However, that is not to say that numbers aren't important. On the contrary, they are essential. If you want to understand the scope of the problem and evaluate possible solutions, you have to quantify them. Therefore, I'd like to bring numbers into the game at this point by presenting you a link to the website of David MacKay, a Cambridge physics professor who has done some calculations concerning energy supply and demand: www.withouthotair.com . The choice is more or less random - it might not be the ultimate source of information, it's just one that I happen to be aware of. You can download an entire book there for free; if your time is limited, you can start with a 10-page synopsis that's easily readable within less than an hour. That's what I have done. (A cautionary remark: As I haven't had the time to follow his calculations in detail or cross-check with other sources of information, for the time being I'll just trust David MacKay to have gotten the maths right.) The book is focused on Great Britain, but I'd expect the situation in most industrialized nations to be comparable.
Rather than just repeating everything he's writing, I suggest you follow the link and have a look at the material yourself. Let me just extract some key takeaways here as a "teaser":
- We get around 80% of our energy from fossil fuels, which is unsustainable because fossils are limited and may change the climate.
- For any renewable facility to make an appreciable contribution it has to be country-sized.
- We require either a radical reduction in consumption, or significant additional sources of energy – or, of course, both.
- In particular, besides renewables, we probably won't be able to do without one several of the following sources of energy: “clean coal” (i.e. coal power plants equipped with carbon capture and storage technology), nuclear power, and/or renewable energy from other countries (e.g. solar power from the Sahara).
Two points that I personally take out of the synopsis are:
Firstly - anti-dogmatism: nobody really likes the problems that come with nuclear power (radioactive waste, limited supply of uranium, safety of power plants...) and coal (CO2 emissions unless you invest in expensive CCS technology, limited supply of coal). But it may well be that we need to be pragmatic about the use of these sources of energy, simply because we might not be able to do without them in the mid-term future.
Secondly - "If everyone does a little, we'll achieve only a little": If everyone unplugs their mobile phone chargers and turns the TV off rather than leaving it on standby, but continues to drive a Jeep, heat out of his house's single-glass windows, and fly to New York for a shopping weekend every other month, we're not going to get very far in terms of sustainability.
So much for now. This is just a little starting point, and I hope to be able to bring some more quantitative points into this blog in the future, time permitting. For now, I suggest you follow the link above, and hope that you agree with me on the basic message: