There is an alternative to Labor’s ETS and the Coalition’s shambolic carbon scheme which seems superior to both: a fee-and-dividend system.

It’s a simple idea: the major emitters pay a fee per tonne of CO2 emitted. This is not a “great big tax”; the revenue raised is distributed straight back into the economy, either directly as a dividend paid out per person, or indirectly via a reduction in other taxes. Given Australia’s recent emissions of around 25 tonnes per capita, and an initial fee of $20 per tonne, an annual dividend of around $500 could be paid out to each person in the country.

The idea is that this dividend does two jobs at once: it offsets price increases in carbon-intensive goods and services (like coal-based electricity), and it encourages consumers shift to low-carbon alternatives.

In economic theory, the “fee-and-dividend” approach is a little less efficient than an ETS, but in practice it would be far more effective.

A fee-and-dividend system is likely to be harder to manipulate and weaken through the lobbying efforts of Big Carbon. We’ve seen the Government’s ETS proposal watered down with free permits and handouts to the extent that the effective initial carbon price is almost zero, rendering the ETS almost entirely pointless.

Fee-and-dividend also has the advantage of a relatively stable carbon price. The fee would be steadily raised over time, but would be far more predictable than under an ETS. This is crucial in securing investment in low carbon solutions.

All in all, a fee-and-dividend approach looks like a good bet if we want to bring about a low carbon future.

(This appeared as a Letter to the Editor in The Canberra Times of Wednesday 17 Feb 2010.)

Part of another thread of letters to The Canberra Times (posted here partly just as a record, because the CT’s site is so hopeless that most letters don’t even appear online), starting with this on 2 December:

Alan Barron and John Coochey (Letters, 30 November) appear to have been taken in by the misinformation that has been circulating around climate denial blogs: that the emails recently stolen from the Climate Research Unit at the University of East Anglia represent some kind of damaging blow to mainstream climate science.

Despite innumerable claims to the contrary, the emails contain no evidence whatsoever of scientific malpractice, nor of a corruption of the peer review process, nor of some cabal of malevolent individuals trying to manipulate results. And there is nothing that represents a credible scientific argument against the consensus picture of anthropogenic global warming.

The emails paint a picture of working scientists engaged in their discipline: battling disinformation, discussing interpretations of results, and in fact demanding scientific rigour. The worst charge that can be constructed from this collection of over a thousand emails (carefully selected and presented out of context to paint as damning a picture as possible) is that some ill-advised comments were made about an FOI request. If that’s the worst that the deniers can find in a decade of emails among a large number of scientists, that speaks volumes for their integrity and professionalism.

The emails do illustrate a culture which to some extent resisted openness with scientific information, and there is room in some circles for more openness on scientific data and methods, and discussion of the full range of opinion. Suggestions that contemporary climate science is based on secret data are deeply misinformed; for instance, the data and models used in NASA’s work are fully available.

Those who deny the evidence on climate change are seemingly so lacking in credible scientific evidence for their cause, and so unwilling to accept that they could be wrong, that there is now only one option left: conspiracy theories. They seem to be operating on the principle that, if you say it loud enough and often enough, enough people will believe it.

Matt Andrews

A reply appeared on 4 December:

If Matt Andrews (Letters, December 2) removes his head for a moment from his “cone of silence” he will see and acknowledge that there are many scientists who question the science of man-made climate change.

He would also know that the University of East Anglia, home of the Climatic Research Unit (the driver of man-made climate change and the IPCC) has announced the director of the unit will relinquish his position pending an investigation into allegations that he overstated the case for man-made climate change.

The reasons for the university’s action can be found in the released emails and documents that on any reading clearly show a course of extremely questionable scientific conduct by the unit.

The results of this conduct, when “cited”, has permeated through countless other scientific papers, resulted in Copenhagen and now forms the basis of the PM’s and Labor’s policy on climate change, ie ETS.

The debate on the science of man-made climate change, on what response if any is necessary or appropriate, is not over, it is just beginning.

Bob Edwards, Kambah

I then replied with this, published on 8 December:

Bob Edwards (Letters, 4 December) illustrates just how comprehensively many have been taken for a ride by the propaganda and disinformation surrounding the release of emails stolen from the Climate Research Unit in the UK.

Much of the controversy has surrounded this sentence in one email from Phil Jones, director of the the CRU: “I’ve just completed Mike’s Nature trick of adding in the real temps to each series [...] to hide the decline”. Looks dodgy at first glance, right? But let’s look a bit deeper. This is part of a discussion of tree ring data, used to construct a long term temperature record over many centuries. There’s a well-known aspect of tree growth in high latitudes called the “divergence problem”: trees have grown more slowly than expected since around 1960, given the rising temperatures that we’ve observed. The slowdown seems to be due to air pollution and other regional factors. Consequently the tree ring data since around 1960 is of little statistical value in this context, and it is entirely correct practice that the recent portion (the “decline”) be removed (“hidden”) from the long term temperature reconstruction, since we have more reliable ways of measuring temperature in recent decades anyway.

The fact remains that there is overwhelmingly strong support among climate scientists for the basic observations that the world is warming and that human activity is primarily responsible. In fact, there is not a single credible and substantial line of evidence against those conclusions; the arguments usually promoted on denial blogs have been debunked over and over again.

Matt Andrews

Update, 9 December: this reply appeared in today’s edition:

Matt Andrews’ letter (December 8 ) refers to the “divergence problem” in tree ring data from 1960 onwards.

Trees grow faster when the climate is more favourable (ie, warmer and wetter), and form coarser rings than when they do when it is cold and dry. Usually, the finer rings are a product of winter, and the coarser rings, of summer. How can he or anybody else ignore observational data showing colder and dryer conditions at high latitudes, in order to make the data conform to the theoretical global warming concept?

This attitude of twisting or ignoring facts to suit a theory is why the leaked emails show such deplorable and unscientific treatment of the data, and make one wonder where the people who did this have any ethical sense at all. The first principle of science is that if the data don’t support your clever idea, then you think again and find an idea that fits the data – not the other way around.

Dr Marjorie Curtis, Kaleen

To which I replied:

Dr Marjorie Curtis (Letters, December 9) claims that the exclusion of high-latitude tree ring record since 1960 from long term temperature proxies constitutes a deliberate and unethical manipulation of the data to fit a theory, and that the recent narrow tree rings must indicate colder and dryer conditions in recent decades. It would serve Dr Curtis well to learn something about what the “divergence problem” really means.

We know that Arctic tree rings can reflect the temperature well, going back many centuries, as the tree ring data correlates strongly with a range of other indicators of temperature. Over the last century the tree ring record matches changes in temperature that we’ve directly measured via thermometers, ice area and many other indicators. The exception is that, since around 1960, tree rings in some Arctic regions have been unusually narrow relative to the dramatic warming that we’ve confirmed with satellites, thermometers and so on. We don’t know exactly why this divergence has happened in each region – in some cases it seems to be caused by increased air pollution. But the divergence is real, and very strongly established by the evidence. It would be statistically invalid to include this data since 1960 as part of a long term temperature reconstruction, and indeed such an error would almost certainly be criticised and corrected in peer review.

Accusing scientists of unethical behaviour seems to be par for the course for climate deniers these days. It’s a pity that these bold accusations are based on such profound scientific ignorance.

Matt Andrews

Another round of tedious correction of contrarian disinformation in The Canberra Times. In response to an earlier letter, I wrote this piece which appeared in the print edition of 7 October:

Anthony Moore (Letters, 3 October) claims that satellite and land-based thermometer data show no warming over the past decade. In terms of climate temperature trends, this is not just incorrect; it ignores much more important parts of the picture.

To over-simplify, the word “climate” means the long-term average of the weather, typically over periods of 30 years or more. Annual averages in temperature are dominated by large short-term variations including cycles like El Niño. So-called “sceptics” (who seem to demonstrate a remarkable lack of genuine scepticism) like to talk about “the last decade” because they can start with a huge spike in the annual average (the 1998 El Niño) and end at a low point (the recent La Niña). This says nothing about the underlying climate trend; for that you need to look at long term averages. Look at a graph showing the 30-year average temperature: it’s been steadily increasing – in fact, accelerating – since the 1970s.

The big picture is very clear. The planet has been in energy imbalance since the 1970s: the amount of energy leaving the Earth is less than the incoming energy from the Sun. The planet as a whole is heating up, due mainly to the increase in CO2 and methane, and the energy imbalance is growing. Almost all of this heating has been in the oceans; land and atmosphere heating has been a tiny part of the picture so far.

Matt Andrews

This then attracted a response on 9 October from one of the regular peddlers of the usual ill-informed soundbites:

Matt Andrews’ response (Letters, October 7) to Anthony Moore (Letters, October 3) beggars belief.

The graph on which alarmists have consistently made their case for warming is the Global Temperature Land-Ocean Index which shows Annual Means and 5-Year Means from 1880 to 2000. And now Matt wants to move to 30-year averages to capture the bigger picture – from 1970.

That should give him just one data point!

Then he accuses sceptics of using the 1998 El Nino spike to demonstrate cooling.

Rubbish! Serious sceptics cull that spike from their data and demonstrate cooling from 2001 to the present.

And, like Barrie Smillie some time back, Matt completely misses the point.

This is not about the planet having warmed, which it has since coming out of the Little Ice Age in the mid-19th century, but whether that warming is driven by CO2.

And a planet that has had two prolonged cooling periods (1940-60 and 2001-09 and continuing) while CO2 has been rising, would suggest that CO2 is not the cause. Matt is doing the fast strokes.

Aert Driessen, McKellar

I then responded with this:

Aert Driessen (Letters, 9 October) is having trouble with 30-year moving averages of global temperature, so let me clarify: using the highest quality index, NASA’s GISS, if we use the average of the 30 years of temperatures that ended in 1975 as a starting point, we can see that for each and every year since, the 30-year average that ends at that year is a little bit warmer.

It shows a steady inexorable increase – the long-term trend we call “global warming”. The same pattern is clear in the 30-year averages of the other main index, from Hadley Climate Centre in the UK.

Taking a step back, satellite measurements show that the amount of energy received by the Earth is greater than the amount of energy that is leaving: the planet is in energy imbalance, and thus is heating up. It’s been in that state since the 1970s, and the imbalance is growing.

Matt Andrews

Crikey, a prominent daily news email to which I subscribe, has a few climate denialists who pop their heads up from time to time in the Comments section. The most vocal is Tamas Calderwood, who produced this piece yesterday (in response to an article by Clive Hamilton about civil disobedience in the face of government inaction on climate):

Tamas Calderwood writes: Clive Hamilton’s call for civil disobedience is a disgrace. His own lazy arguments and lack of supporting data can’t persuade people that “the fate of the planet hangs in the balance” so he now dismisses democracy and demands action. Meanwhile, the global temperature in August 2009 was 0.23C above the 30-year mean so there’s still no sign of the coming apocalypse. Given that the temperature data supports the climate sceptics, would it be moral for us to take ‘direct action’ against the likes of Hamilton and Greenpeace? Would civil disobedience to stop the absurd and utterly ineffectual ETS be justified? I am as certain of my scepticism on this issue as Hamilton is of his doom mongering pessimism but we sort this stuff out at the ballot box in this country. I would have thought a “Professor of Public Ethics” would know that.

I responded with this in the 15 September edition:

Matt Andrews writes: Tamas Calderwood maintains his fine tradition of breathtakingly ignorant letters on climate change with a couple of claims (Letters, 14 September) just ripe for the puncturing. The first is “the global temperature in August 2009 was 0.23C above the 30-year mean”. Presumably Tamas is trying to paint a picture of negligible warming that doesn’t warrant strong action, but in fact this data point is embarrassingly devoid of meaning.

Let’s take a step back: “climate” is roughly defined as “the average of the weather over the long term”, where “long term” is usually defined as at least 30 years. Short term temperatures – the single month that Tamas cites, or even annual averages – are dominated by the wild ups and downs of the weather, the “noise” in the long term signal. The warming trend caused by human releases of greenhouse gases is very clear over the last thirty years or hundred years, but if you restrict your time period tightly enough, it’s swamped by the natural chaos of the weather.

Tamas neglects to mention that the data he’s quoting is the denialists’ favourite: UAH satellite figures. Satellites don’t measure surface temperature; they measure temperature across large cross-sections of the stratosphere and upper troposphere. That is then processed to generate an estimate of lower troposphere temperature. This is not the same as direct surface temperature measurements, for which there are several global average indexes of high statistical quality, the best of which are Hadley HadCRU and NASA GISS. Substantial issues have been raised in recent years over implausible anomalies in UAH data.

Tamas says “there’s still no sign of the coming apocalypse”; that in itself is very much debatable, but on the face of it he wants us to wait until we have a global disaster on our hands before acting – a suggestion so spectacularly foolish that I need say nothing more on it.

More seriously, Tamas has clearly failed to understand that the climate issue is one of minimising risk. There are substantial uncertainties over what might happen in the coming decades, and, yes, some of them are near-apocalyptic, at least for contemporary human civilisation. That might be a low risk, but it is not insignificant, and it includes several quite plausible scenarios which could play out at very short notice. More broadly, there are major impacts which are already at a high risk of occurring over the next few decades.

Tamas goes on to announce that “the temperature data supports the climate sceptics”. This is in fact (unintentionally) correct – the genuine “climate sceptics” are the mainstream climate scientists. Scepticism lies at the core of science: new data is critically examined both in terms of its soundness and against the context of the established evidence. Conversely, those who label themselves “climate sceptics” are usually the opposite: credulous and ill-informed, sucking up whatever factoid they come across on denialist blogs, and resolutely refusing to educate themselves about the big picture. What he’s trying to say is that the temperature data refutes mainstream climate science – a claim which is manifestly and comprehensively false.

If Tamas is able to provide some kind of substantial evidence to back this assertion, I’m sure that climate scientists the world over would be very interested indeed.

Update: Tamas Calderwood then responded in the 16 September edition with this:

Tamas Calderwood writes: Matt Andrews (yesterday, comments) asserts the satellite temperature record is irrelevant because it doesn’t include surface readings or look directly at the troposphere.

First, the surface station record is unreliable because of the urban heat-island effect and appalling maintenance and placement of measuring stations as found by Anthony Watts, but even the data sets that include surface stations show no warming for a decade.

Second, satellites do measure the troposphere and I specifically used the troposphere data from UAH. The troposphere accounts for 75% of the atmosphere’s mass and 99% of its water vapour.

Matt then goes on to discuss “high risk” “plausible scenarios” that ” might happen” — in other words, he can point to no actual serious global warming but despite “substantial uncertainties” he asserts this will be “near apocalyptic … for contemporary civilization”.

Kieran Diment (yesterday, comments) says I ignore 80% of the data but makes no mention of what this 80% is.

Mark Byrne (yesterday, comments) asks if I “will only be convinced of dangerous global warming after it has occurred”? Well, yes Mark, because despite record human CO2 production no dangerous global warming has actually occurred and the Medieval and Roman warm periods were warmer than today anyway.

In the mean time I’ll again point out that the past 30 years has seen a trend increase in Earth’s atmospheric temperature of 0.38C, the past 10 years has seen about 0.1C of cooling and the Argos buoy program shows ocean cooling since 2003. Average temperatures for the past 15 years have been less than 0.2C higher than they reached in the 1940’s and the past 12 months has been around 0.4C warmer than the average since 1901.

This is not a crisis and I don’t think we need to abandon democracy and enslave ourselves to those who know the TRUTH of global warming when the data don’t support their claims of Armageddon.

Update: I responded with this in the 17 September edition:

Matt Andrews writes: Tamas Calderwood (Letters, 16 September) demonstrates stereotypical behaviour from those who label themselves as “climate sceptics”: be uncritically accepting of any argument found on denialist blogs, assume these arguments are better grounded than real peer-reviewed research, and refuse point blank to learn about the big picture of climate science.

His latest letter (in between misquoting me five times) breathlessly repeats a string of endlessly recycled and long-debunked talking points direct from the “Watts Up With That” climate denial blog, infamous among climate scientists for the shallowness and ignorance of its commentary.

For example: “the surface station record is unreliable because of the urban heat-island effect and appalling maintenance and placement of measuring stations as found by Anthony Watts”… in reality, these issues have been long understood and adjusted for, and the real issue – temperature trends – is very strongly correlated across a huge range of surface data sources. For example, the warming trend is just as strong on windy nights as on still nights; if the urban heat island effect were significant, there would be slower warming observed when looking only at windy nights. Big picture: urban heat island and siting issues have a trivial effect on large-scale temperate trend data.

Or “the Medieval and Roman warm periods were warmer than today anyway”: false, false, false, false, false.

And so on and so on. What’s amazing to me is that people can be interested enough in this stuff to devote many hours to digesting wingnut blogs… and yet utterly fail to spend some time learning the basics about contemporary climate science.

Update: Tamas has responded in the comments, so the conversation is continuing here.

Just finished watching a nicely produced TV series called Earth: The Climate Wars. It was originally screened in 2008 on BBC2 in the UK, and as far as I know hasn’t yet been broadcast here in Australia. You can see it in three one-hour segments at stwr.org or in eighteen ten-minute segments at YouTube.

Presented by Dr Iain Stewart, a Scottish geologist at the University of Plymouth, it gives a general audience a nice taste of the world of climate science. Stewart presents well: he’s engaging and personable. His comments on making the series, and the way his views on climate change have changed, are worth reading too.

The first episode mainly looks at the history of climate science up to around 1990. The second covers the “fight back” of arguments against anthropogenic climate change. It looks at what the main criticisms were, and how they were examined and debunked, mainly over the course of the 1990s. The third hour looks at the future: climate models, projections, and uncertainty.

Even though much of the material was familiar, it’s great to see the story retold in a visual, highly polished format. It’s good viewing – well worthwhile.

In the print edition of The Canberra Times of Saturday 15 August 2009, this letter appeared:

Danielle Cronin in her article “Flawed logic used to oppose green Bill” (August 13, p5) stated that Will Steffen declined an invitation to make a presentation along with Professor Bob Carter before the Senate.

That is not surprising, as Al Gore wouldn’t appear and debate with climate sceptic Lord Monckton before the US Senate either.

Do you see a pattern developing here?

Is Steffen afraid that he won’t be able to hold up his end in a debate?

You can bet on that.

The alarmists have only computer climate models (fantasy computing) to use as evidence and that is no evidence at all.

Is there evidence of a vested interest in supporting this foolish theory?

John McKerral
Batemans Bay, NSW

My response:

John McKerral (Letters, August 15) tries to condemn modern climate science in general because Will Steffen, an eminent climate scientist with the ANU, declined to debate the discredited Bob Carter face to face in front of the Senate. I can’t speak for Steffen, but I can understand why he wouldn’t. It’s similar to the situation with creationists: they are utterly lacking in genuine scientific evidence for their position, but they can score points through the strange compressions and distortions of face to face debate, where verbal agility, cute anecdotes and one-liners win the day. Science doesn’t work that way: conclusions are carefully built up from a large body of thoroughly documented and widely-reviewed evidence. Debating whether the world is warming, and whether humans are mainly responsible, makes about as much sense as spending Senate time on a debate over whether smoking causes cancer.

McKerral also asserts that climate science has nothing more than computer models as evidence. This is not just incorrect; it’s the diametric opposite of reality. The observational evidence supporting the conclusion that the world is warming, and that human activities are the primary cause, has moved beyond being a mountain; it is now better described as a mountain range. On the other hand, the evidence of any substance against it is, to a first approximation, non-existent. That’s the scientific picture, and it bears little resemblance to what passes for analysis in many a dingy corner of media commentary and politics.

Matt Andrews, Aranda

A long thread of letters in The Canberra Times print edition, centring on curious claims by Tim Curtin.
First this letter appeared on Friday 31 July 2009:

The article “No time to lose as climate change turns to the worse” by Will Steffen, director of ANU’s Climate Change Institute (July 27, p9) contains some questionable statements as “fact”.

Steffen asserts “the climate system is now moving faster than we had thought likely a decade ago… the rate of accumulation of carbon dioxide in the atmosphere has increased since 2000 because of the growth in the global economy and the relative weakening of the natural processes that absorb carbon dioxide from the atmosphere”.

These statements are incorrect. The rate of growth of annual net increases in the atmospheric concentration of carbon dioxide was 7.44 per cent a year from 1960 to 1969, 10.01 per cent from 1970 to 1979, 7.16 per cent from 1980 to 1989, 4.55 per cent from 1990 to 1999, and just 2.8 per cent from 2000-2009 (the rates are for the years ending in June). Thus growth of net increases in atmospheric CO2 has been much slower than at any other time since records began at Mauna Loa in Hawaii in 1958.

It follows that while Steffen is right about rapid growth of the world economy from 2000 until 2008, he is wrong to say that “relative weakening of the natural processes…” explains his assertion that “climate change is turning for the worse”. The evidence is for strengthening those natural processes, namely the annual increase in photosynthesis that has accounted for more than half of all anthropogenic emissions of CO2 since 1959 – and explains the decline in the growth of those net emissions to Steffen’s “atmospheric accumulation”.

Tim Curtin, associate, RMAP, ANU

This was followed by assorted replies (including one from RMAP saying that Curtin was not in fact an associate of RMAP at all!).

Curtin then responded on 7 August with this:

Nick Ware (Letter, August 4) challenges my demonstration (Letters, July 31) that growth rates in atmospheric concentration of carbon dioxide have declined from 1960 to 2009.

He suggests I was using the “third derivative” – I wish I knew what that is! I simply derived the semi-logarithmic growth rates for each decade, those being the first derivative, like a normal compound interest growth rate over the period in question. The second derivatives (ie, the rate of change of the rate of change) also decline if you can be bothered to calculate them (unlike Will Steffen).

More seriously, Steffen in his article in The Canberra Times (“No time to lose as climate change turns to the worse”, July 27, p9) and in his piece (co-signed by 15 other worthies) in The Sydney Morning Herald (August 1) relies on James Hansen’s temperature data (NASA-GISS) which relies almost exclusively on temperatures measured at airports with ever-increasing planes, people and parked cars.

The truth is that at Mauna Loa where the atmospheric carbon dioxide level is measured, there is virtually no discernable trend in temperature since 1958, and none at all since 1978.

Finally, I must confess that when I signed my letter of 31 July I thought I was still an associate (unpaid) of RMAP at ANU. Sadly that is not the case, but even if I had been, I should not have used that designation.

Tim Curtin, Spence

My response:

Tim Curtin (Letters, 31 July and 7 August) makes a series of basic errors in his statements on climate change. The first is that it would make sense to measure the growth in carbon dioxide as if it were like compound interest. It doesn’t. Back to basics: CO2 increased by an average of 0.85 parts per million each year during 1960-69, by 1.27ppm for 1970-79, 1.60ppm for 1980-89, 1.50ppm for 1990-99, and by an average of 1.87ppm a year for this decade. There’s a clear long term trend here: the CO2 level is going up, and over time the amount it’s increasing by each year is growing. We’re already at around 390 parts per million: a higher level than humans have ever experienced, and already higher than the 350ppm that is increasingly regarded as the probable safe level for ecological and climatic stability.

Another error is the implication that the entire body of land surface temperature data – as used by NASA-GISS, Hadley, and many other climate science centres – is suspect, with the assertion that they rely “almost exclusively on temperatures measured at airports with ever-increasing planes, people and parked cars.” This is broadly known as the “urban heat island effect”, but it is well understood in meteorology and climate science, and temperature data is correlated and carefully adjusted to account for it. A series of studies published in Nature in 2004 compared temperature readings taken on calm nights with those taken on windy nights. The urban heat effect should be much stronger on calm nights, but the temperature trend was very strongly correlated. Overall the adjusted temperature data is sound, and is not undermined in any significant way by urban heat effects. The evidence for the warming trend is so strong that it’s essentially incontrovertible at present.

It’s amazing to me how armchair experts who clearly are not familiar with the science so often have the hubris to believe that they have some extraordinary insight that instantly overturns the entire scientific consensus. In reality, natural sciences don’t work that way. It’s all about the building up of many layers of evidence from a wide range of research teams, data sources, and physical systems, and arriving at conclusions based on the balance of probabilities. To date, there is no substantial evidence that constitutes a serious challenge to the mainstream science. The level of noise in the media from those who refuse to concede that humans are in the process of causing severe climate disruption is utterly out of proportion to their scientific strength of their arguments.

Matt Andrews, Aranda

A letter appeared in The Canberra Times print edition of Saturday 1 August 2009:

Mark Diesendorf begins his article, “It’s power to the people on climate change action” (July 29, p11) with the cliche that all alarmists love, “Global climate change is accelerating”. I assume he means warming. That is simply not true. But as a scientist I cannot accuse him of lying because nothing in science is ever “settled”. But I am entitled to ask him on what evidence he bases his claim, and on behalf of CT readers I do so herewith.

Aert Driessen, McKellar

It refers to an earlier article by Mark Diesendorf (which is not online, due to The Canberra Times‘ ludicrously poor approach to online material: most opinion pieces and a lot of the print content is never made available online).

My response, published on 4 August:

Aert Driessen (Letters, August 1) asks for evidence that global warming is accelerating. Firstly, what does the word “climate” mean? It means the long-term average of the weather, generally defined to be over periods of 30 years or more. Temperatures have a lot of short term variability: they bounce up and down from year to year. The important aspect is the long term trend.

Taking the most commonly cited data for global temperature, from the Hadley Meteorological Centre in the UK, the picture is clear. Annual averages, dominated by short term variability (the “weather”), bounce up and down all the time, but 30-year averages, showing the underlying trend (the “climate”), have been rising since early in the 20th century, and especially since about 1975.

Specifically, the 30-year average shows a warming rate of 0.88 degrees per century in 1989, a rate of 1.10 degrees per century in 1999, and a warming rate of 1.52 degrees per century in 2009. Looks like acceleration to me.

Matt Andrews, Aranda

A note on the details of the above figures: I drew the annual global average temperature data from HadCRUT3 (combined land and marine surface temperatures), then calculated the 30-year averages (what I describe as the “climate” as opposed to the “weather” annual averages). The warming rates I cited are the average for the preceding 10 years in each case. So “0.88 degrees per century in 1989″ means that the average annual rate of increase in “climate” temperatures over the ten years to 1989 was at a rate of 0.88 degrees per century. I should probably have made it clearer by rephrasing it like this:

The 30-year average shows a warming rate of 0.88 degrees per century during the 1980s, a rate of 1.10 degrees per century in the 90s, and during this decade we’ve seen a warming rate of 1.52 degrees per century.

Australian Senator Steve Fielding has attracted quite a bit of media attention with his series of stunts aimed at building doubt over the scientific basis for anthropogenic global warming.  The core of his campaign has been a carefully constructed graph which shows no clear rise in temperatures while CO2 continues to rise since 1995.  The implication is that the world is not warming and CO2 is not (directly) related to temperature.

Trouble is, he (apparently) thinks he’s looking at climate – but he’s not.  He’s looking at the weather.

Climate is defined as the long-term average weather, where “long term” is generally accepted to mean at least 30 years.   Anything on a shorter time scale is dominated by short term variability: weather.

The graph Fielding cites shows year-by-year data: annual average global surface temperatures.  So each data point is the average of a one-year period.  That’s a nice picture of the weather; but why don’t we take a look at the climate?

Here’s a graph from the same data set (Hadley CRUT3) showing the annual average temperature (the brown spiky line, jumping up and down all the time) and the 30-year average temperature (the smooth yellow line).

Brown = weather.  Yellow = climate.

Clear?

A surprising letter in The Canberra Times print edition of Saturday 4 July:

I thank Matt Andrews, of Aranda, for sharing with the people of Canberra his great wealth of knowledge concerning climate change.

It is clear to readers of his authoritative letters that he is a detached academic with many letters after his name, unlike those who simply regurgitate read material or merely express an opinion.

Along with Crispin Hull I feel for him on his nightly agonising about those exploiting scientific illiterates who disapprove of current climate science.

Bob Edwards, Kambah

Well, my thanks go out to Bob Edwards for this unexpected praise.

However, I should point out that I’m neither an academic nor do I have any letters after my name… I’m just an interested bystander.  I’d dearly like to devote my time to the study and practice of climate science, but for now I’m merely a humble web developer with an occasional bee in the bonnet.

An amusing follow-up letter arrived in the Tuesday 7 July print edition:

Bob Edwards (Letters, July 4) condemns himself and proves a point that climate scientists (the sceptical ones) keep trying to make.  When he pours adulation on to Matt Andrews (and Crispin Hull) for their alarmist views on climate change and then uses derogatory language to belittle and ridicule those with another view, he is not contributing to the debate but defending religious dogma.

Aert Driessen, McKellar

Fairly standard denier tactics: try to frame the mainstream science as “alarmist” (or “religion”) and to give the impression that there are two substantial sides to the scientific debate.  Sadly this perception is a long, long way from where the science actually is.

Given the strength of the evidence for anthropogenic global warming in general, this is now essentially the same as a tobacco lobbyist describing the suggestion that cigarettes cause cancer as “alarmist”, or an anti-vaccination crusader damning the conclusion that vaccination can be effective against disease as “religious dogma”.