Global warming - it's OK to have doubts

What’s this chart all about?

It’s a potted history of our climate over the past 400,000 years. I got it off Wikipedia. The data is drawn from the Vostok camp in Antarctica where they have drilled down into the 4,000 metre-depth ice field and have been able to determine CO2 levels, methane levels and temperature throughout the period through which this ice field has been accumulating. It’s a fairly recent project and the data now forms part of our key understanding of how the climate has been shaping up.

The present time is on the left hand side. As you move right, you go back in time. The right hand edge is 400,000 years ago.
• The blue line on top indicates the amount of CO2.
• The red line is the temperature.
• The green line is methane.
• The jagged brown line is oxygen.
• The smooth brown curves right at the bottom is nothing to do with the data found in the ice cores but is someone trying to explain the variations in that data with reference to the Earth’s orbiting patterns, known as the Milankovitch cylces. If you want to know more about this, then head off into Wikipedia. It’s only a hypothesis and, judging by the best-fit they have managed to produce here, not a particularly convincing one!

What we are looking at here are four long ice ages broken up by four all-too-brief warm periods, known as interglacials, represented by the peaks. Each cycle seems to last about 100,000 years, consisting of around 10,000 years rapid warming, followed by a 90,000 year cooling-off period. The temperature variations are quite large. The coldest part of the ice age is around 10°C cooler than the warmest part of the interglacials.

We are of course in an interglacial period right now. In fact, it’s a remarkably long interglacial. The previous three all had very sharp peaks, suggesting a really warm period lasting no more than a couple of millennia. We are about 10,000 years past the end of the last ice age, which makes this easily the longest warm period during this 400,000 year epoch. I don’t think this means the next ice age is imminent: rather it suggests that something different is happening this time around. Of course, it is tempting to speculate that the flowering of human civilisation required an extra long interglacial. We perhaps needed 10,000 ice-free years to invent the iPod and to introduce congestion charging in London.

It seems unlikely that we humans have brought about this lengthy interglacial by our own actions. For its first 5,000 years, we were fumbling around in the Stone Ages and would surely have had zero impact on the environment. But as we began to clear forests and start farming, it is conceivable that our presence began to have an effect. But surely nothing like the effect we are now having since we worked out how to keep ourselves warm and well-lit and to propel ourselves around at great speed by burning fossil fuels. Is it possible that we could be about to extend this interglacial yet further by significantly altering the atmosphere? That is the big question.

Throughout this 400,000 year period, the chart shows that CO2 levels have bobbled about between 200 and 280 ppm (parts per million). However, in the past 200 years, since we started burning fossil fuels in large quantities, the CO2 levels have risen very dramatically, from around 280 up to nearly 400 ppm, and they continue to rise at around 1% per annum. That really is off the top of the scale. Fortunately, global temperatures — the red line on the chart — haven’t kept up in tandem, otherwise we’d have seen an increase of 10°C by now. But worryingly, sometime in the 1960s, global temperatures did start to rise and the rate of increase is starting to rise as well. To date, the temperature rise is still quite modest, at around 0.7°C above the long-term average, but the trend is becoming more and more noticeable.

The problem here is that there is no way of determining that the one factor — increasing CO2 levels — is causing the other — increasing temperatures. There is data coming in from all over the world and most of it confirms that the world is heating up. There is the greenhouse theory which provides a neat explanation of why this should be happening. But there is no way of proving it. The increasing temperature trend is still comparatively new and comparatively modest and we simply don’t know enough to be able to predict where it is heading in the future. All we can do is keep collecting data: the warmer the Earth gets, the more convincing the theory of global warming becomes. But anyone can see that at the moment there are still too many unknowns to sweep away all doubts about the theory.

These doubts shouldn’t be underestimated. I want to show that it is OK to have doubts and to express them publicly without fear of being ridiculed. Having doubts doesn’t make you a ‘global warming denier.’ At least, I hope it doesn’t, otherwise I will be in trouble.

There are lots of possible reasons why we may have overestimated the effect of releasing CO2 into the atmosphere. One that stands out is the miniscule quantity of CO2 up in the atmosphere even after we have been burning fossil fuels for two centuries. The very reason climatologists refer to CO2 levels in Parts Per Million is because, if they express them as a percentage, it’s such a small figure that they risk getting decimal point errors. 400 ppm is in fact 0.04%. Put another way, oxygen, which makes up just over 20% of the Earth’s atmosphere, would come in at 209,000 ppm. CO2 really is just a tiny trace element in the atmosphere and even if we burned every available bit of fossil fuel we have, it’s unlikely that we would nudge CO2 levels much above 0.1% of the total. So it could well be that the effect of increasing CO2 levels could be very muted indeed and that we shouldn’t get too worried about it. On the other hand, the changes we are bringing to the atmosphere could bring about some very large and unpredictable alterations to the global climate. That of course is the fear.

We still probably have time to change our habits but it’s hard to see this happening without a fair bit more proof that we are cooking ourselves. In summary, I think it is quite possible — sensible even — to be both very worried about what we may be doing to the climate and yet to question the data coming in. In other words, to maintain a healthy scepticism.

Global warming...an answer of sorts

Following on from the previous post, readers will be pleased to know that I got to the meeting on Saturday night and saw Jeremy Leggett and Tony Juniper in action. There were about 60 people there and there were more questions than could possibly be dealt with in the hour allocated to the debate. The questioning was very friendly and included the hoary old chestnut “Which is worse? The government or the big oil companies?” To which of course there is no answer except that Bush’s government and Exxon are the worst of a bad bunch.

The question which I wanted to answer had to wait till afterwards. I asked Tony Juniper what would happen to all that CO2 we have released into the atmosphere. He understood the question but his answer was, I thought, just a tad waffly. He said he thought it would eventually be sequestered by the oceans and forests and that there was real hope that, if we could keep the carbon levels at under 550ppm, CO2 levels would start falling back towards the pre-industrial levels of 280ppm (they are currently around 400ppm). I must say my immediate feeling was one of relief: maybe we can crack this problem? But the nagging doubts soon returned. What if the levels don’t go down? And who the hell knows? Isn’t this yet more speculation? Are we just being fed a way out so we don’t all get existential and go top ourselves?

Wikipedia is good on carbon sequestration. It sort of happens naturally. The forests do it, as we all know, but the oceans do it as well. In fact, it speculates that plankton extract carbon to build their shells from CO2 and that, when they die, they drift to the ocean floor and gradually solidify to eventually become fossil fuels. But of course it’s a slow process. If, as has been speculated, we are burning through carbon at 400 times the rate it gets sequestered by the oceans, it’s going to take an awful long time to get our CO2 levels back to 280ppm. 108,000 years to be precise! Unless we can find a way of speeding it up. Now that is speculation.

Last point. PPM. What is it? Parts per million. That’s how much CO2 there is up there, measured by volume, not weight. Nitrogen is No 1 at 780,000ppm or 78%, oxygen second at 209,000ppm or 20%, argon trails in at third place with 9,000ppm or 0.9%. CO2 is in fourth place but it’s way behind at 400ppm or 0.04%. So it really is a tiny speck of gas compared to the main constituents. So, although we are on course to double the amount of CO2 out there by 2150, it’s still only the difference between 0.028% and 0.055% of the atmosphere.

Millions at risk?

The Independent’s been at it again. Another front page global warming scare story (Sat April 15th) which slaps “3 degrees” across the middle underneath a strapline saying “Chief Scientist warns bigger rise in world’s temperature will put 400 million at risk.” And, quite subliminally, as if to let us know not to be too worried, this same front page also carries a 50mm deep blue advertising band, separating the title from the main story, offering us to “Win a Return Flight to New York – see page 50.” I love irony.

This is typical of the mixed messages coming out of our media and shows the thoroughly schizoid state we are getting ourselves into over global warming. If we are all going to roast in hell, we might as well enjoy the last few pleasurable moments we have left to us. “Anyone fancy going to Mauritius for Christmas?”

So what is it the Chief Scientist is saying? And, more to the point, who exactly is the “Chief Scientist” in the first place? Is he the science tsar? Or is his post altogether different? How does one grow up to become a Chief Scientist? Do we have a Chief Artist? And is there really a Ministry of Magic?

OK, OK, I can’t actually begin to answer any of these questions, but I can report what Sir David King (for he is it is who is the Chief Scientist) was reported to have said. It was only a few weeks ago that he told us that global warming is a bigger threat than terrorism. He may well be right, but it strikes me that this is the stuff of idle speculation – it has very little to do with science or scientific theory, which is what you might expect the Chief Scientist to be good at. It supposes that he knows what threat is posed by both global warming AND terrorism is able to make a logical comparison of the two. Which seems to me to be a bit far fetched. It could be that the threat from both is negligible and that bird flu actually turns out to be the really big nasty. But that’s just idle speculation on my part and I am not Chief Scientist. Not Chief Anything in fact, but are my speculations any less valid than those of the Chief Scientist? What powers has he gained in becoming Chief Scientist that make his speculations so much more valuable and insightful than anyone else’s? OK, I mean mine in particular. Maybe I should appoint myself Chief Critic. It is a skill, of sorts, and my family keep telling me I am all too good at it.

OK. Back to Sir David. What he has been saying this time around is that we aren’t going to hit two degrees temperature rise, which is what the politicians would like, but it will probably be nearer three. Hence the Indie’s helpful headline “3 degrees.” Now hold on a minute. There seems to be something I have missed here. We all now know that we are pumping huge amounts of CO2 out into the atmosphere. Every year we are adding about 1% to the total of what’s already floating around up in the sky. We all know the Earth is heating up, except (apparently) David Bellamy who thinks it’s gently cooling down. Well, you can’t please everyone and he’s very much not the Chief Scientist anymore. Sir David King (who is the man) is good on graphs showing just how much more CO2 is around now than there has been in the past 60,000 years. Take a peek at his PowerPoint presentation, given as the Greenpeace Business Lecture in 2004. I am convinced. I don’t need to be reminded once a week. I am a little bit frightened. I am also frightened of Muslim extremists and I fear for the safety of my eldest son who wants to drive around the country lanes like a boy racer, now that he is 17. You’ve got me frightened, but not yet frightened enough to lie awake at night worrying about it, or to stop flying, or buying imported salad from Waitrose.

What worries me here is that you can only go so far with the science bit and after that it’s off into the world of speculation. Like, will the world heat up by 2 degrees or 3 degrees? And, even more so, what on earth will be the effect of all this? It doesn’t help that much of this speculation is counter-intuitive. Many people speculate that far from getting hotter, the UK may actually get colder because the Gulf Stream will be obliterated by cold currents coming down from that patch of sea between Greenland and Canada. This doesn’t sound nice but it’s hardly apocalyptic. I am sure we would survive colder winters.

But there’s another, more fundamental problem I am having. All anyone is really talking about is slowing down the rate at which we release CO2 into the atmosphere. Not stopping it altogether, just slowing it down. Now, is the amount of CO2 up there going to decrease if we start slowing down our release rates? I don’t think so. It’s already at record levels. Even if we stopped tomorrow, it might be all too much for our atmosphere. People speculate about their being a tipping point after which the climate goes into freefall, but no one has a clue where or when that might be. At the moment, all we can really hope to do is to postpone the day when we finally bake to a crisp. If we follow George Bush, it will be 2100. If we follow Friends of the Earth it will be 2200. At least I think so. Despite having been a keen student of this issue since the 1970s, the truth is I have no idea.

Help is, however, at hand. On Saturday evening, if all goes to plan, I am going to see two real environmentalists in action. Jeremy Leggett, once Chief Scientist at Greenpeace (surely there can’t be two Chief Scientists? Or did the government steal the idea off Greenpeace?), now supremo of Solar Century, the PV cell people, and Tony Juniper, Executive Director of Friends of the Earth. They are “in conversation” as part of the Cambridge Word Fest, an event I was completely unaware of until yesterday. Hopefully at least one of them will be able to give a definitive answer to my question “Is all this CO2 just going to float around the atmosphere indefinitely?” and maybe even a supplementary “Should we be thinking of ways of returning all that CO2 back under the ground where it came from?” Will they have a convincing answer, or will it be more speculation?

Maybe we’ll find a way of making fossils rather than burning them? Maybe we are on the verge of a new technology, climate farming. Maybe in a hundred years time we will look back on this as the time we began to work out how to manage the atmosphere rather than sitting around like dinosaurs waiting for the extinction event to engulf us all. Or maybe we are all doomed. I really have no idea, but it’s fun to speculate.

Green Switch Off

Our house is designed with a walk-in pantry. How very now, I hear you thinking. Only it’s never quite been the wonderful place I thought it might turn into. It’s not a spot the kids choose to hang out in on a Tuesday evening, or a venue to discuss village gossip with a neighbour. It’s just a plain old storeroom, stuck across the utility room at a somewhat annoying distance from the main kitchen area. You have to avoid dogs, washing and odd bits of hardware spread across your path to get into the pantry, so it’s a sort of inconvenient convenience store.

It is lit by a single bulb. No architectural lighting features here. There are no windows, just a breeze hole at the far end, so without the light being switched on it’s really a bit desperate in there. Being a family with three slobby boys, the light was of course always being left on, sometimes overnight. Now, as a paid up member of the grumpy-green tendency, you can imagine just how my blood pressure would head up off the scale when being confronted with a light left on overnight.

Three years ago, I hit on a plan. I pitched up an electrical wholesaler one day and bought a time-lag switch. Maybe you’ve seen them? Instead of flicking a switch on or off, you press a big button inwards, the light comes on and then slowly the button works itself back out to the off position and the light turns off when the contact is broken, after a time delay of a couple of minutes. The time delay is adjustable. They are dead easy to fit – the slip into a regular switch backplate with the same electrical screws. Great idea, but how would it go down?

I snuck in and did the job with the aid of a torch (there being no light available whilst I changed over). It took maybe three minutes. Then I sat back and waited for howls of protest from wife and/or sons. “What have you done to the bloody light switch, you twat” or some such family bonhomie. But the funny thing is the protest never came. I think they actually liked the light switch. Once the novelty of a push-in light switch had worn off, we grew to enjoy the way it worked. There is a somewhat pleasing, sensual quality to being able to push a light switch inwards. More biological than mechanical. Maybe it was to be a small green success story?

Well yes and no. About six months ago, the switch started sticking in the on position and on a couple of mornings I found the pantry light on and the push-in switch in a state of permanent depression. Now, far from being an energy saving device, it was in danger of becoming an energy waster because it’s not easy to turn the light off, if it doesn’t do it itself. You have to tug at the button and persuade it to start its outward journey. It misbehaved two, maybe three times and then it seemed to fix itself. Or so I thought.

Then last week, I was rummaging round in the vegetable rack, just next to the switch, and accidentally knocked the switch with a bag of parsnips. The push button popped out of its socket, rolled across the shelf and came to rest on the floor. The light immediately went out, so I picked up the push-button and stuck it back in its hole, and pressed it in to bring the light back on. Voila! It wasn’t broken after all! Thinking how clever to get that fixed so easily, I got the onions I was after and went into the kitchen. Then, two minutes later, I heard a ping followed by the clattering sound of the push-button hitting the floor again.

The switch still works but every time it reaches the off position, it comes loose from its moorings and pings out across the shelf. I’m buggered if I can work out how to fix it. I put a wire basket underneath the switch to catch the push-button before it falls on the floor, but it’s not what I’d call an ideal solution.

So tonight, I went on line to the TLC website and ordered a replacement. They are called Time Lag Switches and they cost around £15. I wonder if the replacement will fare any better than the last one?

On conservatories

The conservatory industry exists in its own little bubble. It’s obviously related to mainstream building, to home improvements and the world of extensions, but it is the province of specialists who, by and large, don’t do much else. There are over 200,000 new conservatories built in the UK each year — that’s a phenomenal number, more than the number of new homes being built.
The question is why? There are one or two things that conservatories have going for them which can make them a very cheap way of gaining extra space. One is that they very rarely require planning permission. Another is that they very rarely require building regulations. Thus the two big administrative heavyweights, designed to send us bonkers, are, at a stroke, banished from the world of conservatories. You can just go and order one and you don’t have to bother with red tape. Of course, Britain being what it is today, there are numerous exceptions to these rules. “Very rarely” doesn’t mean “never.”
You don’t need planning permission if the conservatory falls within the permitted development rights of the house. For a look at what these might be, type "PD Rights" into the search field and follow the link. If your house has already used up its PD rights or hasn’t got any, then you will need to apply for PP.
The situation with building regs is rather more complex. Most conservatories don’t need to trouble the building control department but there are some aspects of conservatory building which will come into the building regs ambit, forming a nice grey area (shall I? shan’t I?). To avoid having to apply for building regs:
• the floor area must be less than 30 sq m (though it’s only 8 sq m in Scotland)
• the conservatory must not form part of the ‘heated envelope’ of the house – i.e. there must be separating doors
• the roof is at least 75% glass or polycarb sheeting
• the walls are at least 50% glass or polycarb sheeting
• the conservatory must all be at least 1m from the garden boundary
• it must be at ground level
Now that does cover the great bulk of bolt-on conservatories, but it might not cover yours. But even if your planned conservatory falls outside building regs, you are still required to comply with the safety glazing directives (in Part N of the building regs) and also if you have any electrics installed, it becomes a notifiable event, if not carried out by a competent electrician who can sign it all off against his insurance. There is also potentially a nasty little problem to do with conservatories being located under means-of-escape or egress windows, which some local authorities seem to be more concerned about than others. This is a complicated area because first-floor windows have only had to be egress since 2002, so it cannot logically be applied to the 98% of the UK housing stock that was never built with egress windows. It is the sort of grey area where you might want to think about installing mains-operated smoke detectors in the house, which is in fact the single most effective fire safety measure you can make to an existing dwelling.
There is no requirement for conservatories to be double-glazed (unless you want to build one in the Irish Republic). However, if you want to make the conservatory a “walk-through” feature with no dividing doors, then the price you have to pay is that the conservatory will be assessed as part of the normal living space and it will have to meet exacting energy efficiency standards, which will certainly include double glazing.
Why bother?
So much for red tape. The bigger question is, why bother to fit a conservatory at all? If you like gardening, why not build a greenhouse? If you like light, why not build an extension with lots of glazing? If you like sunbathing, why not buy a timeshare in Tenerife? Or a sunlamp? Why are there 200,000 conservatories added onto existing homes each year? Could it be that, for most people, it’s seen as a cheap way of getting an extension? Yes, I think it just might. For whilst there are the odd aspirational companies around like Amdega who sell a very upmarket product at prices way in excess of normal extensions, the great bulk of the conservatory market is made up of the sort of thing you can pick up at Wickes for under £2,500. It’ll be built-up off a brick plinth, itself built-up of pretty minimal foundations, and it’ll be stuck onto the back of the house with a few screws and the roof will have a stuck-on flashing connecting it to the main house. If it leaks, it’s really not a disaster, and if there is a little subsidence, then that won’t really matter that much either. In fact, this sort of conservatory is a throw back to how we used to build in days of yore, and how they build shanty towns today in Brazil. Bash it up – it’ll do.
Now it’s easy to be sniffy about this sort of building, but it does have a place. If you haven’t got a lot of dosh and your house is just too cramped, then a bolt-on uPVC conservatory may be just brilliant for you, especially as you don’t have to be bothered with the boys from the council crawling all over your house. You know it’s never going to feature on Grand Designs, so what?
The upmarket options
There is a yawning gulf between these bolt-on plastic extensions (95% of the market) and the beautiful one-off designs you see in the magazine adverts. An up-market conservatory will cost rather more to build than a conventional extension. There is a surprising correlation with the kitchen market where you can easily put in a fitted kitchen into a modest house for under £3,000, but the top of the range can cost more than ten or twenty times as much. For a start, if the conservatory design tips into the zone where you have to have building control involved — and it will if it is large or there is no thermal break between the house and the conservatory — then the full weight of the energy efficiency regs comes into effect. This loosely means that glazing to have a maximum U value of 1.8, which translates as argon-filled, low-e coatings and large air gaps. The cost of the glazing jumps from around £25 per sq m up to over £80 per sq m, which makes it more expensive than conventional walling or roofing materials. Having spent all this money, you then have to think about having a very cold space in winter (do you provide heating?) and a very hot space in summer (blinds? ventilation?). You can, of course, choose to not use your conservatory when it’s either too hot or too cold or too dark, but that’s an awful lot of times for a room that’s so expensive to build, and it makes little sense when you consider the size of the initial investment.

On solar panels

Leaving aside any green feelings you might have about saving the planet, the brutal economic reality is that roof-mounted hot water solar panels have not been a good investment. At a typical installed cost of between £2,000 and £3,000, and rather more than this for the more efficient evacuated tube systems (pictured), you would need to save £300 a year on your fuel bills to get a ten-year return, and this was never going to happen. The harsh reality has always been that your roof panels would be defunct before your investment could ever be repaid.

But, and it’s a big but, times change.

• 1. There are newly announced government grants, available in England & Wales, to reduce the installation costs of solar panels. It’s only £400 but it’s a start.

• 2. We are now living with much higher fuel charges, which increase the savings brought about by installing solar panels.

•3. We are using more hot water than ever. The more we use, the more useful solar panels become, for they are quite capable of producing bucket loads of hot water when the sun shines. In fact, during the summer months, they produce far more hot water than you could realistically use. In the winter, things are rather different, but even if you assume that solar panels only contribute meaningful supplies of hot water for six months of the year, the economic calculus is turning in their favour.

So what do the calculations currently look like?

Roof mounted solar panels can supply you with an average of 300 litres of hot water each a day for maybe six months of the year, provided you have a big enough cylinder to store the hot water.

That 300litres requires 25kWh of heat to lift the temperature through 50°C.
• via a gas-fired boiler, this would cost 70p a day, potential saving £125/annum
• via an oil-fired boiler, this would cost £1.00p, potential saving £175/annum
• via an electric heat pump, this would cost 80p per day, potential saving £150/annum

This assumes that you would actually use 300litres of hot water every day during the summer. It’s a lot but it’s more or less what our family of five consumes so it’s not inconceivable.

What this means is that for the first time there is a payback on solar panels that is shorter than their lifespan, generally agreed at between 20 and 25 years. It’s still above that magic ten-year payback period at which financiers tend to get interested but, in the case of oil-fired systems, it’s not that far off. It would take another 25% hike in oil prices to make solar panels a gilt-edged investment, without any grant aid. You’d still need to be a fairly big water consumer and you’d need to have your hot water storage optimised, so it wouldn’t suit every household for sure. But it still represents a major sea change for the solar panel industry. If you take a view that energy prices will, say, double within the next twenty years — and oil has trebled in the past six — then solar panels are already a very solid investment.

PS The payback time on installing photovoltaic panels — the ones which produce electricity, rather than hot water — is still way longer than their anticipated lifespan.

What the ODPM won’t tell you about the new Part L

Walls — 0.27
Flat ceiling — 0.16
Pitched roof — 0.20
Floor — 0.22
Windows — 1.8
A-rated boiler
Pay close attention to air leakage paths
Be prepared for an air-tightness test but don’t be worried about it

That’s it. Those are the U values and the details you will need to get your new detached house through the new Part L of the England & Wales building regs, which came into play at the beginning of April.

Funnily enough, you won’t find this information in the section of Part L that looks at building new homes, Part L1A. This is because we are meant to be moving to a whole house heat loss approach. This is a fine thing in principle as it recognises that the energy performance of a dwelling is dependent on a variety of factors. The regs suggest that you should have a target carbon emission figure for each house and that it’s up to the designers to figure out how they meet that target. But that doesn’t help designers a great deal because you have to put your designs through a process known as a SAP calculation in order to know what your emission rate is likely to be. You can do this manually via the BRE’s SAP 2005 calculations sheet (warning: it’s six pages and has 120 different steps to go through, many with look-up tables, before you get an answer) or you can do it using software but this is stuff you have to purchase. It’s not the sort of process a house designer is really geared up for: they want to know how much insulation they have to squeeze into the fabric.

But contacts of mine in the insulation business have been busying themselves with the new calculations and are coming up with model designs that will meet the new regs. And that one at the top of this article looks like the dog’s bollocks as regards detached new houses.

Oh, and it looks like bad news for Actis and the multifoil kids. Despite my contact Charlie Duke showing that Actis works pretty well, the powers-that-be are going to require that all insulation meets standard BR443 after 1 Jan 2007. BR443 states that thermal insulation has to have a European Technical Approval to be permissible. That means, in short order, that the insulation has to pass muster with the standard test, the guarded hot box test, which the multifoils don’t do.