into a flood. As soon as the possibility of flooding reduces, this excess has to be released. In a tidal river like the Brisbane, water can be released to coincide with low tide. Obviously there is a limit to this: if the dam approaches its true 100% (possibly 200%), there is no option but to release water even if the timing is not ideal.

Here is the overall history of the dam as far back as the official SEQ Water web site goes:

Note the peak in 1999, when the dam first performed its flood mitigation duties. The current peak doesn’t look too dramatic but let’s take a closer look:

Observe the spikes to the right of the curve, all over the 100% line. These are all occasions when the sluices were opened. Let’s see exactly how many spikes there have been to date:

Four so far, and no end to the rains in sight. Contrast that with only one occasion in the past when the dam sluices had to be opened since it was constructed. The latest peak is nearly 150%, much higher than the 1999 peak of 135%, illustrating that you need to look at the numbers rather than eyeball a graph.

Going back to 1893, the pattern then was a series of floods, with one big one that dominated the rest. We won’t see that pattern again in Brisbane because of the role of Wivenhoe, but without the dam, the current flood would be at least as bad as that of 1974, possibly at the 1893 level. Clearly, these “once in a century” events are happening more often than that.

None of this of course is evidence of climate change. It is however a warning. The level of climate change we have seen so far has added about 0.8°C to the pre-industrial global average. James Hansen, in Storms of My Grandchildren, predicts things become hairy with more than another 1°C of warming. He bases this number mainly on the threat of rapid disintegration of ice sheets. However, we should not expect that level of warming to occur without further intensification of the hydrological cycle. Flooding on this scale should happen more often. Exactly how much more often, and how much the variation between wet and dry will intensify, are open questions. Do we do the experiment? People with water above their roofs or even lapping at their floorboards may well say no. I certainly do.

Update: 10:30 am, 11 January 2011

I’ve just heard on ABC local radio, Wivenhoe is at 173% of capacity, despite all the major releases. Further releases that won’t cause flooding are no longer an option.

Update: 8:40 am, 16 January 2011

Since my last update, Wivenhoe was heading to 200%. The dam spills over the top of the wall at 225%, and is not designed to withstand that kind of spillage, so the gates had to be opened to the extent of flooding significant parts of the city. The peak level was 191% on the night of Tuesday 11 January 2011 (though this does not show up on the official dam web site because of the time of day at which the measurement is taken).

Now the flood waters have receded, the flood level was a bit below that of 1974, despite twice the rainfall in Wivenhoe’s catchment, so the dam has had some useful effect. I don’t know how the rainfall over the city itself differed, but that carried on for a long time if not very intensively. At very least that would have contributed to the flood by saturating the ground.

My own home was above the flood level, but homes only a few blocks away were inundated, despite being quite far from the river. Despite being several metres above flood level, the ground was so saturated that a little water seeped up through cracks in my garage floor (the garage is cut into the ground). This is a trivial problem compared with what others have endured, but illustrates how saturated the ground was when the Wivenhoe gates were opened fully.

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To help

• If you would like to contribute financially to helping out with flood victims, I recommend doing so via the state government web site.
• If you are in Brisbane and want to help, the best thing to do is to walk to your nearest flood site (with waterproof boots, strong gloves and any equipment you can carry).
• The city council is bussing volunteers around, but their strategy of mustering volunteers at sites far from the rail network means you may be stuck in traffic for a long time getting in, going to your work site, and getting home again. If you aren’t in a location where you can help, look into the council volunteer scheme.
• Volunteering Qld is also helping out but are currently overwhelmed with offers, so feel free to register with them to help out in the longer term but don’t expect to be used immediately.

The Australian’s Resolve Cracks

The Australian last weekend published a lengthy defence of its position on climate change, claiming its editorial policy was never anti-science, with the following rather surprising wording emphasised:

THIS newspaper supports global action on climate change based on the science.

They published a letter from me, cutting much of the substance, so I present it in full here:

I read Graham Lloyd’s lengthy defence of this paper’s coverage of climate science (“Climate debate no place for hotheads” 4/12) with interest.

The Australian may have said all these things but in a context where denialists writing junk were not only given equal time with real scientists, but lauded as in the case of Ian Plimer, who was given an incredible free ride for his book which was torn to shreds once it was in the hands of scientists, rather than the hard right ideologues in your editorial offices. I am also reminded of the embarrassingly incorrect article, "Sorry to ruin the fun, but an ice age cometh" (23/04/2008) by Phil Chapman, who claimed that a decline in the number of observed sunspots presaged an ice age. Current indications are that 2010 is likely to set a new record for overall annual temperature. So much for that.

This paper has a long history of promoting cranks and contrarians with no standing in the scientific community. If these people were correct of course it would be great that you were giving them space, but they have proved time and time again to be talking rubbish. So how do you consider it acceptable that you are giving them equal time? The argument that a contrarian position is owed equal time no matter how bereft it is of logic or factual support was invented by the tobacco industry in 1954 and is as valid today as it was then. If your editorial staff does not understand the difference between pro-industry propaganda and genuine scientific debate, you cannot claim to be a quality paper. Allowing cranks to present easily debunked pseudo-science ad nauseam is not a freedom of speech issue, it is a quality of journalism issue. In any case you are extremely selective on where this kind of bogus balance applies: you do not for example insist on allowing Trotskyites equal time on the business pages, no doubt on the basis that their theories haven’t worked in practice. Well, guess what. Neither have contrarian theories of climate.

If it is indeed this paper’s position that we should base our actions on the science, how about reporting the science without insisting on bogus balance of at least equal space for anti-science? How about some articles informing the public on exactly how uncertainty is deal with in science, rather than stoking the completely false claim that uncertainty in climate science renders the whole field invalid? There’s a lot you can do to defend your reputation without threatening litigation, and I suggest you start by understanding why many scientists hold you in contempt. A mirror can be a most useful tool.

I strongly recommend to anyone wanting to understand the nature of the propaganda war on science that started with tobacco, took on the ozone hole and is now attacking climate science to read the book Merchants of Doubt by Naomi Oreskes and Erik Conway. Oreskes is an accomplished science historian and her careful scholarship adds to the understanding of this topic I’ve built from my own experience in taking on other bogus anti-science battles in the past, including tobacco and AIDS denial, as well as reading other books like George Monbiot’s Heat.

More interesting to me though is why the paper has suddenly decided to defend its track record, questionable though its defence is: the paper’s environment editor, Graham Lloyd, argues that the paper’s own editorials have consistently argued for a science-based approach, while ignoring the fact that allowing so much space for cranks undermines public understanding of the science. But why are they doing this? Do they care about their reputation after all?

Let’s consider one example, the common attack line of the anti-science warrior since the days of tobacco: undermine public confidence in scientific findings by harping on uncertainty, as if this is a sole property of this one area of applied science, and nothing can be done until all uncertainties are resolved. To anyone who does science of the real world, this is a patently absurd line of attack, but it is one that bought the tobacco industry decades, held up action on the ozone hole and caused hundreds of thousands of unnecessary HIV deaths in South Africa. No real-world science is devoid of uncertainty; the biggest irony in this line of attack is that industries like oil that pay for anti-science activism deal with enormous uncertainties in their own line of work. It is beggars the imagination that the industry’s own scientists do not know how to manage uncertainty.

One editorial doesn’t do it for me: the paper will have to build a consistent track record of reporting well-founded scientific positions, and refusing to publish polemics disguised as science. Oh yes, and Graham Lloyd: Bjørn Lomborg isn’t an economist. His background is in political science.

Big IPCC Error

Here’s an IPCC error we don’t hear reported too often. This picture from the 2009 Copenhagen Diagnosis illustrates how far out the IPCC’s 2007 Fourth Assessment Report was in predicting reduction in Arctic sea ice extent. The black line is a combined (ensemble) figure of a range of simulations, and the dashed lines represent the highest and lowest values of the simulations. The red line is the measured sea ice extent.

Since 2007, when sea ice extent reached an all-time minimum (in recorded history), many climate deniers have made a big thing of how sea ice extent has “recovered”. Since this graph was made, sea ice extent has fluctuated a bit, without hitting the 2007 low again, but still well below simulations reported by the IPCC.

The other thing climate deniers have done is attack the IPCC wildly whenever a trivial error has been spotted. Guys, this is a big one. I’m waiting for you all to get excited.

The clean energy imperative

I’m increasingly convinced that the reason for so much opposition to climate change science is not because of some flaw in the science but because there’s fear of the collapse of industrial society if we stop using fossil fuels. This is not an irrational fear but it leads to irrational behaviour like attacking scientists personally, and pay good money to attend vaudeville shows where deniers reassure audiences with rubbish.

The best response is to study clean energy alternatives.

I recently gave a talk at a Transition Towns meeting in Kenmore, Qld. I’ve published a PDF of the slides at scribd, and will add commentary here as time permits. Meanwhile the Kenmore TT people have posted a TED talk on how to roll out the electric car. Interesting.

The warmest year?

Since the whole brouhaha over stolen climate scientists’ emails broke last year, a clear emphasis of the science obfuscation lobby has been trying to con the public into believing the data is all flawed, and there’s nothing to worry about. One of the fall-backs in the attack on the mainstream has been the claim that satellite data hasn’t been showing as strong an increase as the data sets based on surface measurements. While NASA does their measurement independently from the UK Hadley Climactic Research Centre (CRU), the conspiracy-theoretic view is that they are all in it together.

Well, how is the satellite record looking lately? I moseyed over to the AMSU-A temperatures site maintained by Roy Spencer of the University of Alabama at Huntsville (a favourite of the denialosphere for his consistently lower warming trend) and Danny Braswell of NASA and did the following, which you can repeat to update the results:

1. click Draw graph
   
2. click all the checkboxes and click Redraw
   

This is my result:

 The orange line that stops in April is the daily temperatures for this year. Observe that since 10 January, every day has had the highest temperature for that date in the satellite record going back to 1998. This particular data only starts partway through 1998 so we don’t have the complete picture back to the last record or near-record year (depending whose data you look at; some put 2005 slightly higher than 1998) but if this trend continues, 2010 will easily set a new record for satellite temperatures. Is this because we’re in a super-monster El Niño? Not if you look at the SOI (most recent values at time of writing from the Australian Bureau of Meteorology):

The thing to note here is that a negative SOI value puts us in El Niño (higher than average temperatures) while a positive value indicates La Niña (lower than average temperatures). Also, there is a lag of about a year between SOI peaks and global temperature peaks. The El Niño in 2004-2005 with a peak early in 2005 resulted in 2005 being an unusually warm year. Do we see a similar pattern for the last 12 months? No. Although we have been in an El Niño phase since the second half of 2009, that effect has been nowhere near strong enough to account for a new record in temperatures, certainly not as early as January 2010.

Could the SOI be amplified by a rising solar cycle? Sunspot numbers are trending up but we are still pretty close to the solar minimum:

If you’d prefer to look at total solar irradiance (TSI) as measured by satellites, rather than sunspots, go to PMOD, where you’ll see the energy inputs from the sun are not on a steep upwards trend and should be significantly lower than in 2004-2005:

You have to line this data up with SOI to get a good idea of what is causing short term blips in global temperatures: El Niño does not in general coincide with the peak of the solar cycle. At some point this will happen, resulting a really hot year. But leave this aside, since it won’t happen soon. What we have now, early 2010, is a temperature trend tracking above all recorded temperatures since 1998 (or more properly 1999, since we don’t have 1998 temperatures in the first half of the year in the AMSU-A data set) and we can’t pin that effect on El Niño or on the sun.

What next? Is someone already planning to steal Spencer’s emails?

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Update

I’ve plotted the mean daily temperature anomaly versus 2005 (each day minus the same day in 2005) for the year to 25 April. The trend (linear regression) over this period is 6°C per century – making up for lost time from previous slower warming by satellite measurements? Oh, and the correlation coefficient of 0.79 is highly significant even with this small sample size. Enjoy (or not, if you don’t want warming to be real). For missing data (a small fraction of the total), I took the average of the two nearest days that did have data.

And here's the AMSU-A big picture for 25 April 2010:

and an update on the SOI picture:

SOI is not the whole picture for predicting the effect of ENSO on temperature; a more comprehensive model clearly shows 2010 should be a cooling phase, not a warming phase.

Still lots of time in the year …

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Yet Another Update

If you go to the site now, it says Channel 4 failed in 2008. That’s what happens in science: a weird result is more likely to be a consequence of instrument failure than anything else. The major data sets do show 2010 as one of the warmer years though not by a significant margin (despite the other data indicating it should have been a cool year, including the solar cycle starting to exit an unusually deep low and a strong La Niña).

What I find particularly odd about all this is this note (dates in US format, so this is in March)

03/06/2008/1200UTC:NOAA-16 AMSU-A channel 4 has gone bad.  As a result, NOAA-16 ATOVS sounding files are no longer being produced by NESDIS, thus they are no longer in the "atovs" dumps in the GDAS and CDAS networks and they (temperature retrievals) are no longer available for assimilation by the CDAS.  The "atovs" dumps now contain only NOAA-15 ATOVS soundings and only these temperature retrievals (cloudy only) are assimilated by the CDAS.  In addition, the failed channel 4 data has resulted in no NOAA-16 AMSU-A data being assimilated by the NAM/NDAS or GFS/GDAS GSI (even though these files are still being produced by NESDIS and NOAA-16 AMSU-A data continue to be dumped in the "1bamua" files in the CDAS, GDAS, GFS, NDAS and NAM networks).

It seems someone knew nearly 2 years before the weird 2010 data went live that there was something wrong with the data. Curiously, we didn’t see wild accusations flung around the blogosphere about this one. I leave it to the reader to explain.

Fool me twice

As the cacophony of voices attacking climate science grows, I have to wonder: where are the journalists? Have they forgotten their job description? In any other field, if such an obvious, misinformed lobby arose, would they rate any attention?

Well, maybe.

During organized tobacco’s war on science, many newspapers reported propaganda created by paid tobacco lobbyists as a legitimate alternative to mainstream science. Other industries took up the same strategy: producers of CFCs who paid ozone hole deniers, and asbestos vendors who refused to acknowledge guilt in killing their own workers in the most horrific way in the cause of making a quick buck. In South Africa, according to a Harvard study, over 300,000 people died unnecessarily because the Mbeki government chose to believe pseudo-science when reality did not suit the president’s politics.

Fit to the Pattern

In all these cases, the tactics were remarkably similar. A small group, mostly with no scientific credentials in the area, supported by an even smaller group with some relevant scientific background, claimed that they represented an alternative viewpoint that had to be aired, and increasingly stridently portrayed the mainstream as dishonest, excluding alternative theories and even a religion. In each case, if you scratched below the surface, the strident accusations had no merit.

Is climate science any different? Not in principle, but in degree. The number of actual paid lobbyists is quite small, and the tactics have been narrow (as ably documented by John Mashey): discredit a small number of key scientists, tarring the rest as in on the plot, and cause general doubt among the public who are unaccustomed to evaluating scientific evidence. From there, rely on the gullibility of journalists and a ready constituency of conspiracy theorists and absolutist free marketeers who abhor any form of government intervention, and then rely on the viral properties of the Internet to spread the message far and wide. All this is a clever refinement on previous business-sponsored anti-science campaigns that didn’t have the Internet as a tool to spread disinformation on the cheap (AIDS denial was the first anti-science campaign I know of that did this, and it went pretty far without the benefit of an industrial sponsor). The biggest difference though is that mishandling climate change has the potential to cause disaster on an unprecedented scale. The ozone hole has made it inconvenient to live in countries like Australia, where sun-lovers court cancer if they don’t apply enough sun screen. Asbestos kills in horrible ways, but the number of victims is limited to those who are directly exposed. Tobacco too kills in horrible ways, if in much larger numbers than asbestos. AIDS is a terrible affliction to treat as a political problem that can be wished away. But climate change is a threat that carries risks for the entire biosphere. Not only that, if we wait too long before switching to an alternative energy economy, the economic effects of a sudden worldwide shift to new forms of energy could be devastating.

The Risks

Clearly, the lowest-risk approach to climate change is gradual emissions reduction, and a slow transition to a new energy economy, a process that has enough benefits to be worth exploring long before we were sure of the science. Had we started this in the late 1980s when the evidence started to become clear, we would be well on the way today towards a clean energy economy. So why the massive resistance? As with CFCs, tobacco, asbestos and HIV, there are political and economic constituencies who are threatened by change.

The big risk to humanity is not just from the dangers in failing to slow climate change and to re-gear economies for low emissions. It is also from discrediting science. Science is not a matter of opinion: a theory stands or falls by how well it fits the evidence, including how well its predictions stand up to measurement. By attempting to turn climate science, and indeed any science that offends a particular special interest, into a matter for debate where the evidence counts for less than personal preference, we risk reverting from a society of reason to a society of superstition. So there are big issues at stake, and the fact that so much of the discourse on this subject has swung away from reason to personal attack, and insisting that the facts bend to opinion rather than that the science be evaluated for what it is, is cause for serious concern.

The Real Failure

Why have they been allowed to get away with it? George Monbiot, in his book Heat, exposed the link between the anti-science of tobacco and climate change (more links in my discussion of his book). It does not take brilliant investigative journalism, following on from that, to realise that the attack on climate science is a massive con designed to buy the fossil fuel industry time, at the expense of the rest of humanity, who stand to pay a huge price if action is taken too late.

This is not the first time this tactic has been used, yet the anti-science movement gets away with it again and again. Tobacco. HIV. Asbestos. CFCs. And now climate science. Fool me once, shame on you. Fool me twice, shame on me. Fool me five times, I’m a journalist.

Call to Action

So what can you do? Join my campaign or any other that you feel comfortable supporting to oppose demonizing science. Write letters to the media, making it clear you do not support turning science into a matter of opinion. Sign my pro-science petition, and consider joining my LinkedIn pro-science group to share ideas.

Replies to questions about climate science

One Terry today at The Australian asked some questions. Unfortunately the paper is a lousy forum to conduct a conversation because it updates slowly and is patchy in posting comments. Also, Terry, the answers to your questions are readily available. It’s not my fault if Australia’s only national daily doesn’t report science much above the level of superstition and rumour. I would offer my humblest grovelling apologies if it were my fault. For that, you must go to Mr Murdoch.

Tom Clark, Philip Machanick, Sancho, et al

Why not settle the discussion and show us sceptics the proof for the following:
1. That current anthropogenic CO2 emissions are the major cause of global warming. Bear in mind that the physics shows that the amount of warming from CO2 decreases as the concentration increases. Thus there has to be a huge forcing, what is it?
2. That the minimal warming from anthropogenic CO2 causes climate change. Please detail which elements of the climate (storms, drought, heat, floods, tornadoes, etc.) are changing, and the proof that the major cause is anthropogenic CO2.
3. The earth has been warmer in its recent past (Roman and Medieval periods), and these warm periods were very beneficial to mankind. Thus if (and it’s a big if) anthropogenic CO2 has any real influence on the global temperature, why should we be concerned about living in temperatures that existed, to the benefit of mankind, in the past 2000 years?

When you answer, bear in mind that computer predictions are not science.
Also the recent (30 years) global temperature readings are badly compromised, not least from the fact that the original 6000 measuring sites have been reduced to 1500, and it wasn’t the warmest locations that were removed.

Just this once, I’ll do your homework for you. But listen up: you can find all this stuff yourself. The trick is to use Google Scholar, rather than regular Google, which turns up masses of dross. Unfortunately a good fraction of the research literature is paywalled, but NASA makes all theirs public so I will use them disproportionately so you can check my sources. I include a few paywalled papers where the important detail is in the free to view abstract.

1. Scientists have known since the 19th century that the relationship between CO₂ concentration and warming is logarithmic. Please don’t parade this fact as evidence of the ignorance of scientists, but rather as evidence of your ignorance of the mainstream. Forcing per doubling of CO₂ is 4W/m² [Hansen et al. 2005]. To put this into context, a 2% increase in solar irradiance adds about 4W/m² [Hansen et al. 2008]. A 24 W/m² increase in solar irradiance only over summer, accompanied by a 4-day increase in the duration of summer, caused by a change in axial tilt [Huybers 2006], is enough to tip the earth out of an ice age, so 4W/m² is a big change – especially as it’s not limited to one season and a limited part of the planet. The maximum variance in solar irradiance since satellite records began is 0.36%, less if you smooth the data to take into account that the biggest variations are very short-term (graph below from TSI Composite Database plot of data 1978-1999). There is no known theory of climate that can use solar variability and other natural influences to reproduce temperature variation since the 1950s. We can only reproduce the trend by models that include natural influences and anthropogenic warming.

2. No serious climate scientist is claiming that the current level of warming is resulting in major increases in storms etc. Yet. There are however measurable effects like loss of Greenland and Antarctic ice mass [Velicogna 2009 – see figures from this paper below] – and many others like glacier retreat, change in species range, and accelerated rates of extinction. You can find plenty of evidence for these if you look. If you want catastrophic effects before you accept firm evidence of climate change, you’re crazy. Predictable effects such as shrinking glaciers are enough for me, especially as many of these metrics are happening faster than predicted.

Antarctic Ice Loss (blue data points: unfiltered)	Greenland Ice Loss (blue data points: unfiltered)

3. The evidence of warming in the Medieval Warm Period is patchy and unreliable, and recent evidence suggests the warming was not as fast as that at present [Loso et al. 2007]. A conspiracy-theoretic site styling itself “CO2 science” has an extensive archive of papers purporting to support a globally warmer period in medieval times. I examined the papers they claimed had the highest-quality evidence, and found the temperature peaks varied by as much as 600 years in different locations around the world. That is not a globally warm period. I haven’t seen the evidence that Europe was warmer in Roman times than it is now; there certainly is unlikely to be solid evidence of warming on a worldwide scale for the simple reason that the resolution of our methods of measuring temperature is poor that far back in time. In any case, “warmer” is a relative term. Our current temperatures are on the back of greenhouse warming that hasn’t concluded. Even if we do not add more CO₂ to the atmosphere, we have another 0.5°C of warming or so due from slower feedbacks. The Roman world and Medieval Europe may have benefited from local warming from a sub-optimal climate for agriculture to a better climate for agriculture. Warming today is unlikely to have that effect: much of the world’s rice crop for example is grown at close to its temperature limits for high yields, a concern for food production in China [Tao et al. 2006].

On your other comments, if computer predictions aren’t science, we are going to have to stop doing biology and most other branches of modern science. Computer models are no different than mathematical models, except they can process a lot of information fast. Like mathematical models, they can be wrong. This is why scientists check on each other, and build their own models from scratch, rather than rely on a popular model to be correct.

The claim that measurements are compromised by reduction in climate stations is rubbish, especially the claim that the removed sites were from cooler areas. Temperature measurements are not in absolute readings, but anomalies, deviations from a baseline. The baseline for each weather station is based on typical measurements for that type of station. The number used from each station in the overall temperature calculation is not its temperature but its difference from the baseline. This method was introduced for several reasons, one of which is to avoid exactly the sort of problem to which you allude. NASA documents their approach in detail and provides all the computer programs and data. Check it yourself.

 I have a question for you now:

If climate science really is junk, why is it necessary to oppose it with vaudeville acts, personal attacks, stealing email and clear and obvious lies?

And if you agree with me is that science is about supporting theories with evidence, not personal attack and harassing scientists with whom you disagree, sign my petition.

References

[Hansen et al. 2005] Hansen, J., Mki. Sato, R. Ruedy, L. Nazarenko, A. Lacis, G.A. Schmidt, G. Russell, I. Aleinov, M. Bauer, SS. Bauer, N. Bell, B. Cairns, V. Canuto, M. Chandler, Y. Cheng, A. Del Genio, G. Faluvegi, E. Fleming, A. Friend, T. Hall, C. Jackman, M. Kelley, N. Kiang, D. Koch, J. Lean, J. Lerner, K. Lo, S. Menon, R. Miller, P. Minnis, T. Novakov, V. Oinas, Ja. Perlwitz, Ju. Perlwitz, D. Rind, A. Romanou, D. Shindell, P. Stone, S. Sun, N. Tausnev, D. Thresher, B. Wielicki, T. Wong, M. Yao, and S. Zhang 2005. Efficacy of climate forcings. J. Geophys. Res. 110, D18104, doi:10.1029/2005JD005776
[Hansen et al. 2008] Hansen, J., Mki. Sato, P. Kharecha, D. Beerling, R. Berner, V. Masson-Delmotte, M. Pagani, M. Raymo, D.L. Royer, and J.C. Zachos, 2008: Target atmospheric CO₂: Where should humanity aim? Open Atmos. Sci. J., 2, 217-231, doi:10.2174/1874282300802010217
[Huybers 2006] Peter Huybers. Early Pleistocene Glacial Cycles and the Integrated Summer Insolation Forcing, Science 313 (5786), 508, 28 July. [DOI: 10.1126/science.1125249]
 [Loso et al. 2007] MG Loso, RS Anderson, SP Anderson, PJ Reimer, P J. Sediments Exposed by Drainage of a Collapsing Glacier-Dammed Lake Show That Contemporary Summer Temperatures and Glacier Retreat Exceed the Medieval Warm Period in Southern Alaska, Eos Trans. AGU, 88(52), Fall Meet. Suppl., Abstract PP44A-01
[Tao et al. 2006] Fulu Tao, Masayuki Yokozawa, Yinlong Xu, Yousay Hayashi, Zhao Zhang, Climate changes and trends in phenology and yields of field crops in China, 1981-2000, Agricultural and Forest Meteorology, Volume 138, Issues 1-4, 29 August, Pages 82-92, ISSN 0168-1923, DOI: 10.1016/j.agrformet.2006.03.014
[Velicogna 2009] I Velicogna. Increasing rates of ice mass loss from the Greenland and Antarctic ice sheets revealed by GRACE, Geophys. Res. Lett., 36, L19503, doi:10.1029/2009GL040222

Time to Defend Science

I have set up a petition so those who object to the traducing of climate science can make their voices heard. I hope even opponents of the mainstream position will sign, because the issue is not whether the science is correct or not, but whether science should be tested by weighing evidence against theories, or by personal attack on scientists.

Even The Guardian, a paper that usually breaks from the herd and attempts to report matters like this accurately, has jumped on the bandwagon of attacking climate scientists personally. In this article, reprinted in the internationally distributed Guardian Weekly with the title Research red in tooth and claw journalist Fred Pearce makes numerous errors. I was particularly annoyed at this reprinting of the article, since the weekly paper has more time to review content for errors. Here is what I've written to the editor:

Fred Pearce's long article "Research red in tooth and claw" is riddled with errors and misinterpretations. First, he identifies a paper by Lars Kamel as the one referred to in stolen CRU emails because "It is the only one published on that topic in the journal that year" then goes on to explain how the paper was never published. Either it was published, or it wasn't. Second, he goes on at great length about how CRU's temperature analysis has not been recreated by anyone else, and cannot be because of lack of access to the data. While I have problems with the whole concept of lack of access to data, this is denialist spin. NASA's Goddard Institute for Space Studies has independently constructed a temperature record using mostly the same data sources, and all of its data is public, and there are other independent temperature records against which CRU's can be tested. Pearce's understanding of peer review is also confused. There is nothing improper in asking other academics for inputs into reviewing a paper, and this happens very widely. Nowhere does Pearce present evidence that confidences were breached.

As Pearce could easily have discovered had he done the job he's evidently being paid to do, despite Jones's threat to keep junk papers out of the IPCC, they are in fact cited as references. The "MM" paper referred to is unlikely to be the McKitrich and Michaels paper on urban heat islands because this was published in 2007, 3 years after email Pearce quotes. The paper concerned is more likely to be that by McIntyre and McKitrick of 2003 (also rubbish), which is in fact cited in IPCC reports.

In one of Pearce's most serious blunders, he fails to report the fact that half of the editorial board of Climate Research including the newly-appointed editor in chief resigned over the journal's lapse in standards at the hands of De Freitas.

Pearce says the fact that Jones was new to the IPCC process was no excuse for errors of judgement. How new is Pearce to journalism?

PS: has Rupert Murdoch bought The Guardian?

There is a deep problem here when a usually trusted news source starts behaving in this way. Science is traditionally conducted through the research literature for a good reason. Unqualified people can easily make mistakes when assessing a complex field. The hard thing is translating research into policy. Human society does not on the whole do that very well, and I am not proposing alternatives here. What I do however object to in the strongest terms is traducing science as a whole and vicious often ill-informed personal attacks on scientists.

If you agree, sign the petition.

Of Drama Queens and Climate Science

Yet another bunch of anti-science letters in The Australia, this time in response to an article reporting the UK's chief scientist as saying climate scientists are prone to dramatise claims.


It suits the tabloid press (including those who disguise this tendency with a broadsheet layout) to frame issues in absolutes and set up crazy debates. Anything any scientist says that sounds the vaguest bit extreme or contrary to known science gets blown out of proportion, and the 99.9% of scientific work that doesn't fit this model is ignored.

Try reading the scientific literature using Google Scholar instead of regular Google as your search engine. You'll be amazed to find the vast majority of accusations against climate scientists (here for example the claim that they underplay uncertainties) are totally unfounded. Try however to get an article into a newspaper that tells it the way it is rather than setting it up as a screaming match between drama queens and you will get nowhere.

I stopped buying newspapers that do this and only read them where I can find them for free (online, in coffee shops etc.). If more people did this they would get the message.

It's hard to get a real debate going in the online comments so I will repeat some of my points here.

Peter: your claim that the raw data is "destroyed and manipulated" is rubbish. Most of the raw data is freely available. The drama queen argument here is that if a tiny fraction of the data used by one research group isn't available then all of it isn't. NASA for example makes ALL their climate data and their computer code available (see here for theirs among others). Enough data has been available for years for any serious scientist wanting to undo the mainstream theory to do so. Instead, we get vicious personal attacks, theft of email and political arguments.

SW1: your claim that further flaws will come to light is not only plausible but almost certain, but so what? Published science is riddled with errors. A researcher develops a new theoretically superior instrument, and in the rush to get published, makes mistakes in calibration. A research group finds a new angle on a problem and in their enthusiasm at finding something exciting, miss an obvious error. Peer review is a filter but not a perfect one, and this kind of thing can slip through. Sometimes the reviewers are lazy, or have a predisposition to accept the paper's findings. That's why scientists check on each other. Let's take as an example the 2009 paper by Lindzen and Choi that purported to show a much lower climate sensitivity to CO₂ increases than the accepted range of 1.5-4.5°C. This paper was trumpeted over the blogosphere as yet another nail in the coffin of anthropogenic global warming. Now various analyses of their paper are showing that their approach was flawed, including one by Roy Spencer, who generally disagrees with the mainstream figure on climate sensitivity. There is at least one published response that shows the paper to contain serious errors. The drama queen version of events: Lindzen once again strikes a fatal blow against science, and the "corrections" can safely be ignored.

Another example is the claim that the oceans are cooling. NASA has an interesting story on their web site of how the science in that case unfolded. One of their researchers, Josh Willis, published results using a new technology, Argo floats, that showed the oceans were cooling. While he described this as a "speed bump" rather than a slowdown in warming, the blogosphere went gaga and many people still quote this result. What actually happened was some of the floats were under-reporting temperature, while the older technology used for older measurements was over-reporting temperature, and these two effects combined to create an appearance of cooling. Any cooling would contradict a range of other kinds of evidence, so had these results held up, it would have been a major challenge to the science. Instead, the problem turned out to be in the data. Again, nothing too unusual. But the drama queen interpretation is Willis overthrew the entire theory, and the conspirators worked hard in the background to reinstate it.

My focus here has been on attacks on the mainstream but of course there are people out there who make extreme claims about the risks of climate change. These people do not represent the scientific community, who as a whole are pretty loath to make extreme claims without strong evidence. But these stories too get the headlines.

The bottom line? Google Scholar is your friend. Whenever something implausibly extreme or contrary to accepted knowledge appears, go to the scientific literature. Preferably after waiting 6 months for the dust to settle.

Climate of Fraud Part 2

Here’s a pair of letters that appeared in The Australian. First, one from me:

MARC Hendrickx (Letters, 17-18/10) alleges that Pen Hadow “had to be rescued in the Arctic in 2003 due to the extreme cold and excessive ice”. Hadow in fact had always planned to be airlifted off once he arrived at the Pole, and the only issue was that he started his solo walk from Canada to the North Pole late in the season, when a pick up was risky because the ice was breaking up.

If it’s impossible to support an argument without resorting to fabrication or ad hominem attack, you don’t have a case. Every global warming denial theory falls apart when examined against the evidence, so the denial cult has given up arguing the facts.

Here’s one they won’t like. Despite the fact that we are in the deepest solar minimum—the period of least solar activity in the solar cycle of the sun—in almost a century, temperatures remain close to record highs. Had the “it’s all the sun” crew been right, we should have seen temperatures close to 100-year lows over the past few years.

As for the actual state of the Arctic, Hadow is not the only authority who has Arctic summer sea ice disappearing in the next 20 to 30 years. Several papers and reports have backed this conclusion. I’ve been working in science for nearly 30 years, and I have yet to encounter a situation where wishful thinking overturns a theory, especially when that wishful thinking runs counter to well-established physics (as is the theory of greenhouse gas warming).

If there are genuine climate-change sceptics who have alternative theories that explain the facts better than the mainstream theory, let’s hear them by all means. That’s how science works. But if the accepted theory is right, we are running out of time fast. The alternative theories have all failed any reasonable scientific test, while the mainstream has held up pretty well against the most concerted political attack on any scientific theory since the Inquisition stopped burning scientists at the stake. It’s time to move on and start addressing the real problems.

Philip Machanick

Then, a day later, a response:

USING dubious observations to bolster a preferred hypothesis is not how science works. Philip Machanick (Letters, 20/10) is on thin ice when he suggests that the human-caused global warming scenario is the only plausible explanation for our recent climate history. There is a plethora of contradictory data.

Reconstructions of the solar intensity record for recent centuries, referred to by Machanick, are speculative. Prior to 1978 there were no direct observations from outside the atmosphere and estimates of changing intensity have been made from proxies, such as sun spot numbers. As reported by the Intergovernmental Panel on Climate Change, even the successive satellites have calibration uncertainty. It is therefore a matter of dispute as to whether or not we are in the deepest solar minimum in almost a century, as Machanick claims.

If melting of Arctic sea ice is to be taken as the canary in the coal mine for human-caused global warming, then there are relevant reputable data extending over hundreds of thousands of years from which to draw comfort. Oxygen isotope ratios from Greenland ice cores and pollen analysis from sea-bed sediment cores off southern Greenland independently show a consistent pattern.

Over the past half-million years the Arctic has oscillated through glacial cycles, each of about 100,000-year duration, and we are currently in a relatively warm interglacial phase. During each of the previous interglacials the Arctic was warmer than at present. The pollen and isotope records also suggest that the Arctic was warmer during the current interglacial between 4000 and 8000 years ago, when the carbon dioxide concentration was much less than now, and well before industrialisation.

William Kininmonth

Kininmoth is accusing me of gross misconceptions about how science works (note the bits I’ve highlighted). Heavy. I should return my PhD, and stop working as a researcher. Or, maybe I should do what a researcher does, and re-examine the evidence – starting from the pronouncements of Kininmoth himself. My original letter did not come out of nowhere: I was attempting to demonstrate how the data the denialists use directly contradicts the evidence. Well, here’s another Kininmonthian contribution from December 2008:

THE attempt by Professor Marvin Geller to discredit scientists who do not follow the climate alarmist agenda only highlights the inconsistencies of his case ("Professor sheds light for climate sceptics”, 4/12).

The evidence of solar influences on climate is well documented, especially the relationships established over many centuries of observations, that link sunspot numbers and cosmic ray activity to global temperature.

The lack of a creditable explanation for the relationships should be reason for more research, not dismissal of the mechanisms.

It is wrong to claim that the past few decades of warming cannot be explained without including human influences.

The error of his statement is obvious from his own explanation for the temperature peak of 1998 as a massive El Nino event. The El Nino is a temporary reduction of upwelling in the surface layer of the tropical Pacific Ocean that decreases the entrainment of cold subsurface water; the warmer tropical waters provide additional energy to warm the planet during an El Nino event.

Research by Michael McPhaden and Dongxiao Zhang, published in the journal Nature in 2002, identified a major and sustained reduction in Pacific Ocean upwelling and warmer ocean surface temperatures that became established in 1976.

This was at the beginning of the most recent global warming episode that the alarmists mistakenly attribute to human-caused carbon dioxide.

Interactions between the ocean and atmosphere, the two fluids that regulate Earth’s climate, are now widely recognised as contributing to climate variability on a range of timescales.

William Kininmonth

Note again my highlighting.

What was that again, about “Using dubious observations to bolster a preferred hypothesis”? Is that not a vaguely similar methodological flaw to changing your degree of support for the validity of a data set when it no longer supports your “preferred hypothesis”?

I could also dispute other points he makes, but this to me is sufficient. If you want to accuse others of unscientific practice, make sure your own approach is beyond reproach.

Update

The WCC3 conference has downloads of speakers’ slides, and a voice recording. Latif’s talk (about a third of the way into the audio) is especially interesting since it has been so widely misreported. In particular, he addresses the need to get better resolution and accuracy for decadal predictions; this has somehow been interpreted as his saying that it will get cooler over the next two decades. If you want to get the best out of his talk, download Latif’s slides and follow them while listening to his part of the audio. I’ve posted a longer article elsewhere on how Latif has been misinterpreted.

Climate of Fraud

I saw Bob Carter, a leading opponent of climate science, on SBS TV (semi-commercial government-owned channel in Australia) news tonight (13 August 2009). Shortly afterwards, the view switched to a slide carrying the claim that the IPCC’s models “predict monotonic warming, and they are wrong”. Here is the slide, captured from the online edition of the news (about 1:18 in from the start):

This is a blatant lie.

I reproduce here a graph from the IPCC’s 2007 report [Randall et al. 2007]:



A “monotonic increase” means that temperatures can only increase over time, with a possibility that they may stay level at times. Examine the graph. The yellow area represents results from 58 simulations. The black line is the actual temperature record and the red line the average of the simulations. What you can observe is that the yellow lines and their average, the yellow line, do not either increase or at least fail to drop over the entire period of the simulation.

Indeed it would be bizarre if any reasonable approximation to the real climate showed a monotonic temperature increase, unless that increase was so extreme as to overwhelm all natural variation, and no serious climate scientist is making any such claim. It is widely known that the two major short-term influences on temperature are the El Niño Southern Oscillation (ENSO) and the solar cycle. This is why climatologists define the climate as the long-term average. It is a shift in the long-term average that is a concern, not whether temperatures increase every year.

Why is the Carter crew claiming that the theory demands this? Because they want to knock the theory down, and have no evidence to the contrary, so they have no option but to lie.

That he is trundling this stuff out along with cronies from the right wing US Heartland Institute at a time when there is political activity around climate change is no surprise. That they cannot do better is. Professional science obfuscators – including Heartland – confused the public for years around the link between tobacco and cancer without resorting such obvious falsehoods.

[Randall et al. 2007] Randall, D.A., R.A. Wood, S. Bony, R. Colman, T. Fichefet, J. Fyfe, V. Kattsov, A. Pitman, J. Shukla, J. Srinivasan, R.J. Stouffer, A. Sumi and K.E. Taylor, 2007: Climate Models and Their Evaluation. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M.Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge

The Australian and Postmodern Science

Saturday 18 April 2009 represented a new high or low point (depending on your perspective, which turns out to be significant) in The Australian’s project to develop a new postmodern science, in which “objective truth” depends totally on the observer, and deconstruction replaces evidence-based evaluation.

First, there was an article “Revealed: Antarctic ice growing, not shrinking”, which selectively quotes Australian Antarctic Division glaciology program head Ian Allison to create the impression that there is no warming in the Antarctic. In fact one of the major investigations in which the AAD is involved is into sea ice thickness, which they propose could be a more significant indicator of future ice loss than ice extent (the ice can thin for many years before it disappears, as happened with Arctic sea ice). The same author had another article, “Change is a cold certainty”, which despite spinning the position as the Antarctic is not warming, was reasonably balanced when you got to the detail.

Then, there were two opinion pieces about a new book, The climate of disastrous consensus, by geologist Ian Plimer. I will focus on the article that deals more directly with the content of the book, rather than the opinion piece by Christopher Pearson (there’s just so much one person with a day job can do). Here are some quotes from the article, which quotes the book directly, so I assume it is not misrepresented:

• CO₂ is not a pollutant but a necessity of life. For a start, it is food for plants. "Global warming and a high CO₂ content bring prosperity and lengthen your life ... without CO₂ there would be no complex life on Earth" – a silly statement. You can say the same about water, but not only can you drown in the stuff, but you can actually die from drinking too much water. Extra CO₂ makes plants grow faster, but not without limit, and there’s no guarantee that the plants of human interest will gain the most. What’s more, other effects of climate change like change in temperature and rainfall patterns are more significant to agriculture.
  
• While an increase in atmospheric carbon dioxide theoretically may contribute to temperature rise, Plimer says there is no evidence to show this and plenty of proof, if you choose to look for it, to the contrary – the evidence for this is very strong and is based on science that’s been known since the 19th century. To assert this in a newspaper article without providing Plimer’s evidence makes him look a fool.
  
• To reduce climate change to the single variable of carbon emissions abandons "all we know about planet Earth, the sun and the cosmos", Plimer says, and that is a leap of faith no self-respecting scientist should take – unmitigated drivel. No serious climate scientist models the entire system based on one variable. To see how absurd this claim is, you only need to do a google search on two keywords: “IPCC attribution”. I've included a graph typical of the approaches used (note the multiple influences included).
  
• When he peers back in time, there were periods when atmospheric CO₂ was much higher than it is now yet produced no disastrous shift in the climate – perhaps he’d care to point out what fraction of life on the planet dates from that era. More than 90% of species from eras when CO₂ was substantially higher than it is today are extinct. Four out of five mass extinction events are associated with rapid climate change.
  

The article goes on to an interview. Here are a few excerpts:

• He reviewed five computer predictions of climate made in 2000, underpinning IPCC findings, and found there was no relationship between predicted future temperature and actual measured temperature even during a short period – why would he expect the models and measurement to line up over a short period? To make such a supposition is to misunderstand the nature of climate science. There are very big day-to-day fluctuations in weather. Over a month, averages smooth these fluctuations out. Over a year, more so. Climate is about stepping back and looking at the long-term average. The current trend is for warming at a rate of 2°C per century, an average of 0.02°C per year. This small a change is not discernible over natural variation unless you look at a long enough stretch – which is why climate is generally looked at as an average over 30 years.
  
• There was alarm in the 1970s that the decreasing temperature was heralding another ice age, he says – this is standard propaganda from his side of politics. A 2008 paper has found that contrary to this often-repeated claim, papers published from 1965 to 1979 on climate change totalled 7 predicting cooling, 44 predicting warming and 20 that were neutral. That’s what we mean about “evidence” in the mainstream scientific community. We don’t take things as given because people we like are saying them: we check the facts.
  
• The ice caps are geologically unusual; people were growing barley and wheat in Greenland 1000 years ago. – Are we supposed to infer from that that Greenland’s ice cap is less than 1,000 years old? I can only suspect that the journalist has things garbled here. Plimer can’t be that ignorant. Ice core studies of Greenland go back over 100,000 years. It is very likely that Greenland and much of Europe was warmer 1,000 years ago, but there is no evidence that this warmth extended worldwide. If you check the temperature records of any location, there is a good chance you will find an unusually warm period. Do all such periods around the world line up at the same period? No, not over the last 1500 years, the era when the “Medieval Warm Period” and Little Ice Age occurred in Europe. Some places were warmer 1,500 years ago, others 1,000 years ago.

To accuse others of ignoring evidence creates an onus on you to examine evidence with extra care. Repeating often-debunked talking points does not qualify. Possibly The Australian has been very selective in its reading and picked out its favourite talking points. If they have misrepresented Plimer’s book, I hope to see a rebuttal from him. Failing which, I’m not going to read the book. I am from the old school of science, where the evidence is based on measurement, not on your political preconceptions.

Call me old fashioned, but I, unlike The Australian, don’t see a role for post-modernism in science. The old model of examining the evidence, developing hypotheses, testing them against new evidence until they look solid, then promoting them to theories works for me – as it has done for the creation of a robust industrial society. What a pity the same intellectual rigour does not apply to other areas of society – like running a newspaper.

Everything you know is wrong

Have you ever woken up, stretched, and before you had time to stop yourself, suddenly realised that everything you know is wrong?

Probably not.

Most people never have that happen to them, even if they really are wrong about everything.

I lived in South Africa during the apartheid years, and you’d think that no White South Africans supported the system to hear people talk now – but believe me, as an opponent of the system, I didn’t get much support. At some stage a lot of people must have changed their opinions, some without missing a beat or changing their perception of facts they had available for years.

If their views today are correct, they must have applied a very different filter to reality in the past.

This mysterious ability to interpret events in the light of a preconception, with an unshaken belief that any new facts that contradict that belief can’t be correct, has a name. It’s called confirmation bias.

Confirmation bias is the tendency to discount facts that don’t fit your preconception.

Let’s look at another example, one of my favourite examples: climate change.

I am going to look at just one aspect of this by now stale debate: the argument that it was much warmer than today during Mediaeval times. There’s an extensive bunch of web pages devoted to this cause, collecting a mass of evidence showing that talk of it being unusually warm today is some sort of conspiracy. The trouble is, they didn’t bother to line up all the dates and average the temperatures world-wide, which is what you look for if you are looking for global climate change. If it was unusually warm in one spot 1000 years ago, unusually warm somewhere else 500 years ago, unusually warm in yet another spot 1500 years ago, you don’t have a global warm period. Yes, there is evidence that parts of the world were warmer then. No one disputes that. But if you look at isolated temperature records, you can find all sorts of apparent anomalies. Layer those over a preconception, and you have a “theory” – but not one you can call science.

If you are already convinced of the case, the mass of evidence papers over the cracks pretty well. But I am a sceptic. I want to analyze any theory put to me for flaws, and a mass of evidence that’s not tied together properly does not make a case. The fact that no one has put that evidence together and yet the authors of the site in question claim they do already have a case should convince no one but those who want to be convinced irrespective of the facts.

So am I guilty of confirmation bias?

Nothing would please me more than to discover that the whole global warming thing was a hoax. We know from experience of other clashes between industry interests and campaigns for the common good that industry wins – or at least can resist for decades (tobacco, asbestos, the ozone hole).

If the mainstream opinion of climate science is correct (or even too optimistic, as some argue), we are in deep, deep trouble, because there is no way we will be able to take sufficient action in time to avoid significant ill effects. So I am really keen – despite having run for the Greens a couple of times – to find flaws in the theory. The problem is, every attempt I’ve seen to do so is heavily larded with confirmation bias. We see use of language like “alarmist” that’s designed to appeal to those already convinced: to me a sure sign of lack of confidence in the argument (why appeal to the emotions if your logic is sound?). We see harping on points that have been debunked. We see doubtful statistical methodology, attempts at interpreting data without any scientific method (naturally while claiming to be “real science” – this is the language of propagandists, not scientists), we see nitpicking insignificant points that do nothing to overturn the basics of the science.

In short, I’m waiting to be convinced. I would be really happy to wake up one day to discover that everything I know about climate change is wrong. What about the people pushing the contrary case? Are they open to being wrong? Or has it become something of a religion to them? One thing you can bet on: if we see catastrophic consequences of failure to act, the people who today are working so hard at inactivism will be very, very quiet.

Forget Climate Change: A Fossil Fuel Future’s a Fantasy

on Jenkins in his article “The warmaholics’ fantasy” (The Australian 06/01/2009) ends by asking this: “The real question is in acknowledging the end of fossil fuels within the next 200 years or so: how do we spend our research time and dollars?”

Unfortunately, Jenkins has made the common error of not factoring in growth in demand. The latest annual figures available from BP’s authoritative Statistical Review of World Energy 2008 show that energy use grew 2.4% from 2006 to 2007. If we use this number as escalation against 200 years at current usage, we actually only have 75 years of fossil fuels left. Allow a more aggressive growth rate of 5% to factor in industrialisation of currently less developed countries, and fossil fuels will be gone in 50 years.

I’ve graphed the trend with 200 years’ worth of fossil fuel as the starting point to make it easy to see how the various growth rates pan out. As you can see, constant use takes us to zero after 200 years (off the scale of the graph). As you should be able to see from the graph, when constant demand would have used less than 40% of all carbon fuels, 2.4% growth will have used them all up. 5% growth would hit zero when only about 25% of reserves would have been consumed at fixed demand.

While it’s conceivable that 200 years is an under-estimate, any excess on that amount would include fuels from increasingly inaccessible and environmentally fragile sources. In fact, even to reach that level would require exploiting resources like tar sands and oil shale that are not only environmentally problematic but also expensive to process. What’s more, coal and oil are complex mixes of chemicals that have many uses; it’s silly to burn valuable, irreplaceable chemicals.

Long before we reach an era of real shortage, markets will be subject to massive swings as speculators ride fears of shortage – as we saw recently with oil prices. As demand from developing countries increases, we can expect prices to escalate for the simple reason that supply is unlikely to keep up with demand. We’ve already mined out much of the coal that’s really easy to dig up (Britain had massive reserves in the nineteenth century), and oil is increasingly being sought in expensive locations like the deep sea and Arctic.

Even without disputing Jenkins on climate change (I can’t see how he advances the debate with ad hominem attacks – and am pleased to see he has subsequently apologised for this in a letter in The Australian), there is a clear case for exploring alternative energy now, and doing so aggressively.

It’s clear that we will need to find alternatives to fossil fuels and sooner than most think. Will this necessarily result in massive pain? Luckily, Cambridge physics professor David MacKay has already provided a good start at understanding the problem in a new book, Sustainable Energy — without the hot air (not yet published in Australia; you can download a free copy from his web site). To cut to the chase, he calculates that Britain will battle to achieve a sustainable-energy economy because it has too high a population density and not enough sun. Much of Europe likewise will have to look to sunny low-population countries like Libya to import solar electricity. Australia gets little coverage in the book since the focus is on solutions for the UK. MacKay has reduced his calculations to simple examples that can easily be reworked for other parts of the world, or different solution mixes. Comparing us with the UK and its need to import solar electricity from Libya for example illustrates that we really do not have much of a problem here. Our population density is less than Libya’s, and we have plenty of sunshine.

What of the problems often raised about intermittency of wind and solar power? There are many creative solutions out there of which MacKay provides a good sampling. He reminds us that electricity providers have to be geared to handle massive changes in demand; much of the same techniques can be used to manage changes in supply. For example, electric cars, while charging overnight, could be equipped with smart meters that draw power when it’s cheap, and put some back when it’s expensive. Heavy users whose usage is not time-dependent could be scheduled to draw power when it’s plentiful. And of course existing techniques for load management such as pumped storage (sending water uphill when electricity is plentiful; using a downhill flow later to drive a generator) can be scaled up.

There’s too much detail in the book to cover in a short article like this. I strongly recommend that anyone interested in energy alternatives read it. Since he has neatly compartmentalised his solutions, it is relatively easy if you disagree with one to pull it out and replace it by another option. I’ve seen many attempts at covering small parts of the problem. Only a comprehensive approach such as this is really any good. Not only that, MacKay has a fine sense of humour.

I propose we stop worrying about who is right and wrong in the climate change debate (see other articles on this site for some answers to Jenkins’s points), and move as fast as we can to sustainable energy. To do so requires some hard political will, not wishy-washy strategies like charging for pollution permits then giving most of the money back to the big polluters. If we get this right, we will be insulated from damaging swings in energy commodity prices. Should the worst predictions of climate change turn out to be true, we will be well on the way towards a clean energy economy. If not, we will be a bit ahead of where we need to be when fossil fuels start to run out and become really expensive. All three ways, we win.

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Also published at Online Opinion.