The study was conducted by Professor Dr Michael Bechtel, member of the Cluster of Excelence ECONtribute (University of Cologne), Professor Dr Kenneth Scheve (Yale University) and Dr Elisabeth van Lieshout (Stanford University). It has recently been published in Nature Communications.
In representative surveys, the researchers investigated whether the extent to which the public supports costly climate policies, such as introduction of a domestic carbon tax, depends on whether other countries also pursue climate action.
The results suggested that the domestic public is more willing to approve introducing a domestic carbon tax if other countries invest, because individuals expect these policy efforts to be fairer and more likely to be effective.
The team surveyed a total of 10,000 people in Germany, France, the UK and the US in early 2019. Respondents were asked to indicate how much they approved or disapproved of the introduction of a carbon tax. 60 per cent of respondents supported a tax if other countries also introduced one, but approval dropped to 53 per cent when other countries did not join these efforts.
“We also find that when domestic climate measures are embedded internationally, people are more likely to believe that these reforms will have a positive impact on important social, economic and environmental sustainability goals,” said Bechtel.
In a second study, the team investigated whether the costs of climate action would be more broadly accepted domestically if other countries pursued more ambitious and thus more costly measures.
Participants were asked whether they would be willing to support costly climate policy scenarios in which the researchers varied the level of contributions made by other countries. If domestic monthly household costs increased to a higher level, in the case of Germany for example from €39 to €77 per month, support decreased by seven percentage points if the price of carbon dioxide remained low abroad.
However, if other industrialised countries decided to introduce high monthly household costs, domestic policy support only fell by about five percentage points in response to a domestic CO2 price increase.
The team concluded that climate change measures in other countries play a crucial role in securing mass support for domestic climate policy.
“Investing in well-functioning international agreements is worthwhile not only from a natural science perspective, but also for policymakers interested in securing broader public support for costly climate action domestically,” said Bechtel.