Effect of reciprocity on public opinion of international climate treaties: experimental evidence from the US and China

This study reports survey results of American and Chinese citizens administered to determine the effect of reciprocity and the absence of reciprocity on public support of international climate treaties. American and Chinese college students and adults were surveyed about their support for signing an international climate treaty including commitments to reduce their greenhouse gas emissions, conditional on the other country signing the same treaty or not. This study finds knowledge of other-country non-support on average decreases cooperative behaviour among all age groups in both the US and China. Knowledge of China’s support for the treaty is found on average to increase support among American adults, while having no noticeable effect on average support among American college students. Chinese citizens are found to not respond positively to reciprocity. Although not statistically significant at conventional significance levels, knowledge of the US’s support is found on average to decrease support among Chinese college students and adults.
Key policy insights
To increase support for international climate treaties, knowledge that another major emitter will sign the treaty does not unanimously increase domestic support.
Knowing the other country will not sign the treaty decreases domestic support for signing an international climate treaty for both Americans and Chinese, relative to not being told about the other country’s decision to sign the treaty.
Knowing China will sign an international climate treaty on average increases American adult support for signing the same treaty, while American college student support is unaffected.
Although not statistically significant at conventional significance levels, knowing the US will sign an international climate treaty on average decreases Chinese support for signing the same treaty.
Policy-makers pursuing increased international support of climate treaties by first getting support from countries with substantial historical emissions might deter international support if little attention to fairness concerns is given.

To increase support for international climate treaties, knowledge that another major emitter will sign the treaty does not unanimously increase domestic support.
Knowing the other country will not sign the treaty decreases domestic support for signing an international climate treaty for both Americans and Chinese, relative to not being told about the other country’s decision to sign the treaty.
Knowing China will sign an international climate treaty on average increases American adult support for signing the same treaty, while American college student support is unaffected.
Although not statistically significant at conventional significance levels, knowing the US will sign an international climate treaty on average decreases Chinese support for signing the same treaty.
Policy-makers pursuing increased international support of climate treaties by first getting support from countries with substantial historical emissions might deter international support if little attention to fairness concerns is given.

本研究报告了针对美国与中国公民开展的调研结果，旨在探究互惠（reciprocity）行为与互惠缺失对公众支持国际气候条约的影响。调研对象涵盖美国与中国的大学生及成年群体，询问他们在对方国家是否签署包含温室气体减排（greenhouse gas emissions）承诺的国际气候条约的条件下，自身对签署该条约的支持意愿。
本研究发现，知晓其他国家的不支持态度，会平均降低中美两国所有年龄群体的合作意愿。研究还发现，知晓中国对该条约的支持态度，会平均提升美国成年群体的支持意愿，但对美国大学生群体的平均支持意愿无显著影响。而中国民众并未对互惠行为产生正向响应；尽管未达到常规显著性水平（conventional significance levels），但知晓美国对该条约的支持态度，会平均降低中国大学生与成年群体的支持意愿。

核心政策洞察
若欲提升国内公众对国际气候条约的支持，知晓另一主要排放国将签署条约，并非总能普遍提升国内公众的支持意愿。
相较于未获悉其他国家签署条约的决策，知晓该国将不签署条约，会同时降低美国与中国民众对签署国际气候条约的国内支持率。
知晓中国将签署国际气候条约，会平均提升美国成年群体对签署该条约的支持意愿，但对美国大学生群体的支持意愿无影响。
尽管未达到常规显著性水平，知晓美国将签署国际气候条约，会平均降低中国民众（含大学生与成年群体）对签署该条约的支持意愿。
试图通过先获取历史排放量较高国家的支持，来提升气候条约的国际支持度的政策制定者（policy-maker），若忽视公平性考量，反而可能削弱国际社会对该条约的支持。

若欲提升国内公众对国际气候条约的支持，知晓另一主要排放国将签署条约，并非总能普遍提升国内公众的支持意愿。
相较于未获悉其他国家签署条约的决策，知晓该国将不签署条约，会同时降低美国与中国民众对签署国际气候条约的国内支持率。
知晓中国将签署国际气候条约，会平均提升美国成年群体对签署该条约的支持意愿，但对美国大学生群体的支持意愿无影响。
尽管未达到常规显著性水平，知晓美国将签署国际气候条约，会平均降低中国民众（含大学生与成年群体）对签署该条约的支持意愿。
试图通过先获取历史排放量较高国家的支持，来提升气候条约的国际支持度的政策制定者，若忽视公平性考量，反而可能削弱国际社会对该条约的支持。