In some ways, thinking about what to do seems easy - to prevent climate catastrophe all we need to do is to reduce CO2. As a goal, reduction of a pollutant seems right. There's more to it though; The basic requirement needs to be broken down into specific steps, for one thing.
So, let's start with pollution reduction. We need to:
- Replace fossil fuel energy sources with renewables.
Well, up to a point. Yes, we certainly need to do this, but it turns out to be unhelpful if we don't also reduce our material needs.
To start with, the type of renewable matters. Biofuels need land. So does food. If we are going to loose land because of rising seas and increasing temperatures we might need to think about what we use the remaining land for.
Come to that, solar and wind farms need land, too. They also need materials to build and install them and provide the necessary infrastructure. This will be a constraint on the speed of deployment.
These various constraints, land use and mined minerals, mean that we may not be, will not be, able to replace all the current energy budget.
With those caveats, we haven't got time to be precious about this. We need more solar, more wave and more wind. And we need to plan for lower energy availability.
- Make things more efficient.
The problem with making things more efficient is that the newly realised savings tend to be used to do more, so the total energy requirement remains the same.
Housing needs to be designed for heating efficiency, but people will leave windows open while the heating is switched on.
Transport needs to be integrated, and transport expectations managed, to avoid increased journey numbers.
Manufacturing needs to be limited in some way to avoid ramped up production.
- Repair, Re-use and Recycle.
Nice alliteration, but it only works with the support of the manufacturers. Goods need to be made so that they can be repaired. Things need to be made to last. Materials used should be recyclable.
This approach should reduce the need to dig stuff up. We might expect the energy needed to make a reparable device, together with the energy needed to make spare parts, to be less than the energy needed to make a non-reparable device multiple times. We might expect the energy needed to extract useful chemicals from a recycling process to be less than that required to mine the source mineral and process that.
Our expectations may not be met in all cases. A certain amount of examination and imagination need to be applied. On the whole though, supporting the three Rs should produce an energy saving.
On the other hand, we should be aware that recycling can never be complete. Objects will not be submitted for recycling, some objects may be so tightly integrated that distinguishing useful materials may be very difficult. For the short term though, (say a few decades), this may not be significant in comparison to the urgency of reducing CO2.
These are commonly known and understood steps, but they feel incomplete. Looking back at the many things that are going wrong we need to consider loss of mineral resources, loss of biodiversity, loss of farmland, social disruption and on and on. To do that we need to move on to a wider and more nuanced set of goals.