By Zoe Holliday

I’m not much of an athlete. Don’t get me wrong, I try. But over the past year, my sporting attempts have led to two broken fingers, rope burns behind my knees, and a serious ankle sprain from tripping over my own feet. 

So when I managed to jog a reasonable distance last weekend without either stopping or breaking myself, I felt that I deserved a reward. When I got home, I ate half a bag of cookies and a packet of smarties. Then I realised that by piling on the calories just after burning them off, I had pretty much negated the point of going on the run in the first place. 

Similarly, the intended carbon savings from energy efficiency measures are often not realised in practice, because people spend the money they save on other goods or services that require an energy input. This is the so-called ‘rebound effect.’ The effect was illustrated perfectly in 2009, when Tesco introduced their ‘Turn Lights Into Flights’ campaign – encouraging shoppers to use the clubcard points they earned buying energy saving light bulbs on airmiles. Not a campaign to win over the Guardian readers. 

Pinned to the partition in front of my desk is a postcard with the poster from the Second World War that’s above these words.  I bought it a few years ago because I thought it was amusing from an energy saving perspective. ‘My,’ I thought to myself, ‘how times have changed.’ Turned out to be maybe not so much.

The rebound effect is well-documented (we’ve covered it in previous articles on this blog) and is even taken into account in the Energy Saving Trust’s savings calculations. What is less well documented, however, is the reason why we rebound. But getting to an understanding of these values and motivations will be crucial if we want to minimise the impact of rebound on potential energy savings. 

The most common explanation is simply that increased energy efficiency makes energy cheaper. And if this is the case, then we need to be looking at how we market energy efficiency measures – if we persuade people to act because of financial savings, it should come as no surprise that they want to use their savings on other energy-consuming services. Likewise, if we tell people that their homes will be warmer after installing insulation, it should not be a shock when they turn their thermostat up after the measures have been installed. 

A less well documented theory for the rebound effect is ‘moral self-licensing’ – the idea that by doing something for the environment, people feel ‘morally licensed’ to make less environmental choices in other domains. In a recent study by Verena Tiefenbeck, half of the residents in a 200 block apartment block in Boston were given weekly feedback on their water consumption and how it compared to their neighbours’. As expected, those who received feedback reduced their water consumption by around 7.4% compared to those who did not – but a more surprising result was that these households also increased electricity consumption by 5.7% relative to the control group during this time. 

Interestingly, there is evidence that this moral licensing may even extend outwith the environmental domain. A 2009 study by Nina Mazar and Chen-Bo Zhong suggested that the actual act of purchasing green products may have the counter-intuitive effect of licensing asocial and unethical behaviours. In a series of experiments, Mazar and Zhong showed that after buying green products, participants appeared less willing to share a set amount of money, and were more likely to cheat, lie and steal than those who had bought conventional products. (Maybe this explains the fact that Antony Worrall Thompson, a passionate advocate of organic farming, was recently caught shoplifting?!)

 It’s worth noting that a number of concerns have been raised about the validity of these experiments, as the participants were not actual green consumers and were under lab conditions. But I do believe that if we are to maximise the effectiveness of energy efficiency campaigns (and reduce petty crime), there is a real need to understand what motivates the rebound effect.

In particular, we need to understand that decisions aren’t made in isolation but are shaped by people’s values. If energy saving is marketed by appealing to extrinsic values like popularity, image, conformity or wealth, then it should come as no surprise when they choose to make use of their greater wealth, or to compensate for the fact that they have behaved better than others in one way by self-licensing more indulgent behaviour in another way. 

If we are to counter-act the rebound effect, energy saving messaging needs to convey not extrinsic values but a sense of our moral duty to help meet the climate change challenge and make sure we all have a stable, sustainable future.