What is the rebound effect?

If you're on the Nos Gestes Climat website it means you're already interested in reducing your carbon footprint, so first of all well done!

The two ways to reduce your footprint

No matter which footprint you aim to reduce, there are always two ways to approach it:

• Do less.
• Do better.

All the actions suggested at the end of our calculator end up in one of these two categories: less or better. But are some actions more effective than others?

The risk of "better": the rebound effect

Doing better comes with a risk : the rebound effect, also known as the Jevons paradox (this article explains it in detail). This effect occurs when an increase in consumption offsets the reductions achieved through efficiency gains, due to reduced limitations, constraints or costs. Let’s make it clearer with a few examples:

If you switch from buying all your clothes new to buying second-hand, that’s great. But if this practice leads you to buy more clothes then the overall benefit is greatly less.

If you've made your home insulation better and replaced your old gas boiler with a heat pump, that’s a win. But if, as a result, you increase your heating temperature in winter time, then while the environmental gain remains positive, it is less than initially expected.

If you buy an electric car and the lower environmental and financial cost of each kilometer driven leads you to drive more, then the impact may need to be reconsidered.

The rebound effect is the main challenge facing emissions reductions through technological innovation.

For example, the efficiency gains achieved in internal combustion engine vehicles have been fully offset and even surpassed by the increase in vehicle sales and kilometers driven. Between 1990 and 2005, CO2 emissions from transport in the European Union increased by 25%. The technical improvements were counteracted by:

• The rising number of vehicles.
• Increased vehicle size and comfort, leading to heavier cars (+25% on average between 1990 and 2007).
• More use of air conditioning.
• Moral licensing: since the car pollutes less, people feel justified in driving more.

Less, or truly carbon-free?

The rebound effect is nullified when the increased usage is genuinely and entirely carbon-free and without negative side effects. This, however, is quite rare but not impossible!

If you previously drove 5,000 km per year for short trips and successfully switch to cycling those distances, you can increase your trips without guilt! The footprint associated with bike construction and maintenance is negligible, as a well-maintained bicycle has an almost infinite lifespan. Plus, increased cycling does not have negative side effects like traffic congestion or land use, unlike private cars.

First less, then better

To ensure that your footprint reduction is lasting and not undermined by an unintended rebound effect, prioritize actions that reduce your footprint by doing less: fewer daily kilometers, less meat and animal products in meals, fewer new purchases for your home...

Ideally, once you have reduced your consumption, you can transition the remaining activities to low-carbon alternatives: remaining kilometers covered by bike or electric car, animal products only on special occasions and carefully sourced and new purchases limited to necessities from sustainable providers whenever possible.