After read­ing Cam­bridge physi­cist David MacKay’s much lauded Sus­tain­able Energy (free down­load avail­able), the FT Econ­o­mist Tim Har­ford wor­ries that we are “too com­pla­cent about tech­no­log­i­cal fixes for the twin prob­lems of cli­mate change and finite oil and gas reserves”.

Har­ford sug­gests that if we con­tem­plate the idea that tech­no­log­i­cal progress may not solve these prob­lems, we must there­fore start think­ing real­is­ti­cally about behav­iour shift­ing incentives—specifically, higher car­bon ‘taxes’.

Tech­no­log­i­cal progress and eco­nomic growth loosen the corset of cost-benefit analy­sis, but not the laws of physics. No mat­ter how cheap and effi­cient solar col­lec­tors become, there is only so much solar power avail­able per square metre of land. Hydro­elec­tric energy is con­strained by the quan­tity of rain­fall and the height of reser­voirs above sea level. The most per­fectly designed wind­mill is lim­ited by the energy of the wind. It would barely be pos­si­ble to make the num­bers add up even if renew­able energy gen­er­a­tors were free.

To power a mod­ern coun­try through renew­able energy requires country-scale facil­i­ties. […] Tech­no­log­i­cal progress will be essen­tial but, bar­ring a break­through in nuclear fusion, it will not set us on a path to an energy sys­tem purged of fos­sil fuels.

[…] The chal­lenge is to encour­age the right behav­iour. Cen­trally man­dated efforts will not do the trick, in part because “the right behav­iour” is not a uni­ver­sal constant. […]

Deal­ing with cli­mate change will need many small deci­sions to be made dif­fer­ently. The gov­ern­ment can­not micro­man­age these. This is why a car­bon price, whether set through taxes or emis­sions per­mits, is needed. It is not so much a nudge as a shove in the right direction.

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