One of the obstacles to sustainability can be human nature. Scientists and engineers have a habit of seeing everything as a numbers game. If we reduce the carbon footprint of something by X amount an apply that across the board that will be good….right? Well sometimes not, sometimes such measures can increase pollution by making it easier and cheaper to consume more. We are not factoring in cause and effect.
For example, back during the 80’s it became a bit of trend to install conservatories in houses, either purpose build or retrofitted to existing homes. One of the arguments for this is that by absorbing solar energy in spring and summer, they can reduce the heating bill for the house as well as providing somewhere to grow plants. Similarly, office buildings can use large glazed facades to cut down on heating and lighting costs. And its worth noting that historically, before we had oil fired central heating and electric lighting, many Victorian era homes would have a conservatory for these very reasons.
However, in order to prevent overheating in the summer (and glare from too much sunlight), its important that such areas have shading devices. And in the winter they can get quite cold, so you’ll need to have a way of isolating them from the rest of the house (Victorian houses would often shut off such areas of the house for the winter). However, many modern buildings didn’t have shading devices (so you’d come in to the office and find all the blinds down and the lights on in the middle of the day) or the buildings were open plan, so any energy savings in heating were cancelled out by more energy devoted to cooling in the summer. And some homeowners took to install radiators in their conservatories, effectively increasing their heating bills.
Different types of shading devices, critical if you are using glazed facades in buildings
Energy efficiency improvements haven’t always produced the level of gains expected. For example, we have the effect of low energy light bulbs. While they have reduced electricity demand, but not by as much as was hoped. Why? Because people are more likely to leave light on. Case in point, its daytime while I’m writing this and I’ve just realised the light’s are on in my kitchen, even thought there’s nobody in there. When I was growing up the instruction was that if you were the last person to bed, you turned off all the lights (and there would be hell to pay if you forgot). Now when I’m back home its that you should turn off most of them.
Similarly improvements in building energy efficiency have led to average indoor air temperatures to increase in cold countries and decrease in hotter countries (I remember having to wear a hat to bed in Singapore because it was so cold inside the bedrooms!). And more fuel efficient cars have run hand in hand in an increasing number of driving miles in some countries (thought not always and these increases might be related to other factors such as new roads encouraging driving, or more cars making it less safe to cycle).
My point is, its important to consider the consequences of any action and look at how it may effect patterns of behaviour. Some of these can be positive, e.g. plastic bag taxes very rapidly led to a reduction in plastic bag use. But that’s not always the case (at the same time in the UK that the plastic bag came in, there was a large increase in trolley or shopping basket thefts!). It also serves to highlight that, while energy efficiency is important, on its own it can’t solve the problems of climate change and sustainability. Only by moving away from fossil fuel altogether can these problems be solved.
With sustainability the devil can often be in the detail. Biofuels for example can lower carbon footprints, but this largely depends on how the plants are grown, processed and then transported. Even a slight change in how they are grown, for example draining bog land to create area for the trees (which results in a big pulse of green house gases) or transporting them long distances, can significantly increase the carbon footprint.
With biofuels there can be quite a wide variation in the carbon footprint, which are often governed by very small changes in production methods
We see a similarly issue with alternatives to plastics. On paper by moving away from fossil fuels this can can lower the carbon footprint. But if you are growing material, how is it grown? Does it require fertilisers? (which come from fossil fuels) or climate control (which might also require energy input from fossil fuels). If its much heavier and bulkier that’s going to make it harder to transport (more fossil fuel’s burned). If its harder to mould into shapes compared to plastic (which can be injection moulded), again more waste. And how is it disposed of? If its not recyclable that’s going to be a problem unless we have a means to collect and incinerate it safely (and that incineration process is also going to produce some emissions).
Its here were life cycle analysis is key. This is a process by which engineers can undertake an accounting exercise to work out the carbon footprint of each step of a product’s life cycle, from the extraction of raw materials, its production phase, transportation to customer, its use phase and its end of life (is it recycled, incinerated, or does it go into landfill).
This data not only allows for good decision making, but also tends to highlight where the main issues are. For example, with a car, the main source of carbon emissions is going to be the usage phase when its driven around for hundreds of thousands of miles. Anything you can do to cut this down is generally going to be a good idea, for example by making the car lighter. Even if this pushes up the carbon footprint of the production phase, this will be off-set by lowering the impact of the usage phase. By contrast, in some consumer products it can be either the material production phase or the end of life phase that has the most dramatic impact. This tells engineers where to focus their efforts next in improving the product.
But again, this can have the problem that engineers are working in isolation and not understanding what’s going on in the real world. The cautionary tale of Jatroba is a good example. This appeared (at least on paper) to be an excellent potential source of biofuels with a low carbon footprint (in some cases negative as it helped to lock away greenhouse gases into the soil). It could grow on non-arable land (thus not taking away land from food production), with little need for fertiliser. However, the yields from Jatroba grown under such conditions were low, leading to it being grown on arable land with fossil fuel based fertilisers used to increase its grown rate (largely negating the supposed benefits).
And the switch from meat to vegetarian foods has created a high demand for such foods as asparagus, avacado’s and coconuts, all of which have quite a high carbon footprint and water demand, at least compared to other vegetarian options. While this doesn’t mean that a vegan diet is worse than a meat based one, it again serves to highlight its a trade off, a least worse option. And the benefits are going to depend a lot on how and where its grown, e.g. out of season fruit in green houses (which is then imported long distance by truck or air) is going to be a lot more carbon intensive than fruit grown in season in a field locally.
The problem with climate change and sustainability is that they are very large and complex problems. If there was some easy silver bullet solution it would have been implemented ages ago. There are solutions, but they require a bit more of a complete understanding of what the problem is and how people are likely to react to the proposed solutions.
The life cycle analysis of any product can become quite complicated
This had led some to suggest the solution is to use smart technology. So for example if a driver has a heavy foot (lots of acceleration and heavy braking) the cars computer could be programmed to recognise this and switch to a more energy efficient driving style (so it won’t allow the car to accelerate as quickly, de-rate the engine, and if a hybrid, try to extract as much energy from the braking phase as possible).
Similarly home appliances could be programmed to de-rate at night to reduce energy consumption. If you dial up the thermostat and your home heating system knows you feeling cold has nothing to do with temperature, but instead its the humidity, so it ignores your request and adjusts the humidity instead.
I’d note that this sort of technology is nothing new, its used in aviation where the planes computer is programmed to fly the plane in as fuel efficient and safe a manner as possible, by interpreting the pilot inputs and not necessarily doing exactly what they ask it to do. If the pilots do something they are not supposed to do (e.g. try to pull off a manoeuvre the computer knows would exceed the aircraft’s envelope) the computer will adopt a more moderate response, or even override the pilots completely.
However, I’m not sure how people would react to this. Some might argue its an affront to their freedom (just look at the anti-vaxx / anti-mask brigade). Already there’s a people who have been hoarding incandescent light bulbs or insist on rolling coal. In short we need to appreciate that human nature is as much a part of the climate and sustainability problem as anything else.