The increase in global temperatures requires substantial reductions in the greenhouse emissions from consumer choices. We use an experimental incentive-compatible online supermarket to analyse the effect of a carbon-based choice architecture, which presents commodities to customers in high, medium and low carbon footprint groups, in reducing the carbon footprints of grocery baskets. We relate this choice architecture to two other policy interventions: a bonus-malus carbon tax on all grocery products; and moral goal priming, using an online banner noting the moral importance of reducing one’s carbon footprint. Participants shopped from their home in an online store containing 612 existing food products and 39 existing non-food products for which we had data on carbon footprint, over three successive weeks, with the interventions occurring in the second and third weeks. Choice architecture reduced carbon footprint significantly in the third week by reducing the proportion of choices made in the high-carbon aisle. The carbon tax reduced carbon footprint in both weeks, primarily by reducing overall spend. The goal priming banner led to a small reduction in carbon footprint in the second week only. Thus, the design of the marketplace plays an important role in achieving the policy objective of reducing greenhouse gas emissions.

全球温度的升高要求从消费者的选择中大量减少温室气体的排放。我们使用一个实验性激励兼容的在线超级市场来分析基于碳的选择架构的效果，该架构为高，中和低碳足迹组的客户提供商品，以减少食品篮的碳足迹。我们将这种选择架构与其他两项政策干预措施联系在一起：对所有杂货产品征收红利-碳排放税；和道德目标启动，使用在线横幅广告指出减少一个人的碳足迹在道德上很重要。参与者连续三周在网上商店里购物，其中有612种现有食品和39种现有非食品产品，我们拥有其碳足迹数据，干预在第二周和第三周进行。选择架构减少了在高碳通道中做出选择的比例，从而在第三周内显着减少了碳足迹。碳税主要通过减少总支出来减少两个星期的碳足迹。目标启动标语仅在第二周就减少了碳足迹。因此，市场的设计在实现减少温室气体排放的政策目标中起着重要作用。