Measuring the impact of scientific consensus on individual preferences for climate change mitigation. A survey experiment

This study investigates the impact of scientific consensus information on public perceptions of climate change and their willingness to pay for mitigation efforts. Utilizing a representative sample of the Italian adult population, participants are randomized into four groups, each exposed to varying statements about the anthropogenic causes of climate change from two scientists with opposing views. Subsequently, participants receive information on the degree of scientific consensus regarding these views. The experiment measures changes in participants' willingness to pay both in income and as an extra cost for consumer goods to mitigate climate change effects. Control variables include political affiliation, education level, and trust in science. Findings provide insights into the effectiveness of consensus messaging in influencing public attitudes towards climate change and policy support.

2024-06-03

2024-06-30

a. Willingness to pay (income tax)
b. Willingness to pay (consumer good price)

a. Willingness to pay (income tax): participants are asked to state a sum (in euro) within the range 0-100 they are willing to pay (as a monthly increase to their income tax) to mitigate the negative effects of climate change.
b. Willingness to pay (consumer good price): participants are asked to state a sum (in euro) within the range 0-1 they are willing to pay as an extra amount to buy a “greener” version of the product whose production has a lower negative effect on climate change.

This study investigates the impact of scientific consensus information on public perceptions of climate change and their willingness to pay for mitigation efforts. Utilizing a representative sample of the Italian adult population, participants are randomized into four groups, each exposed to varying statements about the anthropogenic causes of climate change from two scientists with opposing views. Subsequently, participants receive information on the degree of scientific consensus regarding these views. The experiment measures changes in participants' willingness to pay both in income and as an extra cost for consumer goods to mitigate climate change effects. Control variables include political affiliation, education level, and trust in science. Findings provide insights into the effectiveness of consensus messaging in influencing public attitudes towards climate change and policy support.
• Participants are enrolled in the sample through the SWG panel. The sample will be representative of the Italian adult population.
• Participants in each group will be presented with baseline questions that are the same in all groups. They are then randomized into 4 treatment groups to receive 2 treatments each:

TREATMENT I:
- Participants in all groups receive a general statement about the current climate situation retrieved from the European Environmental Agency report: Global and European Temperatures (2023)
- Group 1 does not receive any additional information
- Group 2 receives a statement about climate change by scientist A who emphasizes the natural causes of climate change
- Group 3 receives a statement about climate change by Scientist B who emphasizes the anthropogenic causes of climate change
- Group 4 receives both statements A and B
- After exposure to the statements, participants will complete a survey questionnaire including post outcome variables.

TREATMENT II:
- Participants in all groups receive a new piece of information about the degree of scientific consensus within the scientific community about the statements they received.
- Group 1 receives information about the degree of the scientific community’s consensus about the main causes of climate change (i.e. anthropogenic vs. natural).
- Group 2 receives information about the degree of the scientific community’s consensus on the position of scientist A as compared to the opposing view
- Group 3 receives information about the degree of the scientific community’s consensus on the position of scientist B as compared to the opposing view
- Group 4 receives information about the degree of the scientific community’s consensus on the positions of both scientists A and B.
- After exposure to this new information participants will complete a new set of questions including outcome variables as after TREATMENT I and new questions to motivate their (potential) change of mind.

• The scientific community consensus is drawn from: Myers, K. F., Doran, P. T., Cook, J., Kotcher, J. E., & Myers, T. A. (2021), "Consensus revisited: quantifying scientific agreement on climate change and climate expertise among Earth scientists 10 years later", Environmental Research Letters 16(10)

randomization done by the external pollster which administers the survey

individuals are randomly assigned to 4 treatment arms, stratified by socio-demographic characteristics

No

4 treatment arms

1600 individuals

400 individuals

Due to financial constraints, the survey experiment will be administered to a maximum of 1600 subject by a professional provider. We devised 4 treatment arms (including control) therefore each arm includes 400 subjects. The MDE for change in WTP induced by treatment is in the range of 0.198 to 0.397 standard deviations (the minimum standard deviation considered is equal to control group average). This MDE further corresponds to a minimum increase of 19.8% increase w.r.t. the average WTP measured in England in a similar survey.