The ability of the Paris Agreement to achieve its ambitious long-term temperature goal depends on mechanisms that can promote a ramp-up of ambitions. Pledge-and-review may facilitate deeper cooperation over time by enhancing trust between parties. It has been proposed that starting out with easier cooperation that entails larger shares of domestic benefits, such as cooperation on short-lived climate pollutants, could also help promote the credibility and trust necessary for the ramping-up of contributions over time. Using a lab experiment we explore how these two mechanisms perform across two stages in a controlled and stylized setting where individual participants face incentives that mirror those of countries deciding on national contributions. We find that starting with easier cooperation does not produce higher levels of trust, and it leads to lower levels of cooperation when cooperation becomes more difficult in stage 2. The pledge-and-review approach does not, in itself, lead to significantly higher levels of cooperation, but it does offset the negative effect of starting with the easy cooperation. It can be seen as a safeguard against failed strategies.

《巴黎协定》实现其雄心勃勃的长期温度目标的能力取决于可以促进雄心壮志的机制。质押与审核可以通过增强双方之间的信任来促进更深层次的合作。有人建议，从更轻松的合作开始，这需要更大份额的国内利益，例如就短期气候污染物开展合作，也可以帮助提高逐渐增加捐款所必需的信誉和信任。通过实验室实验，我们探索了这两种机制在受控和程式化的环境中如何在两个阶段中发挥作用，每个参与者所面对的激励措施都与各国决定国家贡献的激励措施相仿。我们发现，从更轻松的合作开始不会产生更高的信任度，当阶段2中的合作变得更加困难时，它会导致较低的合作水平。质押与审核方法本身并不能带来更高水平的合作，但确实抵消了从简单开始做起的负面影响。合作。可以将其视为防止失败策略的保护措施。