Conference Agenda

We investigate the causal effect of comparative feedback, i.e., information indicating how an individual’s carbon footprint compares to others’, on costly mitigation efforts. In particular, we consider individuals’ beliefs about their relative carbon footprint (i.e. their positions in the national distribution) as a source of heterogeneity. Using a survey experiment with a nationally representative sample from Germany, we calculate respondents’ carbon footprints based on the most emitting activities and elicit their beliefs about their relative carbon footprint via an incentivized task. A randomly selected subset of respondents then receives comparative feedback. We measure the effect of comparative feedback on respondents’ mitigation efforts. Our results show that nearly two-thirds of the respondents are subject to optimistic bias, i.e., they underestimate their relative carbon footprints. Moreover, while we find no effect of comparative feedback on the full sample, its effects vary by respondents’ relative carbon footprints and the direction of the bias. Respondents for whom comparative feedback conveys a positive signal of their prosociality—because they learn that their relative carbon footprints are small, smaller than they believed, or both—reinforce their mitigation efforts. Instead, respondents for whom comparative feedback conveys a negative signal of their prosociality—because they learn that their relative carbon footprints are large, larger than they believed, or both—reduce their mitigation efforts or do not change them. These contrasting responses result in a “divergence from the mean”, deviating from the “regression towards the mean” that is typically observed in studies of social norms and pro-environmental behavior.

This study explores the impact of informational interventions on individuals’ private and public climate actions. Addressing the phenomenon of pluralistic ignorance (individuals’ misperception of others’ support for climate policies), we conducted an online experiment with US participants, testing whether providing accurate information about public support for carbon taxation influences climate action. Results reveal that while such information reduced misperceptions, it marginally, though not statistically significantly, reduced private climate action, measured by donations to an organization lobbying for climate policies. The intervention did not affect the behavior of those who underestimated the actual support for carbon taxation but negatively impacted the donation decisions of those who overestimated support, suggesting a boomerang effect. The intervention increased public climate action, measured by the minimum reward required to attend climate policy discussions with peers.

We present the results of a series of public-bad laboratory experiments in which we test whether an informative message of suggested behavior with an implicit moral appeal, and a tax that is insufficient to induce the optimal level of the externality, can complement each other when implemented jointly, or not, and by how much. Our results confirm that the average subject, (a) behaves consistently with having moral preferences, (b) is “nudgeable” by such a such a message, (c) exhibits preferences that are non-separable from the choice of a tax as instrument (the tax crowds-out part of its moral preferences). Additionally, when comparing the relative effects of both instruments, we find that the tax has a greater impact on reducing the externality than the nudge, even though the tax was only half of what would be needed to reach the socially optimal level. More interestingly, we find a negative synergy between the tax and the nudge when implemented together, and that this negative synergy is stronger for those subjects that are more nudgeable. These results challenge the policy recommendation that nudges can effectively complement low taxes while awaiting the political will to raise them.

This paper investigates the effects of environmental lobbying on international trade

in waste. We first develop a direct lobbying framework à la Grossman and Helpman

(1994) that emphasizes the potential impact of green lobbies on the environmental policy and how North-to-South waste flows are affected through this policy channel. We show that the politically chosen policies are ambiguous relative to the socially optimal levels, depending on the heterogeneity of environmental preferences and the degree of pollution damages from waste. This in turn leads to ambiguous effects of environmental lobbying on the North-to-South waste trade. Further, we build an indirect lobbying model based on Yu (2005) to analyze the impact of indirect lobbying through public persuasion by interest groups on environmental policy stringency, political contributions and waste exports. We show that strengthening green lobbying induces the substitution of direct and indirect competition from both lobby groups if and only if when the size of the capitalists and the waste-induced pollution damages are small enough. In this case, environmental lobbies are less aggressive indirectly but behave more aggressively directly, while the converse holds for the capitalist lobbies. This leads to a more stringent environmental

policy and more waste to be exported. Surprisingly, we also find that an increase in the waste disposal fee in the South leads to more competition both directly and indirectly.