Green machine: Fighting the efficiency fallacies
17/8/2010 New Scientist Green machine is our weekly column on the latest advances in environmental technologies.Which is the more effective way to reduce your household’s carbon footprint – turn off lights and appliances when you are not using them, or switch to more energy efficient devices? (Do both - Editor)
Environmental experts say the latter will have a far greater impact on the greenhouse gas emissions that your home is responsible for, but research published this week suggests few of us realise it.
Shahzeen Attari at the Center for Research on Environmental Decisions at Columbia University in New York and colleagues asked volunteers what they considered the best thing they could do to cut their CO2 emissions.
Over half of the 505 people questioned chose steps like turning off lights and gadgets or driving less, while only 12 per cent mentioned more effective efficiency improvements such as swapping incandescent light bulbs for compact fluorescent bulbs, or using more efficient household appliances or cars when renewing.
Some assumptions are perhaps unsurprising, albeit mistaken – people believed that line-drying clothes rather than using a tumble-dryer would save more energy than changing the settings on their washing machine to wash at lower temperatures, for example, although the reverse is actually true.
Mistaken beliefs
Other examples of misunderstandings included the assumption that the energy used to transport goods by truck was roughly the same as by train. In fact trucks consume 10 times more energy per than trains per unit of cargo.
“For small devices and appliances, people have a pretty good understanding of how much energy they use,” says Attari. “However, for large devices they really underestimate the amount of energy they use.”
As a result people underestimated the energy consumed by devices by a factor of nearly three, she says. So when asked to compare moderate energy-consuming devices, respondents correctly identified that desktop computers consume more energy than laptops, but they significantly underestimated the difference.
With households accounting for around one-third of US energy consumption and emissions when personal travel is taken into account, the decisions individuals make can have a huge impact.
Right to fly
Research last year by Thomas Dietz at Michigan State University in East Lansing and colleagues suggests that such behavioural changes could cut household CO2 emissions by 20 per cent, resulting in a 7 per cent drop in overall US emissions.
Efforts to encourage people to cut their energy should emphasise the range of ways that people can do so effectively, says Attari. “We need to go after a variety of different behaviours that consume much more energy,” she says. “Because people might just replace their light bulbs, and feel like they’re off the hook; that they’ve done their part.”
This feeling is even more pronounced when it comes to foreign travel, according to Graham Miller at the University of Surrey in Guildford, UK, and colleagues. When the researchers asked volunteers in the UK about their attitude to sustainable tourism, they found people felt they “deserved the right to fly because they took pro-environmental actions throughout the year”.
The volunteers believed small actions such as reusing plastic bags or changing to low-energy light bulbs would have a greater impact on the environment than changing their holidays. However, The UK government’s 2007 Energy White Paper says holiday air travel is responsible for about 12 per cent of an individual’s CO2 emissions each year.
Journal references: Attari and colleagues, Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1001509107; Dietz and colleagues, Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.0908738106; Miller and colleagues, Annals of Tourism Research, DOI: 10.1016/j.annals.2009.12.002
Go to: http://www.newscientist.com/article/dn19322-green-machine-fighting-the-efficiency-fallacies.html