On the other hand, stronger income effects are discernible in housing – and particularly mobility. The overall modest effect of income on actual greenhouse gas emissions shows that environmental footprints can be very different within the same income bracket.
This provides room for manoeuvre: better-off households possess considerable scope for avoiding environmental pollution. This is even more effective if there are appropriate incentives for doing so – such as incentive taxes and the promotion of smart and energy-efficient technologies.
Gender also makes a difference: the ecological footprint of women is smaller than that of men. Bruderer Enzler and Diekmann demonstrated this with Ulf Liebe in a supplementary study on electricity consumption using the objectively measured data of an energy supplier. It appears that the electricity use of women in single-person households is almost one quarter lower than that of men living alone. "This difference endures even if one takes into account differences in income and home size," says Diekmann.
Apparent differences between linguistic regions
A comparison with symbolic forms of pro-environmental behaviour shows how important the life cycle analysis of households is: used by many studies for the sake of simplicity, this measures good intentions, such as when recycling, using self-brought shopping bags at the supermarket and other behaviours are gathered into one simple index.
Here, pro-environmental behaviour in German-speaking Switzerland, for example, appears to be considerably better than in the French-speaking Romandy – or Italian-speaking Ticino, come to that. If, on the other hand, one looks at the life cycle analysis of households, which is ultimately the decisive factor, there is no difference between the German-speaking east and French-speaking west of the country.
Yet this conceals significant discrepancies in mobility and housing, which cancel each other out: the environmental impact of mobility in the French-speaking region is higher than in German-speaking Switzerland, while exactly the opposite is true for housing.
What can be done to reduce the ecological impact of households? Every study points to the effectiveness of incentive taxes, says Diekmann. “The reimbursement of payments could even benefit low-income sections of society, since their environmental footprints are smaller than those of better-off households. In addition, there are 'soft' incentives, little psychological 'nudges' whose effectiveness the Environmental Research Group is currently investigating in field experiments with energy suppliers.”