Urban cooling inequality

Climate warming disproportionately impacts countries in the Global South by increasing extreme heat exposure. However, geographic disparities in adaptation capacity are unclear. Here, we assess global inequality in green infrastructure, which urban residents critically rely on to mitigate outdoor heat stress. We use remote sensing data to quantify daytime cooling by urban greenery in the warm seasons across the ~500 largest cities globally. We show a striking contrast, with Global South cities having ~70% of the cooling capacity of cities in the Global North (2.5±1.0°C vs. 3.6±1.7°C). A similar gap occurs for the cooling adaptation benefits received by an average resident in these cities (2.2±0.9°C vs. 3.4±1.7°C). This cooling adaptation inequality is due to discrepancies in green space quantity and quality between cities in the Global North and South, shaped by socioeconomic and natural factors. Our analyses further suggest a vast potential for enhancing cooling adaptation while reducing global inequality.

气候变暖通过加剧极端热暴露，对全球南方（Global South）各国造成不成比例的影响。然而，不同地区间适应能力的地理差异尚未明确。本研究评估了全球绿色基础设施（green infrastructure）方面的不平等状况——城市居民可依托该设施有效缓解户外热应激。我们借助遥感数据，对全球约500个大型城市暖季期间城市植被的日间降温效应进行量化分析。研究结果呈现出显著差异：全球南方城市的降温能力仅约为全球北方（Global North）城市的70%（分别为2.5±1.0℃与3.6±1.7℃）。这些城市的普通居民所能获得的降温适配收益也存在类似差距（分别为2.2±0.9℃与3.4±1.7℃）。这种降温适配不平等现象，源于全球南北城市在绿地数量与质量上的差异，而该差异受社会经济与自然因素共同塑造。我们的分析进一步表明，在提升降温适配能力的同时缩小全球不平等，存在巨大潜力。