Why carbon savings don't always match the forecasts
People who shop on the web or work from home could be increasing carbon emissions rather than helping to reduce them, according to a new report from the Institution of Engineering and Technology (IET).
Unless online shoppers order more than 25 items, the impact on the environment is worse than traditional shopping, the study finds, while working from home increases home energy use by as much as 30 per cent, and can lead to people moving further from the workplace, stretching urban sprawl and increasing pollution.
The report's authors look at the 'rebound' effects, the unintended consequences of implementing new technologies and policies that mean real energy savings don't match up to the forecasts.
Some studies estimate that energy saved as a result of working from home may be as low as one per cent when rebound effects are taken into account.
Environmental savings can be achieved if online shopping replaces 3.5 trips to the shops, or if 25 orders are delivered at the same time, or if the distance travelled to where the purchase is made is more than 50km. Shopping online does not offer net environmental benefits unless these criteria are met.
The size of the rebound effect needs to be considered when making policy decisions. "If the rebound effect is large from a technology, then interventions such as pricing strategies become more effective compared to technology standards," the authors say.
Professor Phil Blythe, chair of the IET Transport Policy Panel, which produced the report, said: "We hear a lot about the environmental benefits achieved as a result of working from home. However, on closer inspection it does appear that any environmental benefits are negated.
"Our report highlights two important messages for policy makers. Firstly, climate change is a real threat to our planet, so we must not get overwhelmed by the task and use rebound effects as an excuse not to act.
"Secondly, policy makers must do their homework to ensure that rebound effects do not negate the positive benefits of their policy initiatives and simply move carbon emissions from one sector to another."
'Rebound: Unintended consequences from transport policies and technology innovations' can be downloaded from the IET website.