Insulation is still top of the list. It saves money overall as well as saving on emissions. Other than dropping beef from your diet it's the cheapest and best way to reduce emissions.
Should we be banning beef instead?
This assumes we can make a difference as individuals, which is a problematic idea.
The lockdowns we saw worldwide resulted in huge reductions in car & plane use. The economy took a hit and we only saw a 7% drop in greenhouse gas emissions from all of those quiet roads.
Now imagine the UK went ahead and insulated far more than it currently is. What would happen? Well, we would save a bit on gas (good), but many would just have warmer homes. Those that did save gas, would save that money, and likely spend it elsewhere, resulting in a benefit for the economy. This can actually cause more emissions, espeically if people are buying stuff (likely made in Asisa) or jettig off on holidays. Even if they put the money in the bank, the bank would invest it elsewhere, which again is good for economic growth.
This is Jevons Paradox at work, and why focussing on efficiency is wrong headed. Yes, this can be countered by carbon taxes, but what really makes a difference is:
Greening the economy. Measure the economy not by GDP, but by a doughnut chart to measure our standard of living against the impact on the planet. This is a real challenge, and we don't have all the answers yet of how to do this fully (see the book Doughnut Economics).
Also, we need to focus on the big emitters, as they are responsible for the bulk of emissions. So fossil fuel companies, steel and concrete production, and glass.
Steel: Invest in alternative to coke for virgin steel (current contender in hydrogen)
Concrete: Some way to go yet:
https://www.imperial.ac.uk/news/221654/best-ways-carbon-emissions-from-cement/
Food: Low meat diet is better than a vegetarian one. We may end up with vertical farming, but we're a long way from it in the UK. But also remember we still fly in things like asparagas, and grow things in carbon emitting greenhouse when it would be better to import from Spain. We also need to learn to put more carbon into the soil, as part of the food chain.
Electricity: Renewables and nuclear in high abundance. We need to reprocess nuclear fuel, and close down more coal plants worldwide.
Air travel: We have to go biomass for this. Short haul maybe able to go electric though.
Insulation is something people can feel they are making a difference, and may even improve some people's lives, but will make little difference to climate change generally.
Sorry, all very broad strokes for brevity. Went off on one there.
