This is a reaction to a recent seminar given at the department of Earth Sciences in Göteborg (Sweden). With David's permission, I reprint his comment here:
I enjoyed your recent seminar at the University of Gothenburg - thank you again for your visit. If you recall, a question was asked about what we, as individuals, could do about global warming. You replied along this line: that if you ride your bike to work it would do nothing; if everyone in Sweden rode their bike to work it would do almost nothing, and if everyone in Europe rode their bike it would do a bit more than almost nothing. You also made the comment that what we have to do is develop "alternative energy" sources to the point that people adopt them (instead of building coal power) for economic reasons.
It occurs to me, though, that you missed the potential of the first action to contribute to the second.
Explore the bicycle scenario a little further with me, just as an example of individual actions taken collectively: what if everyone in Europe actually did decide to commute by bicycle? The reduction of direct CO2-emissions might be small, but the socio-economic effects would be enormous. Start with the direct financial effect: cycling is cheap. If people save just $US1 per day, that might total $US60billion per year in Europe. I would guess that the indirect effects would be even larger: you could factor in the savings in health-care (obesity-related costs are 5-6% of EU health-care budget, says Lord Google), infrastructure expenditure, pollution-related costs, traffic congestion-costs etc.
But I'm getting away from my point, which is that if people were to save money by using less energy and then invest it in developing alternative energy, then I think our individual actions could collectively make a big difference. $US60billion/year buys a lot of R&D. For this to work, I expect we would need a government-endorsed and marketed "green bonds"-type scheme for individual investors - I do not think such investment infrastructure is currently in place. Perhaps the first thing we should do as individuals is write to our politicians and demand one?