Tuesday, 1 December 2009
Either we deal with it or it will deal with us.
There is no serious challenge to the science behind climate change. The whole basis for the denial movement is not attacking the science, but attacking the scientists. Look for a real scientific paper attacking the science. There is a very small number of these, all of which have been debunked. Most other material is on blogs and the opinion papers of the mass media, replete with the language of personal attack. Climate scientists are "alarmists", "warmists", "catastrophists", and any other number of made-up appellations.
As with the tobacco and HIV denial movements, personal attack does not prevent the ultimate harm that denial of the facts causes.
Unlike tobacco and HIV, we are not talking about something that will ruin the lives of a few million people if not dealt with expeditiously. Rapid climate change is causing a rapid acceleration of extinction rates. The rapid depletion of the Himalayan glaciers threatens the food supply of a half a billion people: melt water from these glaciers feed major river systems of both India and China. And reduced agricultural output is likely to be worst in poorer countries.
Talk therefore of whether an emissions trading scheme should be contemplated in the absence of any serious alternative is crazy. The Australian government's scheme falls far short of any reasonable solution, but their main opposition is opposing it without offering an alternative.
Given that, how will climate change deal with Australia?
There are two possibilities: Australia's inability to face up to the problem could be a worldwide phenomenon, in which case we face a period of growing environmental disaster: death of the Great Barrier Reef, collapse of food supply in India and China, famine in Africa. If on the other hand the rest of the world gets its act together, Australia as the world's biggest coal exporter and the country with the highest per capita CO2 emissions will be left high and dry, and as uncompetitive as a country that did not foresee the trend away from horse-based transport a century ago.
Wednesday, 25 November 2009
Let's focus this time on the comments, since I had a letter published.
First, Greig, a regular contributor:
Philip Machanick in the past you have vehemently argued that it is CO2, and not the sun, which is the major driver of observed global warming. And now, year after year, global temperatures stubbornly refuse to climb in correlation with CO2, and so you revert to using the sun to explain. Like Dr Kevin Trenberth you are wedded to an opinion which you want the data to fit, and like him you saying “there should be even more warming . . . the data are surely wrong.”
Greig, CO2 drives the trend for the simple reason that there is no trend in natural factors, whereas atmospheric CO2 is increasing exponentially. The science says there's a logarithmic relationship between climate sensitivity and CO2 levels, implying we should over the long term see a linear increase in temperatures if the basic science is correct. The purpose of detailed models is to narrow the range of uncertainty, not to predict the basic effect. We are currently at a solar low, but the multi-decadal trend in solar insolation is flat. Same for ENSO. We had a big El Niño in 1998 and more recently a La Niña. The net effect of these things is zero, but pick a time when they are all pointing up or all pointing down, and you get a short-term high or low. Trenberth's comments were in a private email, a musing with colleagues, who pointed him to evidence that he was wrong. Much as I am loath to use stolen material, since it's out there and being misused, here is one of the responses by a colleague to Dr Trenberth:
I look at this in two ways. The first is to look at the difference between the observed and expected anthropogenic trend relative to the pdf for unforced variability. The second is to remove ENSO, volcanoes and TSI variations from the observed data.
Both methods show that what we are seeing is not unusual. The second method leaves a significant warming over the past decade.
Next, Ian 11:39am (you will have to page through the online comments to find all of these):
Philip Machanick Did the models predict that the global temperature increase would lessen over the last 10 years?. That these years are the hottest 10 since whenever really isn’t a valid argument despite those such as v who claim it is. Fact is that the increase over the decade has been less than predicted. Now why is that? [snip] And incidentally Professor Latif who is a climate scientist, has made and is still making comments that suggest the world is not about to turn into a heat ravaged dust bowl just yet
No, the models do not make predictions for as short a period as 10 years. But see above about removing known effects like ENSO. See also here how solar output does not correlate with temperature as it should if there were no interfering artificial effect, and another very clear illustration here of how temperature and solar output have diverged. Also, I illustrate that you can add a strong artificial upward trend to a temperature record that is essentially flat and still find a 10-year period with a strong downward trend.
You are wrong in your interpretation of Latif's comments, as I've indicated before on this site and in more detail elsewhere.
Philip (not me) 2:27pm:
Gosh all these people ignoring the hacked emails and documents showing what nasty little con artists the CRU are. In ignoring them they are behaving just like ahh… I don’t know maybe like holocaust deniers.
Or maybe they don't agree with the principle of stealing private communications? How about challenging the deniers to reveal all their emails for public scrutiny? That would make for interesting reading. Things colleagues say between each other are often unguarded, said without thought as to correctness or unintended consequences. Why should we all take exquisite care in every private conversation that we don't ever say anything we don't really mean, in case someone is eavesdropping? What kind of world would that be?
de Brere 01:27pm
Philip Machanick. Spot on, you do validate a theory by testing its predictions against observations. However, the prediction-observation link needs to be 100% accurate once other factors are taken into account. Otherwise the other unknown or unaccounted factors may themselves be the source of the observed variation, and not the theorised cause; in this case, GHGs. In that respect, all the tens, hundreds of billions invested in the “science” of AGW in the last two decades has spectacularly failed to come up with models that provide even moderately accurate prediction (or explanation) of observed climate change; far less of the individual weather events that go to make CC up.
De Brere, I've covered your misconceptions about how science works earlier. For your benefit I'll summarise again briefly here. Science in the real world is never 100% exact. Handling errors and uncertainties is a standard part of applied science. If you want exact answers, do pure mathematics. As for these astronomical numbers for the cost of climate research, what are your sources? I found a comparison of current US military and climate change-related funding and:
- excluding the recovery package, US military spending outranks climate spending 90:1
- even within climate spending, much more is spent on energy that on climate science
And finally, climate science is not about predicting tomorrow's weather. ENSO and the solar cycle are not fully understood, and have a bigger short-term impact than increasing CO2. However, if you keep increasing greenhouse gases long enough, you create a trend that breaks out of short-term variation. Where's your evidence that that is not happening? How do you explain that contrary to the strong downward pull of natural factors the last 10 years or so, the temperature trend is still slightly up?
Having dealt with comments about my letter and comments, I'll let Stephen Morgan 05:47pm have the last word:
Okay - so apparently these hacked emails are SO important that they change the case. So, can somebody tell me what they say. Only not just the ones that apparently give reasonable cause to doubt a few scientists, but every single one of these thousands of emails?
If you think the emails matter, then you will obviously review ALL of them, understand the context of ALL of them, be able to balance the views presented by ALL of them, and be able to come up with a reasonable theory that is supported by the contents of ALL of them.
To do otherwise is selective, prejudicial, and inevitably driven by a desire to support or discredit a specific cause rather than to seek any reasonable explaination.
It’s called denialism for a reason - it is the methodology of those who seek to deny rather than to discover, to obfuscate rather than to explain.
AGW IS widely accepted because it IS widely understood by those who support it. It is popular because it is far more reliable and consistent than any other option.
Is it proven - NO! Is it undeniable - NO! Just do as I asked - come up with something positive that offers an alternative, not just continued hackneyed attempts to sink a battleship with a pin-prick!
Wednesday, 21 October 2009
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.
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.
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.
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.
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.
Sunday, 11 October 2009
I have some nice organic tomatoes from a farmer’s market, a little left over Regianno Parmesan and some supermarket spinach and ricotta tortellini (the fresh kind, not died). On a less lazy day, I’d crank up the pasta machine – but not today. For dessert I have about 200g of good fair trade dark cooking chocolate, and some milk and eggs in the fridge.
To get started, how about a nice sauce for the pasta? Let’s see what else I have and put it together (enough for two serves):
- a splash of olive oil
- a shredded clove of garlic
- bottled herbs (basil, parsley) – it’s raining, I’m not going to the garden this once
- a sprinkling of macadamia halves
- 4 smallish tomatoes
- a hint of red pepper seeds
- finely shredded Parmesan
The trick with a tomato-based sauce is to squeeze out the juice and seeds. This way you don’t have to cook it down so much and end up with a fresher taste. Start with heating the oil, toss in the garlic then the tomato, herbs and spices. Then the tomato has almost fallen apart, add in the macadamias.
At this point, you may want to add in a splash of good red wine: not too much, you’ll want to drink the rest.
Once the sauce is making good progress, cook the pasta. The brand I’m using (a local one, San Remo) is not half bad if you ignore the package directions to cook to death for 6 minutes. My rule for any filled pasta or gnocchi is (based on instructions from an Italian cook): “cook them until they give up” – when they float to the surface and turn upside down. This time, it’s about 2 minutes. The result: a good chewy texture, and a filling that still has plenty of taste. Australians (judging from the package instructions) share the South African and British taste for flavourless mush.
Toss the pasta in the sauce, add Parmesan and you’re ready to serve.
On to dessert. This needs a little planning ahead of time. I like to make meringues at the same time as I make ice cream because you can use the egg yolks for the ice cream. There are a few simple basics for making good meringues:
- never use chilled eggs: let them warm to room temperature
- use a copper mixing bowl: this seems to result in getting a stiffer texture much faster (I doubt very much a little copper is toxic: think of what they replaced lead with in water pipes)
- cook at low heat (90°C or 190°F for the neoliths): you are drying the meringues more than cooking them
Here’s another interesting trick I discovered. I recently found brown caster sugar in a supermarket and bought it wondering why you’d want something like that. The answer is, you get extra crispy meringues that whip up easier. The colour is a pale gold rather than snowy white, but they taste great.
OK, so the ice cream. The basic idea is to make an egg custard, let it cool, chill it, add whipped cream then churn in an ice cream maker.
Here’s an example:
- 400 ml milk
- quarter cup of sugar (double this if not adding something sweetened)
- 3 egg yolks (reserve the whites)
- 200g good dark chocolate (fair trade please: if you are going to die of death by chocolate feel good about it)
- 200 ml good whipping cream
Shred the chocolate. I do this by slicking it finely: it shreds as you slice.
Whip up the egg yolks, gradually adding the sugar, until you have a light consistency.
Scald the milk in a microwave (2 minutes in mine; it needs to be just short of boiling). Add some of the milk into the egg mixture, mix well and whisk into the rest of the milk. Heat again in the microwave for 2-3 minutes, watching for the point where it starts to froth up. Stop and whisk vigorously as soon as this happens, and repeat until you have a thick custard. If you take it too far, you end up with sweet scrambled egg, so take care.
At this point, patience is called for, otherwise you might as well decant into mugs and serve as the world’s best hot chocolate. If you can resist, put the custard aside to cool off, then refrigerate it. Lunch is developing into an all-day affair.
While you have nothing else to do, work on the meringues:
- 3 egg whites
- 125 g sugar
Whip the egg whites to a froth, then gradually add the sugar. Whip until the mixture can hold its shape, then drop about half a tablespoonful at a time onto a nonstick baking sheet in a baking tray (I use the baking sheet as anti-crunch packing when I store the meringues, and reuse it a few times for future batches). Put in a cool oven (90°C) on the middle shelf for 3 hours, and leave in the oven after turning off the heat to continue drying.
Back to the ice cream. Once it’s thoroughly chilled, whip the cream fairly stiff, fold it in then put the mixture in an ice cream maker (mine is hand-churned). Work the machine the usual way. Although ice cream is one of the few things I eat from frozen, it’s best eaten fresh.
Sunday, 23 August 2009
The movie starts with a mystery: it has no hint as to why the aliens arrived. All we know is that they have lost their ability to control most of their vastly superior technology (not quite all: a few of their weapons work but only in contact with alien DNA, and their space craft is able to remain in a fixed position for decades). There appears to be some linkage between their genetic make up and their ability to control their technology, but much of this is left a mystery.
By a combination of hand cam shots meant to represent an official record of events, news-like footage, surveillance camera-style footage and the occasional realistic scene, it’s hard not to become involved and have a real sense of an actual story unfolding, even though the earlier events are in the past.
Imagine humans in a like situation. A million humans in a colony ship arrive at a distant planet, and our technology breaks down. Aliens who are obviously less advanced than us “rescue” us from our disabled ship and treat us like dirt. How would we cope? How many of us would have the advanced scientific knowledge to fix our broken space craft? Think Star Trek episodes and beaming down to the nearest planet to find some broken part or find a missing chemical. Totally unlikely. What we saw in District 9 is a much more likely scenario for a space ship breaking down far from home. Possibly this is why (though the last Star Trek movie was passably good, give or take the odd plot hole you could drive the Enterprise through) my favourite SF movies tend to be spoofs like Mars Attacks! and Galaxy Quest.
The real genius of this movie is in its use of role reversals. The aliens have arrived in a disabled space craft under squalid conditions (Australians, think refugees in leaky boats). They are treated with utmost condescension, and things that are obviously not for their own good are done to “improve” conditions for them. Suddenly you are put in a position of seeing this all from their point of view. You need a good understanding of South Africa to get all the references but for a foreign audience it adds to the “alienness” feeling of the movie. To add to the subtle feeling that you are looking at things backwards, one of the aliens is called “Christopher Johnson” (typical of the way colonial overlords renamed the natives when they couldn’t pronounce the native-language name), a name less “alien” to a non-South African audience than Van der Merwe.
Let’s examine some of those South African references. First, the very title harks back to the dark years of apartheid. District 6 in Cape Town (in a different part of South Africa) was a ghetto for Coloured (mixed-race) South Africans, which, despite poverty, had a strong sense of community. The government decided to clear out the residents because having Coloured people too near the city centre was inconvenient. Clearing out District 6 was a big running sore in apartheid history; forced removals were bitterly opposed, and the cleared land was left largely undeveloped until the fall of apartheid, when rights of former residents to return were recognized. Forced removals, in general, were a key feature of the apartheid system. One study of the effects was called the Surplus People Project; a movie depicting the effects was titled Last Grave at Dimbaza.
Second, the attitude towards the aliens is consistent with current attitudes in South Africa to “illegal aliens” of the human kind. There have been riots over the presence of such foreigners from poorer parts of Africa, and the attitudes expressed in the movie are absolutely typical, and a sad rejection of the apartheid past, when the rest of Africa rallied to support of the anti-apartheid cause, and accepted South African refugees with open arms. The aliens are accused of all kinds of things like causing crime, when the only evidence we see of criminality is from Nigerian gangs and the MNU company that is desperately trying to make money out of the aliens by any means, not matter how unscrupulous. MNU is a bit of a composite, not reflective of a real company. Americans may relate it to private contractors in Iraq. South Africa does indeed have a large armaments company, government-owned Denel (a relic of the apartheid era) but it does not do the sort of private security work depicted in the movie – there are other South Africa companies that do that sort of thing – nor is it as big in the world market as the fictitious MNU.
Third, and this is where the subtleties really accumulate, the attitude of protagonist Wikus van der Merwe to the aliens is exactly the way apartheid officials treated Black South Africans in the darkest apartheid years. Telling one of the aliens not to use so many clicks is a direct reference to South African languages, several of which include click sounds (the San languages are almost entirely composed of clicks, and Xhosa and Zulu have a few click sounds). That Van der Merwe, who obviously gets on well with his Black colleagues, can get away with this treatment of the aliens with no sense of irony or objection from the Black members of the team shows how little the South Africans represented in the story learnt from their apartheid experience.
More sensitive viewers may dislike the violence (especially in the second half, which turns into frenetic action scenes) but it is integral to the story and not gratuitous. The dialogue also includes some of the more serious Zulu cursing I’ve heard in decades but that would go over the heads of most foreign audiences.
No doubt the computer game heritage of the movie gives it some of its mass market appeal, but this is a real classic, as much a game-changer (in the other sense) as the Matrix movies, and a whole lot more intelligent. That there are almost no American (or even UK English) accents in the dialogue, some African language dialogue without subtitling and that the protagonist has a name almost unpronounceable to non-South Africa English speakers are brave moves but add to the movie’s appeal as something different from the usual Hollywood dross.
A little help for the foreigners: “Wikus” is pronounced something like Vee-cuss. “Van der Merwe” is pronounced something like Fun-deh-meh-vuh.
Sequel? Very likely. With the box office this one is generating, the unexplained details and the potential for follow-up developments left open at the end, a sequel is almost 100% on. I hope it’s as good as the first. At last, after a long drought, an SF movie that’s better than a parody. It’s been a long wait.
Sunday, 16 August 2009
A few days ago, in online comments to a letter of mine in The Australian, someone made the claim that climate science can’t be any good because it is inexact:
Philip. With all due respect, if anyone, it is you who are confused; at least about what science is, and in that, you are certainly not alone. Science is not based on correlation but on causation, and an understanding that if A causes B, then A and B move in absolute lockstep according to a precise mathematical law; like Newton’s F=ma. It is not F~ma. Where there is the most minute variation, science says that there is a causal factor for that variation, and a further law to absolutely and completely describe that variation; eg via Einstein’s E=mc*c. Note too that this does not change the original law; it still applies, but it introduces and accounts for another factor which can affect a factor of the original law. It is also worth noting that this new law actually predicted variations from Newton’s laws that were so minute they had not yet been measured. With both together then, everything remains exact. That is true science.
Contrast that to the greenhouse “science” laws (based on correlation) to which you refer. They predict that for a doubling of CO2, there will be between a 1.5 and 4.5C T rise. To in any way equate that to true science is just wrong; for comparison, it would be like having Newton’s law saying ma<F<3ma. Einstein’s Law would then have to be something like E=ms*s (s=speed of a snail crawling over sand) to account for that sort of variation. A hydrogen bomb would then not create enough energy to lift your hat, and the sun would be so weak that earth T would be about -273K, even when the variation in gravitational force brought our orbit within a few million k of the sun!
I know this sounds silly, but I use it to emphasise that real science is exact and absolute, because there is no correlation in it; only causation. That is what climate science needs to be before it can be taken seriously outside of political and religious circles; based on causation, not correlation.
First, greenhouse gas theory is not based on correlation. It is based on radiative physics. The logarithmic relationship between increasing CO2 levels and increased temperature was discovered by Arrhenius and demonstrated in the lab in 1897. The radiative physics needed to calculate the effect accurately was discovered early in the twentieth century. There is therefore as exact a measure of the effect of increasing CO2 as any of Newton’s Laws. What makes things more complicated is the fact that we are dealing with a real-world application, where exact measurement is not possible, and there are many other confounding factors to take into account in making exact predictions.
Rather that go into all this again, I will illustrate just how far from reality the commenter’s view of how “exact” science is in another area. Newton’s law of gravitation is about as exact a formula as you could want. While general relativity corrects it, if we are doing something as mundane as designing a bridge or navigating a space probe, Newton’s law is so close to accurate that we can assume it is exact. In principle, navigating a space probe is not terribly hard. The most efficient way of doing it is to burn a rocket until the probe achieves escape velocity, while making sure it points in the right direction, then leave it to drift. To make things simple, let’s assume we only want to navigate accurately past any one location, and anything else on the way is a bonus (except a collision, but let’s ignore that to keep things simple).
We have a formula for gravitation (thanks to Newton) that says we can calculate the force on any two bodies in space as a constant times the two objects’ masses over the square of the distance between them:
G is a constant, M1 and M2 are the masses of the two bodies, and r2 is the square of the distance between their centres of mass.
For our navigation problem therefore, things look very straightforward – until we get to the detail. We don’t just want to know the forces that apply to the space probe at an instant but how its motion is affected over its entire journey. To make things harder, the space probe isn’t the only thing moving. The entire solar system is in motion under the influence of gravitational forces of everything else in the solar system (and other more distant objects, but the inverse squared law makes that an insignificant correction). In theory we could set up a bunch of differential equations to solve exactly but there is a practical problem with doing this for so many different bodies. There are over a million asteroids for a start and even without them, the differential equations would not be practical to solve. So in practice what you need to do is to approximate the parameters at a given time, calculate where everything will be at some later time (soon enough not to loose too much accuracy, but not so soon that the amount of calculation is prohibitive), and keep applying these steps until you arrive at the time when you need to know where your probe will be.
Let’s just look at how difficult this is for one body in space. Assume we have a series of measurements of where this body is, culminating in the positions I’ve labelled here as A and B, measured at times tA and tB – with the aim of working out where it will be at a future time, tC:
So how do we work out where the body will be at time tC? Based on previous measurements, we estimate the speed and acceleration of the body as it passes through position B, and apply Newton’s formula to adjust its acceleration, resulting in calculating that the body will be at position C. Unfortunately because our previous measurements were not 100% accurate, the actual position the body ends up in at time tC is position D, a little out from our calculation.
How could this happen? The previous measurements of where the body was hadn’t taken into account gravitational forces fully. At some point, you don’t know where every body is going to move next, and have to make some approximations before you can start exact calculations. Why? Because to calculate the effect of applying a force to an object you need to know three things at the time immediately before you apply the force:
- its position
- its speed (velocity)
- its acceleration
Applying the force alters the body’s acceleration and (assuming no other forces are involved), if you know all four quantities precisely (force, acceleration, velocity, position) you can calculate where it will go next precisely (until the parameters change). However if there is any error in any of the parameters to the calculation (including the force, which for gravitation relies on having the positions and masses of all other objects right), the answer will not be exactly right – despite the use of an exact formula.
Worse still, because time tC is in the future, between time tB and time tC, everything else has moved, making any calculation based on the gravitational effects of the positions of everything else at time tB inaccurate. Point C should be marked as a circle representing the uncertainty in the calculation, or a fuzzy blob if you want to represent the fact that the most likely location is at point C with diminishing probability of the position being at a location further out from point C.
Even assuming you can arrive at a tight enough approximation to the position, velocity and acceleration of all objects in the solar system to sufficient accuracy at a given time, you need to recalculate all the parameters for successive time intervals, applying the gravitational force each time to get fresh parameters. This is where things get really hairy. We have around a dozen objects big enough to call planets or large moons and over a million asteroids. Even with a large-scale computer to recompute the position in space of each object along with its new velocity and acceleration, we would have to do trillions of calculations just work out where everything has moved, even if we only do this once. Why? Because for each body, we must calculate the effect of every other body. If there were exactly 1-million such bodies, that would mean almost a million times a million applications of Netwon’s formula. This is clearly impractical, especially if we have to repeat the calculations many times to get an accurate projection of the probe’s trajectory.
Fortunately, there’s a better way. If a group of bodies is far enough away, treating them as a single body with a position based on their centre of mass is a reasonably accurate approximation to their contribution to the gravity computation [Barnes and Hut 1986]. This picture illustrates the basic concept (in two dimensions to make the picture easier to understand):
Depending on the sensitivity parameters of the calculation, it may be possible when calculating the forces at A to proceed as if there were a single body at each of locations C and E. The body at D on the other hand may be too close to C to allow this approximation.
The upshot of all this is that although we can in theory calculate gravitational forces extremely precisely, in the real world, any practical calculation has to contain errors. We can limit those errors by taking more measurements, taking more precise measurements, and reducing the approximations in the calculations at the cost of slower computation. Our space probe can be placed to within some reasonably accurate window of its intended destination, but it had better have a little fuel on board for course corrections.
Back now to climate models.
The situation is really not so different. The relationship between CO2 increases and temperature increases can be measured accurately in the lab, but effects on the real world require approximations because measurement is inexact, we have fewer data points than we’d like and accurate computation would take too long. But as long as we have a handle on the scale of the errors, we can work these into the computation, and produce an answer with a central value and a calculation of how much the actual answer could vary from that central value. This is not some strange new principle invented by climate scientists. Any science of the real world is necessarily inexact, for similar reasons to those that apply to the gravitation computation. As with any other area of science that requires complex accounting for the real world, an answer may be inexact, but not so inexact as to be useless for policy makers [Knutti 2008].
So what of the “correlation is not causation” mantra, which so often accompanies objections to climate science? Simulating the whole earth’s climate is not done using correlations. To claim this is ignorant or dishonest. The simulations are based on laws of physics and measured data (with the sort of simplification, handling of noisy data and approximation needed to do any real-world science) to predict a trend. Comparing that predicted trend against actual measures certainly can be done using correlation, but that is not the only test of the theory – nor should it be. In any case, if you have a mechanism and then look for a correlation, that correlation can hardly be said to lack causation. To claim blindly that correlation is not causation (as opposed to the more reasonable position that you should be cautious to claim causation if correlation is your sole evidence) is more or less to say that whenever you find a correlation, you must dismiss the possibility that there is a causal connection, which is clearly absurd.
[Barnes and Hut 1986] J.E. Barnes and P. Hut. A hierarchical O(N Log N) force calculation algorithm. Nature, 324(4):446-449, December 1986
[Knutti 2008] Reto Knutti. Should we believe model predictions of future climate change? Phil. Trans. R. Soc. A, 366(1885):4647–4664, 28 December 2008 [PDF]
Thursday, 13 August 2009
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
Wednesday, 22 July 2009
I am guessing here at the specific book “Malcolm” has used as source material but I won't name it since he doesn't (he mentions the author's name, Plimer, but I don't have the book I’m thinking of in front of me so I will take it as Malcolm’s contribution; if anyone has the Plimer book, feel free to comment on the “Malcolm” interpretation).
This whole thing reminds me of the Monty Python Hungarian Phrasebook sketch, in which pranksters have published a phrasebook rendering commonly-used tourist questions from the original Hungarian into inappropriate English (e.g., “Can you direct me to the railway station?” in Hungarian is translated to “Please fondle my buttocks.”).
Let’s look at some of “Malcolm’s” quotes from his phrasebook (approximate page numbers from the PM’s blog; they shift around as responses go up):
- [p 85] The warmest year in modern times was 1934. The next three warmest were 1931, 1938 and 1939. All before humanity’s latest industrialisation with higher CO2 production. Other warm years: 1998, 1921, 2006, 1999 and 1953. Uh, no. The Hadley data set HadCRUT3 shows that 1998 was 0.7° warmer than 1934. The source of “Malcolm’s” error is NASA’s correction of their US data set, that has been misrepresented around the blogosphere as a significant change in worldwide trends. No data set that anyone takes seriously does not show significant warming over the twentieth century.
- [p 81] Other likely climate drivers in the solar system include variations in: solar system centre-of-gravity; sun’s centre of gravity; Earth's orbit and distance from sun; Earth’s axis tilt and precession; moon’s orbit; sun spot cycles and solar irradiance or energy output; ...........
The IPCC’s mandate prevents considering these and other natural climate drivers. Why? The IPCC is not a scientific organisation, it’s political. Rubbish. Read the IPCC's report Understanding and Attributing Climate Change, easily found by searching for attribution of climate change, and you will find this claim is completely false.
- [p 89] Krakatoa’s 1883 volcanic explosion dwarfs humanity’s CO2. Nature rapidly absorbed Krakatoa’s sudden, huge CO2 into oceans and biomass, quickly rebalancing Earth’s atmosphere. False. Krakatau in 1883 is estimated to have produced 9.1x1011 moles of CO2. One mole of CO2 is 44g so this amount of CO2 is about 40-million tonnes. The latest figure I can find for total human carbon emissions is 8,230-million tonnes of carbon in 2006, or about 29-billion tonnes of CO2. So in one year, total anthropogenic CO2 emissions are more than 700 times the amount Krakatau vented in 1883.
That’s all I have time for. Be assured, there is a lot more where these came from.
Tuesday, 14 July 2009
Let us be clear about this: some have said, what’s the big deal? Mac or Linux users are no worse off than people without computers who also lose out on the benefits of eTax. That’s not the point. Someone buying a popular (if not the most popular) computer platform may have their choice swayed if a major, mainstream application is not available. If you want to use a Windows machine, a Mac or a Linux system, you have good options for spreadsheets, word processing, email, web surfing, personal accounts etc. on all of them. A government agency such as the Tax Office ought not to be swinging competitiveness of rival computing platforms towards creating a monopoly.
If you want to make your voice heard, here are two things you can do:
What will I do with the petition? Once it’s reached 1,000 signatures I will alert the ATO, Wayne Swan, Joe Hockey and Bob Brown as to its existence. I will challenge each of them to take action.
The results count below includes a few bogus signatures that I’ve trimmed:
To illustrate the standards of other countries, here are some that support at least 2 platforms:
- South Africa: Mac plus Windows
- USA: Mac plus Windows – as far as I can tell the IRS also publishes the spec so anyone can develop software for electronic filing
- UK – online filing, with options to submit information in more complex cases from other software (available from private sources, so a good guess is that the spec is available).
In summary, we are not talking about an insoluble problem. Even a developing country does better, and it’s not because Macs are much more popular in South Africa than in Australia. They represent an even smaller niche there than here.
Wednesday, 1 July 2009
It seems that polite doesn’t pay: strong words are what they are after. Could it be that the tactic many on the science side of the debate have been using of politely refuting the scientific inaccuracy of the other side is not the way to get editorial attention?
Here’s the letter and some responses to comments (since they don’t keep updating comments at the site).
DOUG Hurst (Letters, 26/6) tells us climate change isn’t always matched by changes in CO2. So what? No one claims that has to be the case except climate change deniers.
Every serious scientist working on climate science has absolutely no problem with acknowledging and taking into account a wide range of influences on climate. If Hurst wants anthropogenic carbon dioxide emissions to have been an influence on climate in the 14th century, good luck to him in finding an industrial society with the capacity to pollute on the scale that is happening today.
The argument that mainstream climate science is somehow invalidated because there is more than one driver of climate is completely bogus, and it’s time you stopped wasting space reprinting the same drivel. Repeated stating of obviously stupid arguments does not increase their plausibility.
Now my responses to comments (you’ll have to go to the Letters site to see the names):
- Perhaps rather than having written a romantic novel involving climate change, you could have written something factual – At least I know when I’m writing fiction (see sidebar, top right, for how to buy – thanks for the plug).
- The colourful climate change theories promoted by Al Gore, Tim Flannery et al are at the heart of the dire “carbon pollution” predictions that drive and apparently sustain bogus academic careers and the political positions of many ... A good number of us simply don’t enjoy being lied to and manipulated, and especially not by politicians. – What’s your evidence? I’ve put a lot of time and effort into studying the case that the science is bogus, and all of the lies and trickery are on the other side.
- Well surely then we are wasting a lot of effort on harnessing CO2 if it is not necessarily the cause? – It was not the cause of most climate variation in the past. That doesn’t mean it can’t be the cause today.
- Which is why we need more broadcasting of the deep flaws in the agw hypothesis. – Let’s hear them then. All I hear is talking points that are stupefyingly easy to shoot down.
- Thats just a bizarre statement! If there’s no link to CO2 and global warming then what the hell is the global warming industry on about with promoting a ETS? – I did not say that. I said that warming in the past was not caused by anthropogenic CO2 emissions. I did not say anthropogenic CO2 emissions are not causing warming now.
- Last time I checked the latest IPCC report these factors such as cloud albedo affect, and affect of aerosols were listed as having a low level of scientific understanding. Given this represents a high degree of uncertainty in our knowledge of the affect of these other forcing agents (of about 1.8Wm-2 or 113% of the calculation net Anthropogenic forcing)) and the low levels of warming expected from increases in CO2, arguably the precautionary principal supports a do nothing, or do very little response, until these factors are better understood – the warming since pre-industrial times is sufficient to be sure that these effects are well enough understood to have confidence in modelled predictions.
- The original theory is that emissions of man-made CO2 will cause global warming. That has not been proven. What evidence can you offer that the theory is correct? – A lot of scientific papers. But here’s one thing you can check yourself. If the sun is the sole driver of the climate then the temperature trend should closely track variations in solar output. That was true until the twentieth century when that relationship slowly changed. If you look at the last solar cycle, while it has been on a strong downward trend, temperatures have still been slowly increasing. The “paper” you point to at the Letters site claims: “If the climate feedbacks are as strongly positive as the ones programmed into the IPCC climate models...”. First, the IPCC does not do climate models; they report the work of others. Second, feedbacks are not built into these models. The feedbacks arise out of application of laws of physics and observational data. Calling people “warmists” assumes there is some sort of religion or political movement out there. There is not. There is the scientific mainstream, and there is a small group of dissenters, as in any mainstream field of science.
- Are you seriously defending Lovelock’s Revenge of Gaia’s dire predictions or saying they’re within an acceptable range of accuracy – his claims are at the outer end of probability but not impossible, especially if we do not slow down on CO2 emissions. I do not agree with him that it’s too late to stop.
- Science says that nothing happens by chance – try studying quantum physics.
- That includes the theory that greenhouse gas is the prime cause – GHG is the prime human-controlled cause. No one says the solar cycle stopped when we started burning coal. It is this kind of argument that I claim is idiotic. Go and read the scientific literature, even IPCC reports (e.g. their report on attributing climate change) if you don’t have an academic library. Over the last 10 years, the solar cycle has turned to a strong cooling trend and that has not been reflected in the temperature trend. Tell me what else could have caused that.
- Perhaps then you’d like to explain how your hypothesis fits the fact that the Late Ordovician Period was also an ice age, while at the same time CO2 concentrations at about 4400 ppm were nearly 12 times higher than they are today – No problem. First, the continental configuration was so different to today’s that you have to be careful to make comparisons (this was over 400-million years ago). Bearing that in mind, an increase of 15 times in CO2 levels is a bit less that 4 doublings, call that a 12°C increase. That increase is over whatever temperature you started with. With a large land mass over the south pole in this era, the conditions existed for a very big temperature drop as compared with today. The high CO2 level reduced that temperature drop. The sun was also weaker then. For an even more extreme case, look up literature on snowball earth. For anything vaguely comparable to what is happening today, you need to look for an era with a rapid increase in GHG levels on top of a moderate climate. Look at what happened in the boundary between the Permian and Triassic for example (251 million years ago, so we still have to be careful to extrapolate to today’s conditions).
- The ‘debate’ on AGW will continue for as long as the believers ignore the sociological and quasi-theological underpinnings of their faith – in science, we argue on verifiable facts and testable theories. If you want to call this a religion etc. you’re confused. What’s you mode of argument? Easily debunked talking points? What do you call that?
- I repeat as previous - if C02 is not the total, primary what ever cause of climate change, why are we not addressing the lot, if there is any need to do anything other trhan find alternative cleaner sources of energy – CO2 is the major human-caused effect on the climate. There is no evidence that anything else is varying the climate on a time scale that matters to human civilzation. The solar cycle is a cycle: it goes up and down. El Niña and La Niña are short-term effects.
- Does temperature control CO2 or vice versa? The Vostok ice core data shows rhythmic glacial - interglacial cycles of around 100,000 years duration over almost a million years back from the present interglacial. The IPCC proposes that the primary cyclical influence is orbital variability, which provokes temperature increase followed centuries later by CO2 increase (2007 Report, Chapter 6 page 444). The difference between the rationalists and IPCC alarmists is that IPCC concludes that CO2 then takes over as the primary forcing agent. – Drivel. The IPCC (or actually, the scientists they quote) never assume that in this scenario CO2 is the primary forcing agent. In this scenario, CO2 is a feedback. It is only a forcing if it is the initiator of the change, not a subsidiary effect. Anthropogenic CO2 is a forcing because it adds to temperature change without being caused by some other temperature change. Over geological time, there have been periods when CO2 was a forcing (e.g., when emitted as a result of plate tectonics or massive volcanoes, far bigger than any in human history).
- Peer-reviewed geological literature shows the peak of the current interglacial was around 6000 years ago with temperature around two degrees higher and sea level almost two metres higher than present. So in fact over the past 6000 years we have seen a cooling trend - But you wont read that in the IPCC reports. So much for drivel – The IPCC’s report on palaeoclimate says we are currently in period of low variability in orbital parameters, putting the onset of the next glacial at about 30,000 years. It’s not relevant whether we were or not on a cooling trend in the past. What’s your evidence that this trend is continuing?
- you basically defeat your own arguement. You argue that there are a number of other factors at play as well as CO2. This is exactly what the climate change realists have been saying for yonks – No they haven’t. The denial crew have been saying that CO2 either has no effect, or is relatively insignificant. Mainstream scientists have never said that CO2 is the only influence on the climate, only that it is the major one that humans can influence. And that there is very little chance that anything else of significance is happening on a time scale of significance to humanity.
In summary: this whole exercise illustrates what it’s all about. The denial (or inactivist) position tries to summarise climate science as alleging that CO2 is the only influence on climate, then attacks this straw target vigorously, with ever-bigger bails of straw. The fact that CO2 is not the only influence on climate is well known and well understood buy anyone who works with the science or follows it in scientific publications.
Saturday, 6 June 2009
Let’s just look at one more small sampling:
Some 85 per cent of volcanoes are unseen and unmeasured yet these heat the oceans and add monstrous amounts of CO2 to the oceans. Why have these been ignored? Why have there been five significant ice ages when CO2 was higher than now? Why were warmings in Minoan, Roman and medieval times natural, yet a smaller warming at the end of the 20th century was due to human activities? If climate changed at the end of the Little Ice Age (c.1850), is it unusual for warming to follow?
Computer models using the past 150 years of measurements have been used to predict climate for the next few centuries. Why have these models not been run backwards to validate known climate changes?
I would bet the farm that by running these models backwards, El Nino events and volcanoes such as Krakatoa (1883, 535), Rabaul (536) and Tambora (1815) could not be validated.
Let’s take his assertions one at a time.
- 85 per cent of volcanoes are unseen and unmeasured – so what? If this effect is not changing it is not part of any increase in atmospheric CO2. There are massive fluxes in CO2 between the atmosphere and the rest of the environment all the time. These fluxes at a period of stable climate are in balance. By adding an additional flux, we are pushing the climate to a new equilibrium state.
- Why have there been five significant ice ages when CO2 was higher than now? – possibly because the other factors driving the climate at the time were different? How about checking paleoclimate research to investigate this question? The effect of a given level of CO2 or other greenhouse gases on the climate has to be measured against other influences. No one claims CO2 is the only influence on climate – except psueudo-sceptics like Plimer.
- Why were warmings in Minoan, Roman and medieval times natural, yet a smaller warming at the end of the 20th century was due to human activities? – the claim that these earlier warmings were greater than current warming is controversial but leave that aside because it’s irrelevant. What is relevant is whether something different is causing the warming now and whether that different thing is an ongoing effect that could result in a higher, dangerous level of warming. The other warmings were clearly not caused by anthropogenic greenhouse gas emissions because industry did not exist at those times on a scale that could have caused them. Any natural causes such as increased solar activity does not apply today. Continued CO2 emissions will not stop of their own accord. This argument only makes sense (assuming he is right about the scale of previous warmings and that is doubtful) if Plimer is able to argue that CO2-based warming will somehow be limited.
- If climate changed at the end of the Little Ice Age (c.1850), is it unusual for warming to follow? – so what? No one is arguing that there is no natural climate variation.
- Why have these models not been run backwards to validate known climate changes? They have. To assert otherwise is ignorant or dishonest.
- I would bet the farm that by running these models backwards, El Nino events and volcanoes such as (1883, 535), Rabaul (536) and Tambora (1815) could not be validated – what is he asking here? Does he want climate models to predict when volcanoes will happen and how large they are? It has been millions of years since a volcano big enough to cause more than a minor climate shift has happened. Krakatoa had an affect that is still measurable today but not so big as to cause problems with the general trend of climate models.
Overall, the points he raises are insubstantial and have no real bearing on the problem of anthropogenic climate change. If he has evidence to overturn this judgment, he should publish in the academic literature. Otherwise his claims are vacuous, just so much hot air.
Sunday, 19 April 2009
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.
Monday, 30 March 2009
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.
Friday, 9 January 2009
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.
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.
Also published at Online Opinion.