Like climate change, the possibility of peak oil poses an uncomfortable challenge to citizens and governments alike in the 21st century. ‘Peak oil’ is the term used to describe the point in time at which the worldwide production of crude oil extraction will be maximised. But while it is inevitable that production will peak at some point, it is uncertain when that point will be reached. Peak oil concerns exploded during the rapid escalation of oil prices prior to the 2007 global financial crisis (GFC), and resurfaced recently when oil prices appeared to resume their upward trend. These concerns have been underscored by official bodies such as the International Energy Agency (IEA) warning of a possible ‘supply crunch’ brought about by a lack of new investment following the GFC. The paper suggests that a carbon tax rather than a trading system is the optimal method for pricing carbon, but ultimately the method is not as important as the existence of a price that is relatively uniform across countries and is sufficiently high to materially affect production and consumption decisions, particularly the decision as to whether or not to pursue the development of emission-intensive alternatives to oil. In the medium term, the circumstances created by a price on carbon will likely expand the use of natural gas, both for power generation and transport; in the long term, it is likely to expand the role of electric vehicles and non-fossil forms of power generation. As with climate change, the most cost-effective response to the inevitable but uncertain timing of peak oil is to invest in early adaptation. It will be impossible to redesign cities, switch the vehicle fleet to new forms of fuel and transform the location decisions of producers in a timely manner after the oil supply has peaked. Early investment in adaptation measures will pay high dividends in the future, whether in response to peak oil, climate change or simply better city design and reduced congestion on roads. The paper concludes by suggesting that the peak-oil issue is sufficiently important for regular official re-assessments of the situation to be designed and implemented. If mitigation actions are not planned in advance, the alternative may be for a future where periodic price spikes and shortages affect the nation’s ability to manage the economic cycle by causing the re-emergence of ‘stop-start’ economic conditions such as those experienced in the 1970s.