Image source: Taiga Company.

1) If you buy just one new appliance in 2010, make it a really efficient fridge-freezer. The improvements in the energy use of the best fridge-freezers have been really impressive in the last few years. If you have an old refrigerator, it may be responsible for as much as a sixth of your electricity bill. A good new machine might use less than a half as much power, particularly if it is not too large. A second benefit is that by choosing to buy a really efficient refrigerator you will be sending a clear signal to the manufacturers that energy consumption matters. An impressive new web site – www.energytariff.co.uk – allows you to compare the electricity used by almost all the appliances currently in UK shops. You can make well-informed choices from your computer.

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2) Buy fewer, better clothes that are easy to wash. The worldwide textile manufacturing industry is a major user of energy. Additionally, growing natural fibres such as cotton or wool creates substantial volumes of emissions. A light woollen sweater might be responsible for over 40 kilograms of emissions before it gets to the shop. Even a T-shirt can embody over 6 kilograms of CO2 and other greenhouse gases. The average Briton buys seven of these a year. Could you make do with buying fewer, and making sure that they last longer? Buy organic cotton and you also know that your garment hasn’t added to the serious problems of pesticide pollution in central Asia. Can you switch to man-made fibres for some of your clothing? These fabrics generally last longer and can be washed at low temperatures, using less energy.

3) Think about trading in your car for membership in a car-share club. If you are typical, you use your car for one hour a day but pay for all 24. A car sitting at the kerb has to be insured, financed and maintained even if you hardly use it. Commercially run ‘car clubs’ are growing fast in many cities. They offer rentals from as little as £3.95 an hour or cars can be hired by the week from locations within a few minutes’ walk of your home. Car clubs reduce the cost of motoring for many people and each rented vehicle takes several private cars off the road. If there are no clubs in your area, simply sharing a car with neighbours may be a good alternative.

4) Look at the costs and benefits of putting solar panels on your roof. In April next year the government is introducing a new scheme to persuade us to generate our own electricity from photovoltaic panels. For every unit of electricity produced, the householder will get paid over 36p, around three times the price we are currently paying the electricity company for the power that we use. Solar panels are also coming down in price, meaning that on south-facing roofs in southern Britain you can expect a financial return of about 7% a year on your investment. It isn’t riches, but it certainly beats the interest you can get in a bank. Equally important, families that generate their own electricity seem to become more conscious of their energy consumption and focus successfully on cutting all their utility bills.

5) Eat less beef. The intensive rearing of cattle is a major contributor to greenhouse gases. These animals produce methane in their digestive processes and slurry heaps also generate large amounts of this powerful global-warming gas. What’s more, cows on most farms are fed large amounts of maize and other feed during the winter months. Growing these grains took energy and considerable amounts of artificial fertilizers. And as more and more of the world’s population demands meat in their diets, the pressure to cut down forests to create open pasture land increases. Perhaps 20% of the average Western carbon footprint is created in the food production chain and reducing the amount of beef eaten is an important step you can take to reduce this figure.

6) Try the new energy-efficient lights – LEDs. Many homes have replaced all their larger bulbs with energy-efficiency fluorescent lights. But many homes still have tens of halogen bulbs in kitchens and bathrooms. They use a lot of power and regularly need replacing. A new technology – LED lighting – uses only tiny amounts of electricity and directly replaces the small halogen downlighters. It’s only really in the past year that LED lights have become realistic alternatives. Before, they tended to have an unattractive blue colour and not produce enough light. But after recent improvements, now is the time to try some in your kitchen. They’re not cheap, but they’ll save significant amounts of electricity and will last for decades.

7) Keep your electronic devices for longer. Some of Apple’s fancy new computers have footprints of about half a tonne of CO2. This may be substantially greater than the CO2 produced generating the electricity that the computer uses in its lifetime. This could also be true for your new phone or your laptop. Although no one argues that you should waste power by unnecessarily leaving your gadgets on, the main focus should be on keeping them for longer. Doubling the average lifetime of our PCs and mobile phones would have a much more important impact than always turning them off at the mains socket.

8) Get better central heating controls. We all know that houses should be better insulated and have more efficient boilers. But for some households it may be simpler and less expensive to improve the heating controls. Check that all the household radiators have thermostatic valves. Make sure that they are turned off in rarely used rooms. Should your central heating be programmed to turn off earlier in the evening? Can you install a new computerised thermostat, such as the Dataterm (www.warmworld.co.uk), which will intelligently work out when your heating needs to be on or off? Running your heating with more care can save at least as much as investing in a new boiler. It doesn’t necessarily require you to run your house at a lower and less comfortable temperature.

9) Use the train to get to your holiday. Why not catch a train to the Mediterranean rather than driving or flying? The trip from London to Marseille can take as little as six and a half hours and you get to see something of France on the way. Book in advance and the one-way price is only £62, no more than a typical air fare. It’s similar with train travel in the UK. Going to popular UK holiday destinations by rail will almost certainly save you time and money and you can usually hire a car at the resort when you need it. Not flying to your holiday destination will probably reduce your carbon footprint by at least as much as any of the other choices in this list.

10) Grow some of your own food. Enthusiastically cultivated, a standard urban allotment can provide all the vegetables for a family of four for half of the year. In our household, we’re still eating home-produced tomatoes and lettuces grown under cover. If these vegetables had been grown in a heated Dutch greenhouse using large amounts of artificial fertilizer, shipped in a refrigerated lorry to a huge warehouse and then sold from an open chiller cabinet in a supermarket to which we’d driven, the carbon cost would be a thousand times greater. The advantages of local food are sometimes exaggerated: the greenhouse gas cost of South African apples may be no greater than English fruit kept in a cold store for months. But the footprint of seasonal produce that you grow yourself is tiny, and may even help wean your family off processed food.

11) Support international agencies trying to decrease the worldwide growth of population. The world now has over 6.7bn people, probably rising to well over 9bn by 2050. Each additional person adds to the strain on the planet’s ecology. Mike Berners-Lee, a leading researcher on carbon footprints, says in his new book, How Bad Are Bananas?, that a baby born today will add almost 400 tonnes to the UK’s emissions over his or her lifetime, even if we reduce greenhouse gases as fast as the government intends over the next decades. Cutting population growth is a vital part of any global strategy for averting the worst effects of global warming. In countless places around the world it has been shown that improving women’s education and giving easy access to family planning helps reduce the number of children in each family. As well as reducing fossil fuel use and minimising forest loss, we must therefore help women in poorer countries manage their own fertility.



A shorter version of this article appeared in the Sunday Times on 29 November 2009.

Lord Stern says the meat industry damages the environment. Image source: VirtualTourist.com

Clearly irritated that his argument in an interview in the Times had been boiled down to a ‘go veggie to save the planet’ headline, Nicholas Stern has issued a clarifying statement:

I think that once people understand the great risks that climate change poses, they will naturally want to choose products and services that cause little or no emissions of greenhouse gases, which means ‘low-carbon consumption’. This will apply across the board, including electricity, heating, transport and food. A diet that relies heavily on meat production results in higher emissions than a typical vegetarian diet. Different individuals will make different choices. However, the debate about climate change should not be dumbed down to a single slogan, such as ‘give up meat to save the planet’.

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Without representing his position as advocacy for veganism, Stern’s point on food is correct: the average western diet makes a very substantial contribution to climate change. Rough calculations suggest that food production is responsible for between 15% and 20% of total UK greenhouse gas emissions. Food miles are important and the electricity consumption of a big supermarket might surprise you. But the really serious issue is the intensive farming of livestock, particularly cows and sheep, which generate as much as a half of the total emissions. One study from 2007 suggested that the CO2-equivalent emissions of global warming gases from beef production could be as much as 50 times the weight of the meat itself.

There are three elements to the problem: farmed livestock eat large quantities of grain, they belch methane and they use land that might otherwise be forest. To get a kilo of beef, the animal typically eats about eight kilos of grain. That corn or wheat took energy to grow, required a lot of artificial fertiliser and then needed to be processed into a cake for cattle. Some of the fertiliser applied to fields breaks down into nitrous oxide, a far more powerful global warming gas than carbon dioxide. Cows and sheep emit methane as bacteria in their digestive tracts digest the cellulose in plants. And, worldwide, the gradual increase in the consumption of meat creates pressure to cut down forests to create new pastureland and cropland for grains to help feed the livestock.

As countries get more prosperous, their populations tend to eat more meat. So unless we do something, the impacts of livestock farming are probably going to get worse. And, by the way, it isn’t just meat. The same arguments apply, albeit with less force, to dairy products as well. The best diet from a climate point of view is probably a mixture of dried plant-based foods, such as beans and nuts, with large quantities of locally grown seasonal vegetables and fruits. It may also be best for our health and it would certainly save us money. In fact, the simplest and cheapest way of largely meeting your commitment to the 10:10 campaign would probably be to eat vegan foods for half the week. To many people this will seem a less demanding challenge than not flying for a summer holiday.

Nevertheless, the reaction to Lord Stern’s statement has been unpleasantly vicious. People have seen his views as another illustration of how “climate change” will be used as an excuse for the elite to limit the choices of ordinary people. We are already being told to drive less, not to fly and to buy dim lightbulbs. Stern’s comments suggest a future campaign to reduce our hamburger consumption.

Unfortunately, the many stresses on the world’s ecosystems mean that either we eat less meat or change our farming and food manufacturing methods. The greenhouse gas emissions from agriculture, food manufacturing, transport and retailing are now about two tonnes a head, about as much as we can afford to emit from all our activities in 2050. Either we decide to eat a very different diet, as Stern suggests, or we try to change agriculture so that it becomes a helpful part of our drive to reduce emissions. Instead of depleting the soil and abusing animals in pursuit of cheap meat, we could put our weight behind schemes for using agricultural soils to sequester CO2. A new campaign, called Climate Friendly Food, may offer us a way of continuing to eat some meat and looking after the global atmosphere at the same time.



This article was originally published in the Guardian on Tuesday 27 October 2009.

Image source: flourish.org.

A study commissioned by the UK Food Standards Agency concluded that:

there is little, if any, nutritional difference between organic and conventionally produced food and that there is no evidence of additional health benefits from eating organic food.[1]

Yes and no. What the study actually shows is that organic food typically does have higher levels of important nutrients but the high degree of variability in the measured levels means that we cannot be 95% sure that these higher levels are not the outcome of chance. The Food Standards Agency and the report’s authors have misled people interested in this topic and should revise the summaries of their work.

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The FSA study abuses statistics. Let’s take one example. Flavonoids are part of a plant’s defence mechanism against pests. So it is plausible that organically grown fruit and vegetables might contain higher levels because they might have had to protect themselves against insects. Conventionally grown products have the advantage of pesticides and so don’t need to produce flavonoids to the same extent. There’s a reasonable scientific hypothesis that organic foods should contain more flavonoids.

In reasonable doses, flavonoids probably have benefits to human health. When eaten they are excreted quickly but may prompt the presence of higher levels of uric acid in the bloodstream which may help ‘cleanse’ the body of toxic products.

The FSA report looked at 158 experiments that measured the flavonoid content of organic foodstuffs, including strawberries, wine, apples, and tomatoes. On average, these foods contained 38.4% more flavonoids per unit of weight than their conventional equivalents. Whatever you might have read in the press about this study, this means that organic food may well have more flavonoids than conventionally farmed equivalents.

The study denies this for two reasons. First, it removes most of the data from consideration because it doesn’t meet the best standards of scientific research. When the slightly dodgy studies have been taken out, we’re left with only 48 data points. In these cases, the average flavonoid content was only 32.9% higher than the conventional equivalent, down from 38.4% in the wider sample.

The second reason is more important. The high degree of variability in the results means that we can have less than perfect statistical confidence that the organic results really are better. In fact, rather than being 99% statistically certain (the figure for all 158 studies) our confidence falls to 78%. This is principally because some of the surveys of organic fruit or vegetables show a smallish reduction in flavonoid content. Most are much higher, but some are lower. So the careful statistician says that we shouldn’t assume that the average result of a 32.9% increase is truly valid.

I will, if I may, use an analogy to explain this a bit more. Imagine we take a group of 100 20-year-old males and ask them to run one hundred metres. We measure the time taken. Then we ask 100 20-year-old females. On average, the males will be faster. But some females will be faster than some males. So someone looking at the data cannot be absolutely certain that males are, on average, faster than females. But as we increase the number of runners, we are increasingly sure that the average male is genuinely faster than the average female and we are more confident about quantifying the underlying difference. We can do this both because we have a larger number of times but also because we can better measure the underlying variability between males and between females.

In the food study, cutting out the dodgy data cut the number of data points by 70% (so, as it were, we had fewer males and fewer females). And the apparent reliability of the data fell. But, nevertheless, the organic food (the males) was on average significantly better than the conventional food (the females) even though some results (5 out of 48 trials) suggested that conventional food had measurably more flavonoids than organic equivalents.

The result for flavonoids is replicated with the nutrient beta carotene. Beta carotene levels were over 50% higher in the average study, falling to 21% once the slightly dubious studies were extracted. In fact, organic food contains – on average – a higher percentage in 18 out of 23 specific nutrients. It is simply untrue to say, as the FSA does, that organic food contains ‘no difference’ in nutritional content. Organic foodstuffs studied in this work actually contained measurably more nutrients. But the statistical techniques used showed a relatively high probability that this was simply a matter of chance. Few nutrients showed the required 95% confidence level.

If I may, I want to repeat the comment from the FSA press release that I carried in the first few lines:

there is little, if any, nutritional difference between organic and conventionally produced food and that there is no evidence of additional health benefits from eating organic food.

What the FSA should have said is as follows: ‘there appear to be substantial differences in some of the nutritional compounds in organic and conventional foods. But, in most cases, these differences are not great enough to meet the standard statistical requirement of 95% confidence that these differences are not due to chance. The higher apparent availability of some micro-nutrients in organic foods may be very important for human health. Nobody yet knows, certainly not us. We will continue working on this issue rather than publishing conclusions which are not based properly on science or on statistics.’

We can never be truly certain about anything. Science moves ahead by noticing patterns in data and trying to find plausible explanations. And not by baldly stating that because differences are not large or consistent enough, that there can’t be an underlying pattern.

Why is a piece about organic food and nutrition carried on a blog about energy and climate change? Because if we carried the FSA conclusions through to global warming issues, we would be taking no action on climate change. Virtually nothing we think that we know about climate is understood with a confidence exceeding 95%. As denialists are ever fonder of pointing out, 1998 was the hottest year in recorded history. If the FSA was in charge, this would surely mean that we would now be claiming we did not have a sufficiently high level of certainty to want to bother to reduce global emissions.

The fact that the immediate past chair of the FSA, Lord Krebs, now runs part of the UK Climate Change Committee’s activities should therefore make us very nervous.


Footnote
[1] Food Standards Agency, ‘Organic review published’, Wednesday 29 July 2009 http://www.food.gov.uk/news/newsarchive/2009/jul/organic [accessed Wednesday 12 August 2009].



This article was also published on the Guardian Environment Network on Thursday 13 August 2009.