Agricultural production is strongly affected by and a major contributor to climate change. Agriculture and land-use change account for a quarter of total global emissions of greenhouse gases (GHG). Agriculture receives around US$600 billion per year worldwide in government support. No rigorous quantification of the impact of this support on GHG emissions has been available. This article helps fill the void. Here, we find that, while over the years the government support has incentivized the development of high-emission farming systems, at present, the support only has a small impact in terms of inducing additional global GHG emissions from agricultural production; partly because support is not systematically biased towards high-emission products, and partly because support generated by trade protection reduces demand for some high-emission products by raising their consumer prices. Substantially reducing GHG emissions from agriculture while safeguarding food security requires a more comprehensive revamping of existing support to agriculture and food consumption.

农业生产受到气候变化的强烈影响，并成为气候变化的主要贡献者。农业和土地利用变化占全球温室气体排放总量的四分之一。世界范围内，农业每年在政府支持下获得约6000亿美元。目前尚无法对这种支持对温室气体排放的影响进行严格的量化。本文有助于填补空白。在这里，我们发现，尽管多年来政府的支持激励了高排放农业体系的发展，但目前，该支持仅在从农业生产中引起全球温室气体额外排放方面产生了很小的影响；部分原因是支持并未系统地偏向高排放产品，部分原因是贸易保护产生的支持通过提高消费者价格降低了对某些高排放产品的需求。在保障粮食安全的同时，要大幅减少农业产生的温室气体排放，就需要对农业和粮食消费的现有支持进行更全面的调整。