On the difficulty of environmental micro optimisation

When it comes to things that a person can do to help reduce the negative environmental impact of their life, I think one of possible several sensible distinctions to draw is one between what I call "environmental macro optimisations" and "environmental micro optimisations".

Macro optimisations are big, expensive, obvious changes that have an incontrovertibly positive impact on the environment. Powering your house using solar panels on the roof, installing rainwater tanks and driving an electric car are all good examples of macro optimisations. Micro optimisations are much smaller, cheaper, simpler changes that don't have quite so much of an effect: taking a re-usable mug with you to the coffee shop instead of using a plastic disposable, for example.

It's easy to think of micro optimisations as not being worth the effort, but I think they are. They may not individually have as much impact as macro optimisations, but it's easier to get them adopted on a larger scale. Getting 50% of the population to practice one or two good micro optimisations might be more achievable than getting 10% to practice a macro optimisation, and have just as much good effect. The really serious problem with micro-optimisations is that they're actually quite hard to get right, and - worse - few people seem to realise it. Gut instincts and common knowledge can often lead you astray. In fact, if you didn't bat an eyelid at my coffee cup example earlier, you've already fallen victim to this.

Most people seem to take it for granted that taking a re-usable ceramic or metal cup to the coffee shop is better for the environment than using a plastic or styrofoam disposable cup each time, but as this article discusses, the disposables end up being better. Reusable mugs require a lot more energy to manufacture than a simple injection molded disposable, and having to clean them many times during their life uses up a whole lot of water (which takes energy to heat) and potentially nasty dishwashing chemicals.

Most people seem to take it for granted that using re-usable cloth nappies are better for the environment than nasty disposable plastic nappies, but as this article discusses, this issue is tremendously controversial. Whether or not the extra energy and resources required to produce a never ending supply of disposable plastic nappies is cancelled out by the extra energy and resources required to constantly clean cloth nappies depends on the details of washing machine efficiency, which changes all the time. Which option is best for you depends largely on how modern your washing machine is.

Most people seem to take it for granted that riding a motorbike or scooter is better for the environment than driving a car, but as this article discusses, they're actually probably worse. While motorbikes are much smaller and lighter than cars, and hence burn a lot less petrol to cover the same distance, their lower cost and looser regulations mean that what fuel they do burn they burn much less cleanly, making them worse over all.

The point, in case you haven't got it yet, is that micro optimisation is hard. Doing what feels obviously right, or doing what everyone else is dong, often ends up doing more harm than good. A rational environmentalist can't afford to be lazy when making micro-optimisations. Every decision needs to be researched. The core of the matter seems to be that to get things right, one has to consider very many aspects of a micro optimisation choice. It's insufficient to reason "this approach produces less landfill, so it's better" or "this approach uses less petrol/electricity/water, so it's better". Very often you can only improve one aspect by making another one worse, so you need to consider them all. Also, you can't just think in the now, you need to take a "cradle to grave" view of all your options. There are two major problems with this.

First of all, the average person has neither the understanding nor the access to data to accurately assess these various impacts. To do the job properly you have to know all sorts of details about every step in a lot of processes - how things are manufactured, how they are transported, how they are disposed of, how power is generated, water is collected, etc. Even the average holder of a Bachelor of Engineering isn't going to know all the stuff needed to do these calculations off the top of their head.

Second of all, even if the average person could easily figure out exactly how much landfill, how much CO2, how much plastic, how much water, etc. a particular choice required, there is still the problem of how to prioritise these things. To phrase this in terms of mathematical optimization (which is the correct way to think about it), we have the problem of not actually knowing exactly what our objective function is. Is it worth consuming x extra cubic metres of landfill per year in order to produce y less tons of CO2? Using z extra kilograms of plastic to save w megalitres of water? Which of these concerns is more important? It's unlikely that these questions even have clear, static, objective answers. It depends on where you live, it depends on possibly unreliable estimates of how much of various resources exist it nature, and it depends on which of a number of possible environmental catastrophes you think is worse.

Is environmental optimisation a matter of "go hard or go home"? Perhaps not entirely, but it seems likely to me that until some people somewhere make a tremendous effort to actually do all the terribly complicated mathematics required to clear all these issues up for common choices, people who want to be rational environmentalists should probably refrain from getting too caught up in micro optimisations that shift the balance amongst things they consume, and focus instead on just consuming less. Instead of agonising over whether to drive a petrol car or a motorbike, ask yourself if you can get away with just doing less driving. Instead of worrying about what sort of container to buy a drink in when you're out, try to just buy less drinks when out.

Finally, this entry is perhaps overly pessimistic. Environmental micro-optimisation isn't all doom and gloom, and there are small things one can do which are obviously helpful. Hanging your laundry out to dry when the weather permits instead of using an electric drier is obviously a good thing to do. The important take away message is that you need to think about your micro optimisations and whether they actually, clearly help, or whether they're just trading one problem for another problem without actually having any clear benefit.