Busting the 'mythbusting'
Jose just sent round [and critiqued] an article from the Times, claiming among other things that driving around is greener than walking. It's a highly irritating article, full of spurious claims based on evaluating one side of an argument carefully but accepting the other unquestioned, but I think the appearance of articles like this is a warning. As a group, we environmentalists are quite bad at communicating with the public, and nonsense like this preys on the irritation and angst we cause.
The problem is due to the kind of people who tend to be environmentalists. In my experience, our camp is divided into two distinct subgroups: the wooly thinkers who act on knee-jerk prejudices and don't evaluate their beliefs, and the real nerds like me who are happy to dive head-first into working out tiny details of the impact of choices we make. Trouble is, neither group's natural mode of thinking is a good strategy for persuading others to change their behaviour.
On many of the issues, the wooly thinkers' instincts lead them to do the right thing, even if they don't understand the reasons (to my mind, the major exceptions are the hysteria around GM foods and wireless electronics). But simply telling people to do X without an explanation is useless at best, and giving incorrect explanations backfires when people realise the explanation was nonsense. This leaves the nerds; a group I understand because I am one. For me, trying to figure out if a change in how I wash the dishes saves water and energy is worthwhile, because I enjoy the intellectual exercise anyway, so there's really no cost. But if I can prove that my special way of doing dishes reduces water consumption by 1%, is it worth trying to convince anyone else to do the same? NO. It's a waste of time and energy that could be spent persuading people to make changes that actually matter, like buying efficient household appliances, and risks putting people off with the message that making a difference is incredibly complicated, when it's really only the last 1% that is.
Unfortunately, we environmentalists are very much to blame for people getting distracted and confused by paper vs plastic. We need to practice much better message control, and keep all the fiddly arguments about details to the more specialist media, where people go looking for them rather than being put off by them. I don't mean to suggest that such arguments should be dropped or had in secret-those are recipes for giving wrong advice and/or making everyone not party to the discussion deeply suspicious-but we need to present a clear, well-reasoned but simple story, which doesn't call for unrealistic individual sacrifices, to people not inclined to get stuck in the details. For those who are interested in details, we have excellent places like Grist's Ask Umbra advice column and Sightline's "wonktastic" blog. For the daily papers and the teevee, we need to focus on advice people can use.
Now, back to the actual claims in the obnoxious article that triggered this post. I'm feeling pedantic enough to write about each one, but I don't have the time to source everything properly. If you find anything below dubious, ask about in the comments and I'll dig up references when I have the time.
“Driving a typical UK car for 3 miles [4.8km] adds about 0.9 kg [2lb] of CO2 to the atmosphere,” he said, a calculation based on the Government’s official fuel emission figures. “If you walked instead, it would use about 180 calories. You’d need about 100g of beef to replace those calories, resulting in 3.6kg of emissions, or four times as much as driving.
update: Clark Williams-Derry @ Sightline has analysed this claim, and and found it to be even further from the truth than I had realised.
Jose pointed out the following
- it assumes that we don't have excess calories in our diets and would need to replace them if we walked
- it assumes that we must replace those calories with high-cost (resource-wise) foods like beef
- it ignores the true costs of building those cars and producing that petrol
To which I would add that it falsely assumes we'd go to the same shops on foot as by car, when much of the advantage of travelling under one's own power is that it encourages people to use local services. Also, beef is the environmentally worst option for additional calories, and I seem to recall that the typical car uses about as much energy in its manufacture and delivery as in its use. Not to mention the environmental impacts of medical care, which is less often necessary among people who get enough exercise....
"Three quarters of supermarkets’ energy is to refrigerate and freeze food prepared elsewhere."
This may be true, but how much food would be wasted otherwise? Now there is a solution to this, for people who have the luxury of being able to shop daily, and that's to buy fruit and vegetables every day or two, from local markets, in which case they'll keep without refrigeration. I get to do this because I happen to walk past Pike Place Market on the way to and from work, but it's simply not realistic advice for most people.
Traditional nappies [diapers, for Americans] are as bad as disposables, a study by the Environment Agency found. While throwaway nappies make up 0.1 per cent of landfill waste, the cloth variety are a waste of energy, clean water and detergent
OK, but what resources go into manufacturing the disposable nappies? How much oil (for the synthetic fibres), energy and chlorine bleach? Not to mention water-almost all industrial processes use a lot of water for some purpose or other-and transport fuels in getting them from the factory to the customer. It is extremely rare for disposable anything to be an environmental win.
Paper bags cause more global warming than plastic. They need much more space to store so require extra energy to transport them from manufacturers to shops
The transport of paper bags is a net loss, for exactly the reason they suggest. But what about their manufacture? And recycling - recycling saves large amounts of energy relative to using new materials, and paper bags are much more likely to get recycled because they can go into the standard recycling stream anywhere that recycles its waste at all. Plastic bags can be a problem for the machines that sort recyclables, so where they get recycled at all they often have to be collected separately, and once recycling becomes a hassle most people stop doing it. And besides, the biggest reason not to use plastic bags is what happens to them if they neither end up recycled nor in a landfill: they never go away.
Diesel trains in rural Britain are more polluting than 4x4 vehicles. Douglas Alexander, when Transport Secretary, said: “If ten or fewer people travel in a Sprinter [train], it would be less environmentally damaging to give them each a Land Rover Freelander and tell them to drive”
Right. But how often are those trains that empty? I have never seen it. If he's talking specifically about the last trip of the day, what's the average number of passengers on that route through the day? Sometimes almost-empty buses and trains are worth running as a kind of 'loss leader' that persuades the rush hour commuters to use public transport, because they know that they're not sacrificing the option of staying out later than planned, unlike someone who relies on the maddeningly limited train service round here. Sometimes it really is a net loss to be running fixed-schedule public transport, but then there are still better solutions than single-occupancy cars. In that situation, it is both less polluting and cheaper to shut down the train route and replace it with a dial-a-ride service or something like King County's brilliant vanpool system. But it's completely fallacious to go from the fact that some train services are a bad idea to the generalisation about "Diesel trains in rural Britain" as if it applies in every case.
Burning wood for fuel is better for the environment than recycling it, the Department for Environment, Food and Rural Affairs discovered
This one is probably true, if and only if the wood being burned is replacing other fossil fuel use. If you replace a coal fire with one that burns waste paper and wood, everyone wins (especially you because your home gets less toxic). But if you have an electric heater powered by wind, and you replace that with wood burning... not so good. It's a huge leap to go from "this can be better in some cases" to "burning your waste wood is good". And then there's the issue of the local pollution produced if everyone in a big city heated their houses by burning wood.
Organic dairy cows are worse for the climate. They produce less milk so their methane emissions per litre are higher
Less milk per unit of what? It sounds like they mean less milk per cow, and have completely skipped evaluating the greenhouse gas output of feeding that cow. Bear in mind that many fertilisers are fossil fuel derived in themselves, and huge amounts of energy goes into the manufacture of agrochemicals. Then there's the fuel for crop-spraying aircraft, the likelihood that the non-organic cows' fodder has been trucked in from far away, and so on....
Someone who installs a “green” lightbulb undoes a year’s worth of energy-saving by buying two bags of imported veg, as so much carbon is wasted flying the food to Britain
This may be true, but only because replacing a solitary light bulb is such a small step. My 1000-square-foot home has 18 light fixtures, several of which take several bulbs. And even so lighting makes up a pretty small proportion of the electricity bill. Doesn't mean that replacing the crappy incandescent bulbs with energy-efficient ones wasn't worth it, but it was worth doing because it was an easy step that costs nothing (actually it pays for itself after 4 months of continuous use at local, cheaper-than-most-places electricity rates, and starts saving me money after that) and at least has some environmental benefit.
Trees, regarded as shields against global warming because they absorb carbon, were found by German scientists to be major producers of methane, a much more harmful greenhouse gas
This one I know absolutely nothing about, but I'm immediately skeptical because I smell bad science reporting. Where's the reference? "German scientists" does not help me find the source and evaluate it. And how much methane do they produce? Without some numbers or at least a comparison, I can't tell whether we should cut down every tree on earth or completely ignore this study because the problem it points out is trivial in comparison to the good done by trees.
update: a commenter tracked down the source and some commentary on it, and it sounds like the methane emissions are real, but their impact is dwarfed by trees' carbon absorption.
*sigh* I spent too long on that. It does make an overall point though, which is that environmental science is complicated, and selective use of evidence can 'prove' almost anything. When we get carried away arguing about whose narrow path is the holiest, all we're doing is leaving a door open for bad journalism that takes advantage of this to confuse and discourage people who want to do the right thing.
The problem is due to the kind of people who tend to be environmentalists. In my experience, our camp is divided into two distinct subgroups: the wooly thinkers who act on knee-jerk prejudices and don't evaluate their beliefs, and the real nerds like me who are happy to dive head-first into working out tiny details of the impact of choices we make. Trouble is, neither group's natural mode of thinking is a good strategy for persuading others to change their behaviour.
On many of the issues, the wooly thinkers' instincts lead them to do the right thing, even if they don't understand the reasons (to my mind, the major exceptions are the hysteria around GM foods and wireless electronics). But simply telling people to do X without an explanation is useless at best, and giving incorrect explanations backfires when people realise the explanation was nonsense. This leaves the nerds; a group I understand because I am one. For me, trying to figure out if a change in how I wash the dishes saves water and energy is worthwhile, because I enjoy the intellectual exercise anyway, so there's really no cost. But if I can prove that my special way of doing dishes reduces water consumption by 1%, is it worth trying to convince anyone else to do the same? NO. It's a waste of time and energy that could be spent persuading people to make changes that actually matter, like buying efficient household appliances, and risks putting people off with the message that making a difference is incredibly complicated, when it's really only the last 1% that is.
Unfortunately, we environmentalists are very much to blame for people getting distracted and confused by paper vs plastic. We need to practice much better message control, and keep all the fiddly arguments about details to the more specialist media, where people go looking for them rather than being put off by them. I don't mean to suggest that such arguments should be dropped or had in secret-those are recipes for giving wrong advice and/or making everyone not party to the discussion deeply suspicious-but we need to present a clear, well-reasoned but simple story, which doesn't call for unrealistic individual sacrifices, to people not inclined to get stuck in the details. For those who are interested in details, we have excellent places like Grist's Ask Umbra advice column and Sightline's "wonktastic" blog. For the daily papers and the teevee, we need to focus on advice people can use.
Now, back to the actual claims in the obnoxious article that triggered this post. I'm feeling pedantic enough to write about each one, but I don't have the time to source everything properly. If you find anything below dubious, ask about in the comments and I'll dig up references when I have the time.
“Driving a typical UK car for 3 miles [4.8km] adds about 0.9 kg [2lb] of CO2 to the atmosphere,” he said, a calculation based on the Government’s official fuel emission figures. “If you walked instead, it would use about 180 calories. You’d need about 100g of beef to replace those calories, resulting in 3.6kg of emissions, or four times as much as driving.
update: Clark Williams-Derry @ Sightline has analysed this claim, and and found it to be even further from the truth than I had realised.
Jose pointed out the following
- it assumes that we don't have excess calories in our diets and would need to replace them if we walked
- it assumes that we must replace those calories with high-cost (resource-wise) foods like beef
- it ignores the true costs of building those cars and producing that petrol
To which I would add that it falsely assumes we'd go to the same shops on foot as by car, when much of the advantage of travelling under one's own power is that it encourages people to use local services. Also, beef is the environmentally worst option for additional calories, and I seem to recall that the typical car uses about as much energy in its manufacture and delivery as in its use. Not to mention the environmental impacts of medical care, which is less often necessary among people who get enough exercise....
"Three quarters of supermarkets’ energy is to refrigerate and freeze food prepared elsewhere."
This may be true, but how much food would be wasted otherwise? Now there is a solution to this, for people who have the luxury of being able to shop daily, and that's to buy fruit and vegetables every day or two, from local markets, in which case they'll keep without refrigeration. I get to do this because I happen to walk past Pike Place Market on the way to and from work, but it's simply not realistic advice for most people.
Traditional nappies [diapers, for Americans] are as bad as disposables, a study by the Environment Agency found. While throwaway nappies make up 0.1 per cent of landfill waste, the cloth variety are a waste of energy, clean water and detergent
OK, but what resources go into manufacturing the disposable nappies? How much oil (for the synthetic fibres), energy and chlorine bleach? Not to mention water-almost all industrial processes use a lot of water for some purpose or other-and transport fuels in getting them from the factory to the customer. It is extremely rare for disposable anything to be an environmental win.
Paper bags cause more global warming than plastic. They need much more space to store so require extra energy to transport them from manufacturers to shops
The transport of paper bags is a net loss, for exactly the reason they suggest. But what about their manufacture? And recycling - recycling saves large amounts of energy relative to using new materials, and paper bags are much more likely to get recycled because they can go into the standard recycling stream anywhere that recycles its waste at all. Plastic bags can be a problem for the machines that sort recyclables, so where they get recycled at all they often have to be collected separately, and once recycling becomes a hassle most people stop doing it. And besides, the biggest reason not to use plastic bags is what happens to them if they neither end up recycled nor in a landfill: they never go away.
Diesel trains in rural Britain are more polluting than 4x4 vehicles. Douglas Alexander, when Transport Secretary, said: “If ten or fewer people travel in a Sprinter [train], it would be less environmentally damaging to give them each a Land Rover Freelander and tell them to drive”
Right. But how often are those trains that empty? I have never seen it. If he's talking specifically about the last trip of the day, what's the average number of passengers on that route through the day? Sometimes almost-empty buses and trains are worth running as a kind of 'loss leader' that persuades the rush hour commuters to use public transport, because they know that they're not sacrificing the option of staying out later than planned, unlike someone who relies on the maddeningly limited train service round here. Sometimes it really is a net loss to be running fixed-schedule public transport, but then there are still better solutions than single-occupancy cars. In that situation, it is both less polluting and cheaper to shut down the train route and replace it with a dial-a-ride service or something like King County's brilliant vanpool system. But it's completely fallacious to go from the fact that some train services are a bad idea to the generalisation about "Diesel trains in rural Britain" as if it applies in every case.
Burning wood for fuel is better for the environment than recycling it, the Department for Environment, Food and Rural Affairs discovered
This one is probably true, if and only if the wood being burned is replacing other fossil fuel use. If you replace a coal fire with one that burns waste paper and wood, everyone wins (especially you because your home gets less toxic). But if you have an electric heater powered by wind, and you replace that with wood burning... not so good. It's a huge leap to go from "this can be better in some cases" to "burning your waste wood is good". And then there's the issue of the local pollution produced if everyone in a big city heated their houses by burning wood.
Organic dairy cows are worse for the climate. They produce less milk so their methane emissions per litre are higher
Less milk per unit of what? It sounds like they mean less milk per cow, and have completely skipped evaluating the greenhouse gas output of feeding that cow. Bear in mind that many fertilisers are fossil fuel derived in themselves, and huge amounts of energy goes into the manufacture of agrochemicals. Then there's the fuel for crop-spraying aircraft, the likelihood that the non-organic cows' fodder has been trucked in from far away, and so on....
Someone who installs a “green” lightbulb undoes a year’s worth of energy-saving by buying two bags of imported veg, as so much carbon is wasted flying the food to Britain
This may be true, but only because replacing a solitary light bulb is such a small step. My 1000-square-foot home has 18 light fixtures, several of which take several bulbs. And even so lighting makes up a pretty small proportion of the electricity bill. Doesn't mean that replacing the crappy incandescent bulbs with energy-efficient ones wasn't worth it, but it was worth doing because it was an easy step that costs nothing (actually it pays for itself after 4 months of continuous use at local, cheaper-than-most-places electricity rates, and starts saving me money after that) and at least has some environmental benefit.
Trees, regarded as shields against global warming because they absorb carbon, were found by German scientists to be major producers of methane, a much more harmful greenhouse gas
This one I know absolutely nothing about, but I'm immediately skeptical because I smell bad science reporting. Where's the reference? "German scientists" does not help me find the source and evaluate it. And how much methane do they produce? Without some numbers or at least a comparison, I can't tell whether we should cut down every tree on earth or completely ignore this study because the problem it points out is trivial in comparison to the good done by trees.
update: a commenter tracked down the source and some commentary on it, and it sounds like the methane emissions are real, but their impact is dwarfed by trees' carbon absorption.
*sigh* I spent too long on that. It does make an overall point though, which is that environmental science is complicated, and selective use of evidence can 'prove' almost anything. When we get carried away arguing about whose narrow path is the holiest, all we're doing is leaving a door open for bad journalism that takes advantage of this to confuse and discourage people who want to do the right thing.