Y Safle

The BBC carries details of a report on the possible effects of climate change. Predictions, of course, are hard (especially about the future)! But after a great deal of debate, some conclusions have been drawn - one of which is not entirely surprising: the people most at risk from climate change are the world’s poor - those least able to avoid its effects.

According to the BBC:

The impact of climate change has been a major source of dispute Billions of people face shortages of food and water and increased risk of flooding, experts at a major climate change conference have warned. The bleak conclusion came ahead of the publication of a key report by hundreds of international environmental experts.

Agreement on the final wording of the report was reached after a marathon debate through the night in Brussels.

People living in poverty would be worst affected by the effects of climate change, the gathered experts said.

“It’s the poorest of the poor in the world, and this includes poor people even in prosperous societies, who are going to be the worst hit,” said Rajendra Pachauri, chairman of the Intergovernmental Panel on Climate Change (IPCC).

http://news.bbc.co.uk/1/hi/sci/tech/6532323.stm

The report may be downloaded in PDF format.

Global Temperature Anomalies. Photo: yeimayaDiscussion of climate change can seem so academic at times, and I wanted to make it a little more family friendly. Thus I was pleased when a commentator on this blog (Jason) wrote regarding global warming:

OK, this is the theory [referring to role of greenhouse gases in warming our climate, and the means by which they do this. Carbon dioxide included.] I thought you meant. I agree with the physics behind this theory, and consequently believe that it is true. (except for the part about positive feedbacks exceeding negative feedbacks, The models clearly assume substantial positive feedbacks, and I don’t think that the data supports this at all. But a model is just a model. Either it will prove right or it won’t. I can wait for experimental validation.)

But you said that this theory had been experimentally validated. I am not aware of any such validation and am fishing for a reference.

Swindled by Global Warming Sceptics

Jason claims he agrees with the physics, and yet he still wants to know about the experimental validation. I suppose this means that the theory is plausible to him, but he is not aware of experimental validation of the greenhouse effect (outside of the data from climatologists of course - but our warming our atmosphere is not a controlled experiment).

But rather than dredge up more scientific references, I thought we could add some fun to this question, and perform our own experiment. So here are instructions to build your own global warming experiment using CO2 and water vapour. Note that we could extend this to methane too, but the collection of household methane is usually a smelly process, best left to the more intrepid amateur scientist.

Equipment

• Two 2 litre plastic drink bottles
• Two thermometers (preferably digital ones)
• A drill bit to drill a hole large enough for the thermometer (if you have a large rectangular digital thermometer, you will need to improvise a bit!)
• Two clamp stands and clamps (or some ad hoc support!)
• Carbon Dioxide. (For me, the best way to get CO2 is from a Soda Stream, although there are other ways, using bicarbonate of soda for instance).
• Two desk lamps (don’t use energy saving bulbs - 60W or better incandescent bulbs are required)
• Plasticine (That staple of home physics experiments!)

Method

Remove the labels from the drinks bottles and drill holes in the tops large enough to allow the thermometers in. Set up the clamp stands close to the lamps. Make sure that the bottles will not be so close to the lamp that they will melt. Also be very careful about placement. The stands (and the bottles) must be placed identically for the two bottles - the same distance away, and keep the desk lamps at the same angle and the same height. Keep the lamps turned off for now.

Fill one of the bottles with carbon dioxide from your soda stream! screw the top on tight and plug any gaps with the plasticine. The other bottle should also be sealed with plasticine (but don’t fill it with anything. You just want the ordinary atmospheric air that is already in there).

Now check the temperature in the bottles. The carbon dioxide bottle may be cooler as it was filled from a canister of compressed gas. Wait until the temperatures equalise, and when they do so, switch on the lamps, note the temperature and time.

Over the next half hour, monitor temperature and time regularly (at least 5 minute intervals).

Expected Results

Over the course of the experiment, the temperature in the bottle filled with CO2 should rise higher than the bottle filled with just plain old air. For extra credit you could try altering the concentration of CO2 in the bottle to see how the concentration affects the results (rather hard to do scientifically with this equipment, but give it a go!)

Water Vapour

Water vapour is another greenhouse gas. You can repeat this experiment for water vapour. Instead of filling the bottle with CO2, fill it with water vapour. First make sure the other bottle is filled with air in a cool dry place. Next take the bottle to be filled with water vapour to the bathroom. Have a hot steamy bath. Take your bottle with you and during your bath, seal it as before.

Note that it is quicker to fill the bottle from a steaming kettle, but you will almost certainly scald your fingers, and much of the vapour will just condense in the bottle. Better off with the bath methodology.

Now repeat the experiment. If your atmosphere was quite humid when you performed this experiment you may not see much difference - try leaving the ordinary atmosphere bottle in the fridge for 10 minutes, then seal it quickly before removing it. Allow it to return to room temperature and repeat (this will reduce the water vapour in the bottle because cold air holds less water).

Most of all - have fun. This experiment is best performed with the help of young children. No animals were harmed in the making of this experiment.

Someone wrote to me regarding the amount of carbon dioxide we are producing, saying:

It is your opinion that the amount of carbon dioxide being put in the atmosphere is not puny, it is not an established fact.

We know what we are pumping into the atmosphere. We know that we have increased CO₂ levels in the atmosphere by more than a third since the 19th century. This is not my definition of puny.

Human emissions are dwarfed by the emissions of termites.

I am unconvinced by this claim. I have seen no sources, and it seems highly unlikely to be correct. However, the fact that the natural carbon cycle pushes CO₂ into the atmosphere in vast quantities is irrelevant, because it is only an issue if you are relying upon vegetation to act as a permanent carbon sink - which it will not. What termites do, and have always done, remains in perfect balance: A termite cannot produce CO₂ if it does not eat. Termites eat wood - not fossil fuels - so the carbon dioxide they release into the atmosphere has been locked up in wood for at most a hundred years or so. They are part of the natural balance

Burning fossil fuels releases carbon locked up for millions of years. This is additional carbon dioxide to that produced each year by termites and other living creatures. Unlike the activities of living things, this burning of fossil fuels is not in balance - and growing forests will not solve the problem, because of those pesky termites.

Consider it another way. Let us suppose you have a houeshold budget. Each year you receive an income, which consists of salary and dividends on investments. Your outgoings each year go on cost of living and a small amount of investment.

Now if our outgoings are no larger than our income, then everything is just fine. Indeed, your investment will grow slowly.

But now consider what would happen if you increased your cost of living, by purchasing bigger cars, private jets and so forth. Suppose that your cost of living alone now exceeded your income by half as much again. How would you finance this?

Instead of growing investments slowly, you would eat rapidly into your capital.

And if your capital is not very large, then before you know it, you will have no capital left, and be worse off than when you began - because you now have no dividend income either!

This is the way it is with the carbon budget. Until now, the carbon cycle has recycled nearly all carbon back into the atmosphere, helped by termites and other living creatures - including us! But the budget has been balanced, and little by little, carbon has been tucked away.

But for the last century we have been squandering that capital, and pushing carbon back into the atmosphere beyond the means of the earth to cope with the increase.

Blaming termites and flatulent cows (or even breathing humans) is the straw man. It is our eating into the carbon capital that is the problem - not the natural process of the carbon cycle.

Not enough is known about the effects of adding CO₂ to the atmosphere to say for certain that burning fossil fuels leads to any problem at all.

Enough is known to say that it is very likely to cause a problem, and that a problem consistent with that expected is being seen. To wait for more is foolhardy - indeed sinful.

For instance, some scientists have suggested and are working on proving or disproving that increased temperatures, if they do exist, will cause more evaporation of ground and ocean water, which creates more clouds, which may block more sunlight, which could allow the earth to cool,

What is the temperature on Venus? About 464 °C on average. What is the temperature on Mercury? About 167°C on average. Why is Venus hotter?

No sources are cited again, but this argument appears to be quite wrong. If we warm the oceans they release more CO₂.

I wrote a post yesterday about Martin Durkin’s junk science programme on global warming designed to convince people with no knowledge of the issue that - in his words - global warming is not our fault. I took issue with a number of points, including the graph on which Durkin manipulated temperature data to make it look as though the post war cooling period was much larger than it actually was.

Someone (Jason) commented that my own graph, that I included for comparison, had a trend line that seemed to hide the post war cooling period. The graph had come from a previous article where it was demonstrating that the warming trend had not (contrary to the arguments of some) stopped in 1999. The trend line is superfluous to establishing the deceit of Durkin’s graph.

Whilst the data is quite clear in the graph, demonstrating the point, I considered the point, and thought that it would be better if I construct a new graph, comparing Durkin’s data and at least one well respected source of historic climate data. I have used Crutem 3v, because I had it available after creating the previous graph.

The problem is that Durkin’s data is not published anywhere. The “source: NASA” attribution hides the fact that the graph has been redrawn and in fact now matches no known data set. Thus I carefully used a ruler(!!) to reconstruct the data set from Durkin’s graph. It is not perfect, but it is pretty close. (You can check it against the original included in yesterday’s post).

I then plotted Durkin and the Crutem 3v dataset (which is a bit “wiggly lined” in Durkin’s words). In order to average out the wiggly lines and make it more directly comparable with Durkin’s data, I calculated a 10 year moving average and plotted this.

This average, I think, suggests that Durkin’s dates are a little off in his data - but the shapes do approximate to something similar (a 5 year moving average was too granular for Durkin’s graph).

So here is the complete graph. Click on the thumbnail to see it full size. I have shaded the same area that Durkin shaded - the period of post war cooling due to industrial aerosols prior to the agreements to reduce these. Notice particularly how much more strongly the temperature anomaly grows after this period than in Durkin’s graph. Bear in mind that in Durkin’s graph, his team made up these data for this period.

I wrote the other day about the “Global Warming Swindle” programme on channel 4 recently, and how one of the scientists, Carl Wunsch, has objected to how he has been misquoted and edited to seem to be saying the opposite of what he was actually saying.

Someone replied to me:

Aside from Carl Wunsch, all the other Scientists interviewed in the documentary were very strident in their views that Co2 is irrelevant to climate change, and that the scientific data points to the sun as the major driver in climate change, and that the Global Warming Theory is nothing more than hype and panic dressed up as science.

Why not explain how the rest of the scientists interviewed have no credentials? Regardless of who was interviewing them, (Durkin) they made their views very clear.

I have no intention of attacking the credentials of the scientists involved, as that would be ad hominem. It is relevant that the programme makers have no scientific background, because of the way they have consistently, over the course of a decade,
misrepresented science. As journalists, their lack of scientific balance creates good controversy, which is good for their ratings.

But it is not balanced, considered or scientific.

Whilst I won’t indulge in ad hominem attacks on the scientists, I do note that there was no new material in this programme, and every point raised has been refuted before (and much of it was downright wrong!)

I mentioned that the graph looked like it had been doctored to exaggerate the post war cooling. “The Independent”, a British newspaper, looked into that very point. They asked channel 4 and the programme makers where the data had come from. The graph on the programme (click on the thumbnail to the right to see this graph full size), the source claims to be NASA. However, Durkin eventually admitted that it had been taken from another obscure publication published in the medical sentinal by some climate change sceptics. Further investigation revealed no such diagram, but something similar for terrestrial northern hemisphere temperatures from weather stations in the top third of the globe.

Eventually the data was tracked down to some data that had come from NASA but ended in the 1980s. It turns out that the line from the early 1980s onwards was extended by hand, and not correctly (and even then only to the year 2000). Mr Durkin admitted that his graphics team had extended the time axis along the bottom of the graph to the year 2000. “There was a fluff there,” he said. He also said: “The original Nasa data was very wiggly-lined and we wanted the simplest line we could find.”

I downloaded two data sets and plotted the results, and you can see how different the graph should actually look (click the thumbnail on the right for fullo sized image).

Now what about what the scientists said? The cosmic ray theory is part of a new book by Nigel Calder and Henrik Svensmark. The fundamental flaw with the theory is that whilst Svensmark posits a role for cosmic rays in cloud formation, there is no trend in cosmic rays, and there is no trend in cloud formation. Dr Gavin Scmidt from Nasa demonstrates five missing steps from Svensmark’s data to his conclusions in his press release (and now his book).

“We’ve often criticised press releases that we felt gave misleading impressions of the underlying work,” Schmidt says, “but this example is by far the most blatant extrapolation beyond reasonableness that we have seen.” None of this seems to have troubled the programme makers, who report the cosmic ray theory as if it were an accepted (and indeed only acceptable) explanation.

As “the Guardian” reports:

Professor John Christy speaks about the discrepancy he discovered between temperatures at the Earth’s surface and temperatures in the troposphere (or lower atmosphere). But the programme fails to mention that in 2005 his data were proved wrong, by three papers in Science magazine. Christy himself admitted last year that he was mistaken. He was one of the authors of a paper which states the opposite of what he says in the film. “Previously reported discrepancies between the amount of warming near the surface and higher in the atmosphere have been used to challenge the reliability of climate models and the reality of human-induced global warming. Specifically, surface data showed substantial global-average warming, while early versions of satellite and radiosonde data showed little or no warming above the surface. This significant discrepancy no longer exists because errors in the satellite and radiosonde data have been identified and corrected.”

Also from the Guardian:

The film’s main contention is that the current increase in global temperatures is caused not by rising greenhouse gases, but by changes in the activity of the sun. It is built around the discovery in 1991 by the Danish atmospheric physicist Dr Eigil Friis-Christensen that recent temperature variations on Earth are in “strikingly good agreement” with the length of the cycle of sunspots. Unfortunately, he found nothing of the kind. A paper published in the journal Eos in 2004 reveals that the “agreement” was the result of “incorrect handling of the physical data”. The real data for recent years show the opposite: that the length of the sunspot cycle has declined, while temperatures have risen. When this error was exposed, Friis-Christensen and his co-author published a new paper, purporting to produce similar results. But this too turned out to be an artefact of mistakes - in this case in their arithmetic. So Friis-Christensen and another author developed yet another means of demonstrating that the sun is responsible, claiming to have discovered a remarkable agreement between cosmic radiation influenced by the sun and global cloud cover. This is the mechanism the film proposes for global warming. But, yet again, the method was exposed as faulty. They had been using satellite data which did not in fact measure global cloud cover. A paper in the Journal of Atmospheric and Solar-Terrestrial Physics shows that, when the right data are used, a correlation is not found.

The programme failed to mention that we know now that the post war global cooling was caused by atmospheric aerosols, despite the fact this is now well understood. It did not mention that the medieval warm period was northern atlantic only. It did state that the medieval warm period was warmer in Europe than it is now, whereas we
know now that this was not so - that it is now considerably warmer than it was then. (16 year old data was used to contest the opposite).

The history was wrong too. The suggestion that Nigel Calder discovered someone with a novel theory about burning coal to create a greenhouse effect in the 1970s is about 100 years late. Svante Arrhenius discovered the greenhouse effect and suggested burning coal to warm up the climate in 1895. (He was Swedish, so perhaps felt a warmer climate would be agreeable!)

Tim Ball gave some of the most strident polemic with the least data. I cannot remember him making any scientific point (his specialism, when he was still publishing, was historical Canadian climate) but he made many specious claims. He said that it was as though a car was broken and the climate scientists ignore the engine and transmission and look at one bolt only to try and fix the engine.

That is exactly what he, and the other handful of sceptics on the programme were doing. They ignore all the climate science, and look at only a few narrow points that bolster their own opinions. The IPCC has looked at solar forcings and included these in their report.

These sceptics are ignoring the science. Why? I don’t know. But just because a handful of scientists are looking at a single bolt, don’t ignore the thousands of diligent and intelligent scientists who have encountered all these issues and looked at them carefully, but are looking at the engine and transmission.

Viewers of channel 4 have been swindled by director Martin Durkin (again), and Carl Wunsch of MIT is angry about it. He was approached by Durkin to make a supposedly balanced film about global warming issues, getting away from the hysterical propoganda from the polarised political debate (particularly in the American political arena).

What concerned scientist would object to such a thing? But Durkin misled Wunsch. For instance, Wunsch writes:

In the part of the “Swindle” film where I am describing the fact that the ocean tends to expel carbon dioxide where it is warm, and to absorb it where it is cold, my intent was to explain that warming the ocean could be dangerous—because it is such a gigantic reservoir of carbon. By its placement in the film, it appears that I am saying that since carbon dioxide exists in the ocean in such large quantities, human influence must not be very important — diametrically opposite to the point I was making — which is that global warming is both real and threatening in many different ways, some unexpected.

You can read the whole of Carl Wunsch’s open letter.

So what do we make of this programme? It is the most biased an scientifically illiterate documentary I have seen in a while - but actually true to form for channel 4 and Durkin. In 1997 he made a series for Channel 4 called “Against Nature”, which compared environmentalists with Nazis, conspiring against the world’s poor. The people he interviewed thought that he was making a balanced critical examination of environmentalism, but the contributors were lied to about the contents of the programmes and given no chance to respond to the accusations the series made.

The Independent Television Commission handed down one of the most damning verdicts it has ever reached: the programme makers “distorted by selective editing” the views of the interviewees and “misled” them about the “content and purpose of the programmes when they agreed to take part.” Channel 4 was forced to make a humiliating prime time apology.

As formal complaints have made by this programme’s contributors too, we can but await another apology from channel 4. The question is why this channel ever agreed to use this same producer again.

A link to one of my articles on the Agricultural Biodiversity Weblog elicited a comment that included this:

The so-called ‘market economy’ (a euphemism for monopoly capitalism) is not environmentally sustainable, no matter how much green paint and promises of ‘eliminating poverty’, etc., you apply.

As a very ambivolent anti-capitalist, I found strong sympathy with that statement, and yet I find that I cannot agree. These are my reasons:

1. Capitalism is driven by greed and consumerism. It is an illogical and wasteful system, and one that has huge problems. However, whilst the greed leads to an anti-environmental cycle if left unchecked, it is nevertheless possible to intervene to use the assumptions of capitalism for environmental benefit. An example of this might be the EU emissions trading scheme, which puts a price on emission reduction, and thus generates a trade. Whilst the scheme is not perfect, it is better than hand wringing or sticking our heads in the ground and saying there is no problem (or the problem is intractable).

2. Capitalism is an organic system like any other. It may be a system driven to consume resources, but like any system, if the consumption is too aggressive, then there are negative feedbacks into the system that restrain it. (The problem being that the negative feedbacks perhaps kick in too late to be of any use to the people that are suffering now!)

3. Historically capitalism has been evil, and yet has paradoxically also been a great benefit. The UK invented capitalism with our industrial revolution. It could be argued that Wedgewood invented the idea of planned obsolesence, and modern marketing. In generating a market in patterned chinaware, he essentially began the whole process, even as indutrialisation was changing our landscape.

But here is the oddity - industrialisation created the terrible “labour market” whereby even skilled labourers would be stuck on subsistence wages, and any response to change in the labour market would take a generation to work through - which did not help those with skills no longer valued. But at the same time, the industrialised UK saw population growth - especially in industrialised towns, whilst non industrial countries saw famine and starvation that killed millions.

So unless we have a solution that is better for people than capitalism, we have to paraphrase Churchill et al. and say “Capitalism is the worst of all systems. Except for all the others”.

1. Finally, I am a pragmatist. The way to change the world is in small steps and individual changes.

A comment on another blog raised the question of whether environmentalism and international development are working at cross purposes. The argument is as follows:

In many ways Environmentalism and International Development are conflicting, if not totally incompatible agendas. Which is ironic, given that they tend to both be pushed by the same people, simultaneously. 1. Local food restricts developing countries’ access to world markets – thereby stunting their economic growth; 2. Organic and GM-free foods encourage biodiversity, but can’t possibly produce the yields needed to avert famines in the developing world; 3. So called ‘Fairtrade’ locks third world producers into inefficient, commodity-crop farming when they should be diversifying – thereby ensuring they will never earn more than just-above-poverty wages. These agenda are both essentially bourgeois. It’s alright for us in the west because we are rich and developed enough to be able to make these food choices without risk, but to enforce them on the developing world is a death sentence – economically, developmentally, and (in many cases) physically. Sadly, many on the left don’t actually want the third world to develop. They’d rather keep them in a mythical, agrarian ‘golden age’ and have this patronising view of people there as ‘noble savages’ – victims who need to be ‘saved’ from globalisation and the west. They can’t accept the unpalatable truth that what people in the developing world REALLY want is to be go-getting, middle-class capitalists like the rest of us.

Dizzy Thinks Blog

Now there is much to say here, but I intend to ignore the issue of whether the writer really understands what “the left” wants. (My argument would be that the right/left division is, in any case, essentially bogus).

On the assumption that we can agree that people have concern for the environment and compassion for the poor, and what to see an improvement in the condition of both, how do we answer these claims?

On point 1, does local food production restrict access of developing countries to local markets?

Well on some level there might be some truth in this. If we buy strawberries in february, where do they come from? Are they flown in from Africa?

Clearly that is an environmental disaster. We should eat fruit in season, and not pander to a must-have culture that ramps up the food miles and energy cost of growing foods. But if we do so, then we inhibit the ability of the African farmer to sell his crop on the world market.

But we are not locking the farmer out of the market. Instead, if we live by environmentally sound principles, we ensure that there is no market for strawberries in february. What will teh farmer do? diversify into a crop that he can sell. That is just market forces at work.

As long as the African farmer is free to sell any crop into our markets without restriction, there is not a problem.

But there is a problem, because we do lock African countries out of our markets. We prevent the market from working for the benefit of these farmers.

The answer is not to eat more strawberries. The answer is to free up the markets.

1. Organic production encourages biodiversity, yes. But it is a fundamental misunderstanding of the organic movement to think that this is the root of the movement (although the misconception is a common one, helped on by many who market organic food).

Organic production is primarily about sustainability. E.F. Schumacher wrote a book “Small is Beautiful” which made the point that fossil fuels are energy capital. They are a limited resource, and so good economic principles insist that we only spend the resource in ensuring sustainability.

So the point of organic production is precisely to get to a point where efficient sustainable production of food can indeed meet our needs. It can be done, but will only happen if we move step by step towards the goal.

1. Fairtrade does not lock producers into a crop. It guarantees a fair wage for that crop. Now that may seem artifically high for the crop, because non fair trade coffee can be purchased by companies for a lower price, and it may be that some of those selling at the lower price would do better to diversify.

What will happen? Those who should diversify will. The price of coffee paid to the grower will thus edge up, as demand outstrips supply, and everyone will benefit, without fair trade affecting anyone.

Now if a fair trade grower could earn more by diversifying, then they will also diversify. Indeed, the fair price for their crop will ensure that they have access to more capital to allow for the diversification.

The very idea that paying consumers less than a fair price for their crop will somehow economically benefit them is preposterous.

So this commentator is wrong on all points. Environmentalism is not an enemy of international development.

Indeed, there are some benefits from environmentalism. For instance, the disadvantaged nations of the world will be disproportionately worst hit by the effects of climate change. Efforts to tackle this problem (caused by the richer nations) will aid the third world.

After I wrote my piece in this blog about Dr Timothy Ball’s opinion piece, where he claims that no one is listening to him, even though he was one of Canada’s first climatology PhDs, and a researcher in the field - Dr Ball wrote me a reply in the comments section arguing that the piece was ad hominem.

As I pointed out to him, the piece was in fact evaluating an appeal to authority using the same criteria that I proposed for evaluating such appeals. It is entirely valid to review the expertise of an authority when such an appeal is made.

But Dr Ball made one point which I will deal with a little more fully here:

Elsewhere you (I assume it was you, but no matter because the point is still important) make the argument that there was no consensus on global cooling in the 1970s. First of all, as with global warming today, consensus is not a scientific fact. Second, as an active climatologist during that period I can attest there was a general consensus, but as with warming today there were those who disagreed that the trend would continue.

Now I am sure that these are Tim Ball’s recollections of the time, but as with all things, our recollections will be coloured by anecdotal evidence and specific converstaions we had. Was there ever hype about global cooling? Certainly, as articles in Newsweek and National Geographic demonstrate. Would Dr Ball have been asked about the issues? I presume so.

But was there a scientific consensus on the issue? Certainly not.

How do we know? The same way we know anything about what is happening in science - by reading the scientific literature.

And that is very revealing, because there is very little literature on the subject, and clearly no consensus.

There is a site that has set out to evaluate all papers from the time to examine this. The challenge on the site is to present any paper that predicts an ice age in the 1970s. Thus far there are some 16 links to papers, and no obvious link to global cooling. Indeed, the action of carbon dioxide in warming the climate is a stronger theme in these papers! But if we allowed all 16 papers as candidates - that is a long long way from a scientific consensus.

A good summary of the field is found in:

National Research Council, US Committee for the Global Atmospheric Research Program, Understanding Climatic Change: A Program for Action, National Academy of Sciences, Washington, DC, (1975), appendix A.

This paper has been summarised by W M Connolley, who also is gathering the other papers mentioned above. It is quite clear that (a) there was no consensus on global cooling, and (b) that the worldwide scientific consensus of the IPCC is wholly quantified where the above report only spoke of very small risks, without giving any numbers.

So what really happened in the 1970s? Essentially there was some cooling from the post war period into the 1970s as per the graph on the right.

No consensus was ever reached on the cause of the cooling, because at this time there was also a great deal of concern about acid rain. Consequently sulpher dioxide emissions were reduced through a series of international treaties and technological change. The result was that sulpher dioxide rapidly declined as an atmospheric aerosol. This had been very effectively masking the effects of carbon dioxide since the the second world war, and as sulpher dioxide emissions were reduced the temperatures started to rapidly climb.

This is all well known, and there has even been a half baked suggestion that we deliberately pump sulpher based aerosols into the atmosphere to keep global temperatures down!

What of the coverage in the popular press?

Well anyone who knows anything about science will be aware that the popular press love to latch on to preliminary studies - particularly when they are controversial, and make a big thing of them. The journalists do not quantify uncertainty in their reporting, and the result is a bit of hysteria, followed by ignorance of later refutations.

An example of this is seen, for instance, in breast feeding studies, where breast feeding has been linked to high IQ in the popular press. What the press do not mention is that earlier studies were contradictory, because they failed to factor in factors such that higher IQ mothers were more likely to breast feed. Even now that the science is settling, and it seems that there is a link between IQ and breast feeding, no-one actually mentions that whilst the effect is observable scientifically, we are not talking about an improvement that anyone would actually notice.

So don’t rely on the press for science reporting.

And in interests of balance, I will mention a recent article in “The Independent” which was predicting the possibility of extinction of life on earth at the upper end of the warming estimates from the IPCC. That was just as poor reporting as any I have seen on global warming science.

A comment on this blog points to three articles, all making the same points about there being a medieval warm period. The one below is typical:

Vikings raised crops and cattle in Greenland 1000 years ago, while Britons grew grapes in England

I have already answered the point about Greenland in an earlier post. However, I did not mention this bit about grapes being grown in Britain.

I just wanted to confirm that my parent’s house, built in 1900, has a grape vine growing on the south wall. It is by no means impossible to grow grapes in Britain (and not just because Britain is now warmer than it was in the medieval warm period. This vine has been there for a very long time. I do not know if it was planted when the house was built, but it must have been there for at least 50 years).