The precautionary principle is something that often lies at the heart of the environmental debate. It basically works on the principle that if a particular activity or policy carries a suspected risk of some sorts, even if that risk is not fully proven (i.e there is a scientific consensuses) then the burden of proof lies with the supporters of said action or policy to prove its safe, rather than it be proved as being dangerous. It is somewhat similar to the medical tradition of “first do no harm”.
However it is also an often misunderstood concept that has been used misused and abused to justify everything from ridiculous health and safety rules to extraordinary rendition during the war on terror.
But where did it come from? It is often mistakenly assumed that it came from the environmental movement, or the world of medicine. Actually one of the originators of the precautionary principle was the pioneering Engineers of the Industrial revolution. To understand how the precautionary principle is meant to be applied it is worth investigating its origins in engineering.
The Age of Steam, Iron and accidents
From the 1800’s onwards the world entered into an era called “the industrial revolution” when a variety of key technologies reached a critical mass sufficient to herald in what we now called “the modern world”. Engineers were key to this development and the early days of the Industrial revolution was very much a golden age of engineering. Taking advantage of new materials, such as mass produced steel and cast iron as well as engineering techniques such as lattice structures or thermodynamics (central to the functioning of the steam engine) engineering had entered into a golden age when many extra ordinary structures were built, from the Bristol to London railway, the Brooklyn Bridge, the Great Western, the Bell Rock lighthouse or the Eiffel tower.
The Great Eastern under construction
But in the process of pushing forward engineers frequently found themselves working at the very edge of what was technically possible. Worse still given the science at the time (atomic theory was in its infancy, microscopes were still of limited use) in many case the engineers didn’t know where exactly the edge was! There were significant grey areas and thus frequently engineers found themselves, as it were, flying blind. Inevitably this also made the industrial revolution the era of spectacular failures, most notably the Tay Bridge disaster, the Versailles train crash or the Boston Molasses tank failure and disaster.
For example, the root cause of the Tay Bridge was a failure to understand the effects of wind loading, poor material fabrication (unsurprising given the large volume of iron cast in a remote area by inexperienced people) as well as fracture mechanics. Another two bugbears of era was the phenomenon of thermal creep and fatigue (a factor in many other disasters, including the latter two above) – the name of the last of these “fatigue” should give you some clue as to just how much in the dark engineers were as to the root cause of these problems. In the case of “fatigue” failure it left these strange intergranular cracks that looked to engineers like the metal just suddenly got “tired” and gave up!
An example of a metal fatique failure, from here
Given the limits of material science at the time engineers were frequently forced to rely on their intuition and learn as much as possible from past mistakes. In the case of fatigue it was frequently noted that such cracks seemed to originate at a badly finished surface, or at some form of “stress concentration” (such as a hole). Parts that had undergone some form of cyclic loads (a load that is applied and then released in rapid succession, think of a small child bouncing up and down on a trampoline) tended to be more vulnerable to fatigue that parts subjected to much higher, but more constant loads (think of a large man lying in a hammock!). While engineers still didn’t fully understand what was driving this “fatigue” phenomenon, the above information provided a prescription for avoiding fatigue failures. Try to avoid where possible applying cyclic loads. If you can’t avoid this, as would often be the case with machinery, at least make sure the point of maximum stress is free of any stress concentrations. Also ensure that all parts of a mechanism are machined to supply a smooth surface finish, especially near any stress concentrations. Finally, regularly inspect any parts where fatigue could be a problem. Better yet, scrap and replace them at regular intervals.
The above example of how Victorian engineers dealt with fatigue gives you an idea of how the precautionary principle came into being. Engineers knew something dangerous was going on, but they couldn’t absolutely prove it. Thus they opted for a design that was less likely to fail catastrophically. They also adopted a policy of critiquing one another’s work. Brunel would frequently find himself examining the work of Stevenson and visa versa. Generally if during one of these visits the presiding engineer presented a plausible hypothesis for how a potentially catastrophic failure could occur, the onus would be on his colleagues to prove him wrong, rather than the other way around.
The Forth Bridges, a case study in over-design
Forth Bridges, modern road bridge in the foreground and the Victorian railway bridge in the background
In Queensferry Scotland (just outside of Edinburgh) two vast bridges stand side by side, a Victorian era cantilevered railway bridge and a modern suspension bridge. One would be forgiven for wondering, looking at the thick steel beams of the rail bridge and the thin wispy cables of the road bridge, that one of these two must have been over-designed or else its neighbour was under-designed. Actually it’s a bit of both. The Rail Bridge was built in the wake of the aforementioned Tay Bridge disaster. This saw the engineering pendulum swing from one extreme (a dangerously under-designed bridge) to the other extreme (a highly cautious design). The result has been a bridge that, some 120 years later is still in service, with 180-200 major train movements per week. The road bridge incidentally has come down with a corrosion related defect and will likely shortly be out of service, thus the Victorian era bridge will see its modern neighbour come and go – they just don’t build them like they used too!
Of course the pessimist would say, well maybe we should build all bridges like the Forth railway bridge. Indeed this approach would certainly reduce the risk of bridge failures to an extremely low level. However, it would also ignore the 57 men who died building the Forth railway bridge, as inevitably such a large structure is difficult to build. And more costly too, both in terms of initial construction costs and higher maintenance. While the expression “painting the forth road bridge” is something of a misnomer, it is certainly true that the maintenance costs of such a structure are a lot higher than those of a more simply designed structure.
The price of doing nothing – Every decision has a price
This is one of the major issues with the precautionary principle, every decision has a price. Going for a beefier bigger bridge results in a lower risk of it failing, but involves a higher risk of people being killed building it or maintaining it, not to mention the higher capital costs, which means less bridges, and how risky is it to cross a river other than via a bridge?
Let us take another engineering example, the humble air-bag. Invented in the 1970’s air-bags are one of a number of innovations that have revolutionised car safety in the last few decades. Countless thousands of lives have been saved by airbags, not to mention many serious injuries prevented, such that many people have simply walked away from accidents that would otherwise have likely been a crippling or lethal (see Ian M. Banks experience here).
But airbags can also kill. Not long after the introduction of airbags, reports started to filter back to the auto engineers regarding serious injuries to “improperly restrained” (read not wear a seat belt) individuals in low velocity accidents (that otherwise would have not resulted in serious injury) and worse still of young children being killed, in particular those in forward facing child safety seats. The engineers were forced into a dilemma. Scrap or suspend use of air bags (and begin an expensive product recall of cars to disable them) knowing full well this would lead to many deaths of people who would otherwise be saved by airbags, or do nothing, at least until they had more data, even though they knew these would lead to further injuries and deaths also, thought likely on a much smaller scale. In the end they choose the latter option, which with the benefit of hindsight was the right call. Warning signs were placed in cars reminding people to wear their safety belts at all times and not to drive with young children in the front (modern cars now generally have a switch which allows the passenger airbag to be enabled or disabled).
This example demonstrates that when using the precautionary principle we are frequently left with choosing the least worse option. It is rare you wind up with a choice between a perfectly safety course of action and a sure road to disaster. Furthermore, we need to base any decision on firm facts. In the case of these airbag related injuries that meant incident reports from the NTSB and crash test experiments in labs, rather than scary tabloid headlines or hearsay. Incidentally, should anyone wonder how such a glaringly obvious oversight such as the risk of airbags to children have been overlooked, the advice at the time to parents (and indeed it still is to this day) was to always put children in the back (safety seat restrained or seat belted) as here they would be safer and less likely to distract the driver. Of course, such sensible advice ignored human nature, that if a parent was with a child alone in the car, particularly a young child, she’d likely want the kid next to her. Worse still those very individuals were types who would be most likely to buy rearwards facing seats (so they could maintain eye contact with baby while driving). This of course demonstrates another factor – the X-factor. How human nature, or the natural forces, may see systems or machines used in ways that the engineers in the lab may never have envisaged.
Fiddling while Rome burns
Of course there is a fine line between safest course of action? do nothing until we have reliable data and fiddling while Rome burns. Waiting until you can prove the case firmly either way may mean waiting too long – or mean waiting until your “theory” is confirmed by large numbers of body bags! An excellent case study of this dilemma comes from the Space Shuttle Challenger disaster.
On January 28 1986, 73 seconds into its 11 space flight, space shuttle Challenger was destroyed in a spectacular fireball, live on national TV. All seven of her crew were killed, including most famously “teacher in space” candidate Christa McAuliffe. I would incidentally note that contrary to what the anti-hydrogen economy lot would tell you its likely the crew survived the “explosion” (strictly speaking there wasn’t actually any explosion anyway), but were likely either killed by asphyxiation or on impact with the sea 2 minutes and 45 seconds after the explosion.
How could such a terrible disaster happen? Worse, it eventually became clear that the failure of Challenger had been predicted in advance by engineers working for Morton Thoikol (now ATK) who built the critical Solid Rocket Boosters (SRB’s) for the Shuttle. At fault it seemed were the SRB “o-rings”. Because Morton Thoikol were based in Utah and the shuttle was launched from Florida, it was necessary to transport the SRB’s by railcar to the launch site. To allow for this, the SRB’s were made in sections, with each section being sealed against the next by a pair of large washers – the O-rings.
O-ring failure sequence, from “The State” newspaper
As early as 1981 evidence began to emerge of damage to the O-rings during certain flights, as a result of so called “blow by” from superheated gases escaping through the O-rings…while in other flights no damage was observed. Central to such investigations was the Morton Thiokol engineer Roger Boisjoly. He and his colleagues had a theory that O-ring damage was being caused by them becoming hard and less effective at low temperatures. He and his “seal taskforce” were, at the time of Challenger trying to gain evidence to support this low temperature theory. Worse, an earlier mission in January 1985 had resulted in significant damage to the primary O-ring and some to the secondary O-ring. However, the task was being complicated by an incomplete understanding of exactly how this blow-by damage was being caused. The erosion models they had developed suggested that the O-rings should still hold (of course the observed damage suggested there was something seriously wrong with the model!). Also just to complicate things, a subsequent launch of the shuttle in October had also resulted in O-ring damage, yet during this launch low temperatures had not been an issue.
On January 27th Challenger scheduled launch was again scrubbed as a result of bad weather (and a number of technical problems). Delaying the launch till the following morning would mean the shuttle being left on the pad while exposed to freezing temperatures (yes it does get that cold sometimes in Florida!). So cold indeed that ice began to form on the pad. That night, with temperatures well below -8 °C the ground crew would use some 14,000 gallons of anti-freeze defrosting the shuttle and pad.
Needless to say when Boisjoly and his team heard of this, they immediately jumped into action in an effort to stop the launch. They’re decision tree was, while we can’t prove low temperatures are a risk to the shuttle, we can’t prove that it is not a risk. The consequences of launching now are thus a credible risk of catastrophic failure so we shouldn’t launch (the propulsion engineers at Thoikol had apparently told the sealing taskforce engineers that if both O-rings failed, the shuttle would likely be destroyed on the pad, with the explosive force of a small nuclear bomb! although such fears proved unfounded). Thus the precautionary principle said, the launch should be suspended until temperatures were higher or they could give a definitive answer either way as regards the low temperature effectiveness of the O-rings.
“Go away and don’t bother us with the facts.”
Should you be wondering why Challenger did launch if the engineers were this concerned it would fail, well this introduces another curve ball into the whole precautionary principle debate – politics and money.
NASA were under huge political pressure to get the shuttle off on the 28th (otherwise Christa would be giving her teacher in space lessons to empty class rooms over a weekend) as well as maintain their ambitious schedule of shuttle launches. Also, by constantly delaying the shuttle (it had been held up for several days now) this was not a risk free decision. There was the risk that a further delay would mean missing a safe launch window on the 28th and instead forcing a launch later on a day with riskier weather conditions. http://en.wikipedia.org/wiki/Space_Shuttle_Challenger_launch_decision
Morton Thoikol management were also under pressure and fearful of loosing the SRB contract. An infamous teleconference on the night of the 28th crystallises this all too frequent dilemma. Roger Boisjoly and his team presented their low temperature theory. NASA managers and engineers weighted in with their criticism of this hypothesis (the focus of which was the discrepancy between erosion model and data as well as the October 1985 launch with O-ring damage) not to mention indignation that such an issue hadn’t been raised before – as one of the NASA controllers put it “…you’re generating new launch commit criteria! When do you want me to launch? Next April?”
Eventually after much arguing it boiled down to a management decision in which the Morton Thoikol managers all voted to overrule they’re own engineering team and recommend a launch. As Boisjoly described it, the attitude of management could be described as “Go away and don’t bother us with the facts.”
When one of the managers, who was a trained engineer (and thus his engineering instincts were to recommend a launch hold) showed signs of wavering one of the other managers told him to“take off his engineers hat and put on his management cap”. The rest is history.
The Challenger disaster is an important lesson in the precautionary principle. Clearly when you have evidence, even if it’s incomplete, of a potential catastrophe, one should always choose the safer option. Also managers and politicians need to realise that there’s not much point hiring engineers or scientists to give you our professional opinion if you’re planning on ignoring it! Such a policy amounts to betting that the experts are wrong and your instincts (clouded likely by a desire to make more money) are right.
A similar situation to Challenger occurred with the 2000 Ford Explorer roll over controversy or indeed the Ford Pinto case or the Ladbroke Grove Rail crash. In all these cases management “bet” against their own engineers being right and the opposite proved to be the case!
Incidentally, another critical lesson of Challenger regards backups. A large part of the decision to launch was based on the knowledge that there were two O-rings, so if one did in fact fail, surely the other one will do the job in its place. Such faulty logic ignores the gold rule of any backup system – Never rely on backups! As soon as you start to rely on backup systems it ceases to be a “backup” and gets upgraded to a mission critical “primary system”. This undermines the entire principle of backup’s and defence in depth.
Liquids on a Plane
In the Challenger disaster the powers that be failed to act on the available evidence and prevent a disaster, as they felt the evidence was not sufficiently strong to warrant such an action. But in a number of cases they can do the complete opposite, over-react to risk.
A good example of this has been the conduct of the war on terror. While acknowledging that there are indeed some small numbers of terrorists intend on committing mass murder and mayhem, this risk has to be put in the proper context. The number of such individuals is extremely small and their technical proficiency is general both poor, as recent incidents have shown. There is little evidence to support the theory that Al-Qaeda is some sort of vast web of terrorist networks worldwide, as discussed by Adam Curtis in his documentary “the power of nightmares” (also it can be viewed here). The reality seems to be a small handful of wanabe jihadi’s (who do not represent the majority views of the Muslim people) whose skill and training as regards bomb making or organising terror attacks one could best describe as “amateurish”.
The two main weapons it is feared they will yield, a dirty bomb or a liquid bomb, there is again little evidence if any evidence to support these theories. Indeed one or two academic papers (Reshetin (2005) and Dingle (2005)) have suggested that the likely fall out from a “dirty bomb” was unlikely to be serious, as it was difficult conclude it would be any more deadly than a conventional car bombing, although the cleanup costs would inevitably be higher. The viability of a liquid bomb has also been questioned (although they engage in some degree of hyperbole the following news story gives you a feel for the situation).
And we must balance the risk of terrorism against a host of other real risks we take each day, the table below should give you a flavour for the risks anyone in a western society takes pretty much on a daily basis:The above numbers are a little out of date, as they come (except the last 4) from a 1980’s US gov bureau of statistics study, but they give you a flavour for how things lie. With terrorism, I added up all the deaths to civilians in the western world since 10/09/01. This gives us a total “body count” of 3,291 including 9/11 and 318 excluding it. A population of 500 million in the EU and 340 million in North American => (500m+340m)x9yrs/death rate
As we can see the risk of being a fatality from terrorism is extremely remote, at least compared to a host of other risks we accept on a daily basis. If we regard terrorism as such an enormous and unacceptable risk, then surely we should take action on some other of the headline figures above first. All private motor vehicles should be banned and the presenters of Top Gear sent to Gunatanamo Bay (I’m quite sure they’d be okay at being waterboarded so long as it was with petrol!). We should ban cigarette smoking also (that 1: 720 figure is a general population number (per yr!), a regular smoker would have a vastly higher chance of contracting cancer and dying from it). All privately held firearms in the US should also be banned and we should consider shutting down some of our older nuclear reactor fleet (the low figure above comes from the WASH-1400 report and represents the worst case scenario for certain older PWR type reactors…or indeed probably a best case scenario for RMBK’s! the high case is a widely quoted figure for more modern Gen III+ reactors, in both cases note it’s the risk of core meltdown and not fatalities).
Take these new airport scanners that they have introduced (so called Smut machines) that can peer inside your clothes. Aside from the ethical and human rights issue we have to consider the cancer/radiation risks associated with them, again no decision is ultimately risk free. Using these machines involves exposing people to low doses of radiation, which may be harmful to their health: . Given the shear volume of people involved, around 700 million air passengers last year in the US alone, given that these scanning machines are being operated by amateurs (unlike the individuals operating similar machines in hospitals who’ll generally have at least a degree level education in radiography) and given that a good proportion of regular air travellers and air crew will be exposed to these radiation doses on a fairly regular basis (and both groups already have a heightened radiation risk due to frequent travel at altitude and thus higher exposure to cosmic radiation) there is a risk these machines might wind up killing more people than they save.
Now if we were catching terrorists every week at airports, then maybe there’d be a point to this, but we’re not. Indeed I can’t think of a confirmed case where terrorists have been actually caught by airport scanners in any Western country. We also have to consider the financial costs of such systems, the precautionary principle is not an excuse to write a blank cheque. Of course the authorities will say that these measures “deter” terrorists, but proving that is very difficult to quantify, and again the precautionary principle requires evidence to support any action, its not an excuse to run around like a headless chicken.
Finally, there are far greater hazards to an aircraft than terrorists, you will note the figure above for simple “air accidents” is many times higher than the risk of terrorism. There are many causes of air accidents, from mechanical failure to human error, but often it’s a combination of several factors. One unfortunately common trend is a correlation between delays to a flight and “things going wrong” with that flight (staff in a rush getting flustered and missing something), hence why airlines like to stick rigorously to a routine. Those things “going wrong” ranging from lost baggage (airline ever loose your bag? I bet the flight was delayed or held up in some way) to some major disaster (this is why the flight attendants are so angry with you for being tardy).
Given that these new security procedures will inevitably increase the incidents of such flight delays one has to weight up the improved security with the risk of further accidents. Casing point, the worst air accident in history occurred in Tenerife in 1977 when two fully fuelled 747’s collided on runway. While there were a host of causes of this accident, pilots under pressure and forced to rush, communication difficulties, heavy fog, etc., the ultimate trigger for the accident was the over-reaction of ground staff at La Palma airport to a minor terrorist incident.
I would note for anyone whom I’m putting off flying, again look at the numbers above, air travel is about 30 times safer than car travel. You are much more likely to be killed in the car journey to/from the airport than in a plane crash and you’re more likely to be struck by lightening that to be killed by a terrorist!
Thus the point is that the precautionary principle is not an excuse to run around in circles screaming that the sky is falling. One must balance any risk factors against one another and as noted, no decision is ultimately risk free, and there are the costs to consider. Of course, I finally would note that in all probability the real reason for the excessive security measures taken as a result of the “war on terror” has likely little to do with saving lives but saving the careers of certain politicians. I refer to this as Save Ass Policy Scheme….or SAPS for short.
Another excellent example of SAPS in use is the various pronouncements from those high-visibility jacket wearing Health and Safety types. They’ve attempted to ban practically anything that one could remotely consider risky, from preventing kids playing with conkers, or indeed playing in the school yard at break times at all. There also been a crack down on PE lessons in some schools due to the “risks” involved. Other examples of this lunacy include an attempt to ban a cake sale (due to the risk of bees being attracted and stinging someone with an allergy or someone with a nut allergy buying a pecan pie), banned council gardeners from wearing shorts (on grounds that they might get nettle stings), and my personal favourite, they’re now requiring that the upstairs of many Bothies (remote mountain shelters in the highlands of Scotland) being closed off (least someone slip on the stairs!).
All of the above example are justified under the heading of “Precautionary Principle” but the reality is it’s more a case of SAPS instead. To take the child’s play issue, for example, kids learn a good deal of their social interaction skills from playing as well as their ability to accurately assess risks (when I was a kid climbing trees and falling out of them was how I learnt not to do silly things!). The danger is we’ll breed a next generation of people who will lack effective social skills and be far either too risk averse or take dangerous unacceptable risks. Then there’s the issue of childhood obesity, which is in part caused by a lack of exercise among kids, something that dramatically shortens ones lifespan. Again there is no such thing as a risk free decision.
In the case for example of the closing off of bothies, this ignores the risks people endure trying to get to these places (which usually involves climbing over mountains….I think I can manage a stairs after that!). By reducing the holding capacity of these bothies, you greatly increase the risk of someone getting caught out in a blizzard or severe weather event, which I would argue is a much more pressing risk to any mountaineer than falling down some stairs or a lack of fire exits!
All of these policies have, as noted, actually got very little to do with either the Precautionary Principle or Health and Safety. A policy of Liability Avoidance or again the SAPS running various organisations would be accurate reasons. But it’s important we say so rather than blaming it on Health and Safety. And the key point again is that the precautionary principle is not an excuse to run around like a headless chicken little, far from it! I would question again whether some of the above noted policies actually improve “safety” or in fact actually endanger it.
A case study in the Precautionary principle – Climate Change
A good example of where the above points merge is the issue of climate change. I’ll assume that everyone reading this has not been living on Mars the last few years and is vaguely familiar with the arguments for/against Anthropogenic climate change. If you’re not familiar with the arguments, then this link to wikipedia and this one to the Beeb’s are good places to start. Some more detailed and balanced information can be found on the Realclimate website here.
Anyway, the fears of the IPCC are that the buildup of greenhouse gases in the atmosphere is gradually heating up the planet. Carbon dioxide from the burning of fossil fuels is believed to be one of the primary, thought certainly not the only, cause of this phenomenon. Since the beginning of the industrial revolution CO2 levels have increased from 280 – 388 ppm (a 39% increase), with methane levels up 149% and nitrous oxide levels up 16%. This is believed to be the primary cause of recent warming and is consistent with Fouriers 1820’s “greenhouse effect” theory and Svante Arrhenius 1896 hypothesis that the increasing concentrations of greenhouse gases from industry could lead to the planet heating up. You will note the age of both of these two theories, this should demonstrate that we are not dealing with some vague newly developed concept (as some sceptics will try and paint it) but established scientific theories that are a good century old.
So what is the likely outcome if we continue as we are doing? Well the IPCC reckons the world may warm by between 1.1 to 6.4 ‘C average temperature rise within this century . That might not sound like much, until you realise that the Paleocene-Eocene thermal maximum (a minor extinction level event that occurred 55 million years ago) only involved a 6 ‘C rise over 20,000 years! The worst case scenario from the IPCC is actually many times steeper than this! But even that 1.1 ‘C is cause for concern, remember this is average global temperature that we are talking about. Some parts of the world, particularly towards the poles will heat up much more, the daily temperature swings worldwide will be much more pronounced. More extreme weather or shifts in weather patterns are a possibility.
It should be noted that a climate zone can move up to several hundred km’s north or south in the event of a mere 1 ‘C change in temperature. Given that some parts of the world, notably the mid-west of the United states, parts of the Mediterranean and India occupy a precariously balanced climate zone, it would only take a relatively modest warming scenario to essentially dry these areas out and turn them into shrub land or desert, indeed much of America’s wheat fields and prairies were desert the last time the world was 2 ‘C warmer. Of course, the climate zone will move not disappear, so great news for Canadians and Scandinavians…course insects species, diseases and other pests will move with the climate zone! And it will be cold comfort for the many impoverished Indian and Texan farmers! There are also other concerns regarding climate, for example that as noted extreme weather events such as hurricanes and flooding will become more severe. http://en.wikipedia.org/wiki/Effects_of_global_warming
Then there’s the fear that the Gulf stream may shut off, although the evidence to support this theory is currently somewhat sparse. Even so it is perhaps an example of the X-factor related to rapid climate change, we simply don’t know the consequences of a such an event as it has never been witnessed in recorded human history so the effects both positive and negative are difficult to quantify.
But what do the sceptics say? It should be no surprise that there are some sceptics of a theory such as global warming, every scientific theory no matter how well supported or accepted has always had its critics and doubters. Einstein wasn’t too keen on Quantum mechanics, the very term “Big Bang” was invented by the Astronomer Fred Hoyle as a means of ridiculing the idea as he was a firm supporter of the alternative “steady state” model. Of course it has to be said that some of the critics of climate change theory have something of a dubious reputation notably that some are being funded by the fossil fuel lobby. But even dismissing such factors, it has to be said that most of their criticism, a good critique of them can be found here on Realclimate and the New Scientist has a pop at a few of the more common climate change myths here, could be described as little more than nitpicking.
One of the critical points the sceptics seem to be missing regarding the Precautionary principle is that it is the job of the sceptics to prove the theory of Anthropogenic climate change wrong, not the IPCC’s job to prove it right. I have yet to see anything coming out of the sceptics that has even come close to doing this. Notably they would need to find some scientific explanation for all the evidence showing warming, find and then prove an alternative source of warming (if they can’t do the last one) and finally overturn the 150 year old principle regarding the high absorption co-efficient of carbon dioxide towards infrared radiation, something that John Tydnall once discovered and something that has been repeatedly proven since (i.e. they would need to basically overturn much of our present understanding of basic chemistry and climatology!). In the absence of such information the precautionary principle says we must assume that the IPCC is right and act accordingly.
But what are the chances that the IPCC are right? The Precautionary principle requires we assign some level of probability to this discussion. They reckon that there is a mere 5% chance that the observed warming is due to natural factors, i.e they are 95% certain that they are right. Even the sceptics seem to agree there is some risk that they are wrong and the IPCC is correct. I seem to recall John Christy, one of the few sceptics with a relevant academic qualification suggesting in a TV interview (see the video in the link) that he accepts most of the core theory (i.e CO2 is a greenhouse gas, most of the increased amounts of this in the atmosphere are from industry and that the world is warming up), his principle disagreement regards how much of that warming is caused by us and the “uncertainty” within the IPCC’s model. He implies a 50-25% window of probability. So that means there’s, according to a climate skeptic, a 1:2 to 1:4 chance of a warming event occurring, while the IPCC reckons its more like 1:0.95. You will note that even the largest of these probabilities, 1:4 is substantially higher than any of the risk factors we discussed earlier. Even if we assume an absurdly low fatality risk factor of 1:200 per year (i.e. 1:8,000 per lifetime), that brings us to 1:800 or 1:190 (IPCC figures) which makes climate change an equivalent fatality risk as cancer! Indeed its again curious that the many right wing supporters of strong anti-terrorist legislation can get so worked up about something that has a probability factor in the millions to one against, but don’t want to do anything about something that’s in the single figures to one against!
But every decision has a price, what is the price of taking action on climate change? Given that the bulk of climate change is currently being driven by greenhouse gas emissions, the most effective way of preventing dangerous climate change would be to cut back on, or clean up, our fossil fuel use. This could have significantly negative economic effects, and a slow down in global development. However, we must balance this against the economic growth generated by increased production of renewable systems. Also we’re assuming we can continue to use fossil fuels indefinitely, which we can’t, they are a finite resource. Indeed there are some proponents of peak oil theory who say we have either passed the peak or are approaching the peak in oil production. And of course carbon dioxide is but one of the many “nasties” that come out of factory chimney’s and tailpipes. There’s all sorts of other ecological and health related effects that continued fossil fuel use enforces on us (the WHO reckons 2.5 million direct and indirect air pollution deaths per year), nevermind the political effects (see Iraq war!).
So all in all, the case that climate change is a threat that should be taken seriously is difficult to refute. The climate sceptics have to date failed to comprehensibly rebut the theory of Anthropogenic climate change, so the Precautionary principle says that it must be taken seriously (Fail safe). The probability of dangerous climate change occurring is uncomfortably high. Finally while the act of mitigating away from fossil fuels will be economically painful we have a multitude of reasons other good reasons to do so irrespective of climate change, not least of those being the fact that we’ll have to give up fossil fuels anyway some day, so we may as well do it now while we have an electricity grid that runs 24/7 and a stable climate.
And I stress the above should apply regardless of whether you “believe” the IPCC or not. If you still feel that climate change is an acceptable risk then my advice would be to cancel all you’re insurance policy’s cease to worry about terrorism. If you’re American sell your guns (the probability of being forced to use a gun in self defence are vastly lower than the risk of climate change) cancel you’re health care plan and cease to do silly socialist things like wearing seatbelts and looking both ways before crossing the road.