How do you build climate support
Can exposing ordinary citizens to financial market participation in energy-sector stocks, rather than direct informational or persuasion campaigns, causally increase support for climate mitigation policies? Does the type of asset (green vs. brown) or the presence of real financial stakes, matter for this effect? This is the question Michelle Hanlon, Saumitra Jha, Namrata Kala, Nemit Shroff, and Chagai M. Weiss are analyzing in this paper.
The authors ran a pre-registered RCT with 3,806 U.S. adults fielded around the 2024 presidential election. Participants completed a baseline climate attitudes survey, then 2,406 were randomly assigned a real financial portfolio of either green (solar) or brown (fossil-fuel) energy stocks worth $50–$100 and invited to track and trade assets over six weeks. Climate beliefs and behaviors were measured at midline, endline, and eight months post-treatment via entirely separate, anonymous surveys to eliminate social desirability bias, and aggregated into a composite Climate Action Support Index (CASI). The control group (n = 1,400) received no portfolio but completed all surveys, enabling clean causal identification.
Findings
Primary treatment effect:
Financial exposure raised the CASI by 0.065 standard deviations by endline , nearly doubling the midline effect of 0.036 SD and consistent with learning accumulating over time.
Green vs. brown portfolios:
Both green and brown asset holders increased climate support, ruling out motivated reasoning as the main channel.
Climate skeptics:
Effects were significantly larger for participants with below-median baseline climate support, meaning the intervention expanded the pro-climate coalition rather than just reinforcing existing believers.
Durability:
Support persisted eight months post-divestment, a level of durability rarely achieved by messaging-based interventions.
Mechanism — learning:
- Treated respondents shifted media consumption away from polarized sources and toward financial news.
- They became more accurate at predicting the environmental impact (carbon emissions) of firms in the study.
- Overall financial literacy increased in the treatment group.
Bottom line: Giving people a modest financial stake in energy-sector stocks, regardless of whether those stocks are green or brown, induces organic learning about climate change and its economic implications, producing durable support for climate action, especially among those initially most skeptical.
Seeing Green: The Effects of Financial Exposures on Support for Climate Action
Authors: Michelle Hanlon, Saumitra Jha, Namrata Kala, Nemit Shroff, Chagai M. Weiss
From: MIT Sloan, Stanford GSB, University of Toronto
Why voters prefer bad climate policy
Why do voters consistently prefer cost-ineffective environmental standards over economically superior market-based instruments like carbon taxes and cap-and-trade? Does limited economic literacy explain this? This is the question addressed in this paper by Chenxi Jiang, Maximiliano Lauletta, Ro’ee Levy,Joseph S. Shapiro, and Dmitry Taubinsky.
The authors ran parallel survey experiments on a nationally representative U.S. sample (AmeriSpeak, n = 1,817) and a convenience sample (Prolific, n = 1,899), benchmarked against 292 expert environmental economists. Participants read descriptions of four policy instruments and rated their support and beliefs. One-third were randomly shown a short video on tax incidence, one-third on allocative efficiency, and one-third served as controls. A follow-up auxiliary survey ruled out experimenter demand effects. Results were interpreted through a calibrated political economy model linking voter literacy to instrument choice.
Findings
On preferences:
- Only 14% of the representative sample support consumer carbon taxes, compared to 30% for emission standards; 50% rank standards first overall.
- Respondents prefer stricter policy under standards but weaker policy under market-based instruments, creating a trade-off between cost-effectiveness and political feasibility.
On beliefs:
- The general public believes market-based instruments raise energy bills more than standards, the opposite of what expert economists believe.
- They also fail to see that a producer tax passes through to consumers the same way a consumer tax does (misunderstanding tax incidence).
On treatment effects:
- The pass-through video made support for consumer and producer taxes more similar, moving beliefs closer to expert views.
- The allocative efficiency video increased relative support for market-based instruments over standards, though effects were more heterogeneous across populations.
Theoretical contribution:
A political economy model shows that with economically literate voters, a planner always chooses a market-based instrument (though political constraints push it below the Pigouvian optimum). With sufficiently illiterate voters, the planner is flipped to choosing an inefficient standard, because it clears the political feasibility constraint.
Understanding Support for Cost-Ineffective Environmental Policy Instruments
Authors: Chenxi Jiang, Maximiliano Lauletta, Ro’ee Levy,Joseph S. Shapiro, Dmitry Taubinsky
From: MIT, Federal Reserve Board, Tel Aviv University, UC Berkeley
