Eyni Ali, Zaitchik Benjamin F, Hobbs Benjamin F, Hadjimichael Antonia, Shi Rui
Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, MD, USA.
Department of Environmental Health and Engineering, Johns Hopkins University, Baltimore, MD, USA.
Sci Rep. 2025 Mar 20;15(1):9594. doi: 10.1038/s41598-025-93896-4.
Global warming and the rise in extreme heat days elevate the risk of heat-related mortalities, particularly in cities due to the Urban Heat Island (UHI) effect and vulnerabilities tied to housing, exposure, and health conditions. City planners can mitigate these effects through urban adaptive actions. UHI mitigation, however, needs to balance several goals: strategies that maximize temperature reduction or minimize their impacts may not be best for cost effectiveness, carbon emissions, environmental amenities, health impacts, or distributional outcomes. Here, we implement a multi-objective robust decision-making tool for heat mitigation-the City-Heat Equity Adaptation Tool (City-HEAT)-to identify potential heat mitigation pathways at neighborhood scales. We find that more expensive pathways tend to have larger benefits in reducing heat-related deaths, but that these pathways sometimes underperform against other alternatives on reducing inequality in mortality outcomes. Pathways that focus on tree planting, a popular and powerful tool for UHI reduction, were found to be expensive and less effective at reducing health disparities than more diversified pathways, if no specific measures are taken to target tree distribution for distributional benefit. The generated pathways can reduce Baltimore's heat related mortality by 81-670 deaths in the next 50 years, considering different investment plans in the city's neighborhoods. We also find that these results are relatively insensitive to expectations for future warming: pathways designed for high warming rates are similar to those designed for low warming rates, suggesting that general strategies for UHI mitigation can be robust to climate uncertainties.
全球变暖和极端高温天数的增加提升了与高温相关的死亡风险，尤其是在城市中，这是由于城市热岛（UHI）效应以及与住房、暴露情况和健康状况相关的脆弱性所致。城市规划者可以通过城市适应性行动来减轻这些影响。然而，减轻城市热岛效应需要平衡多个目标：使温度降低最大化或使其影响最小化的策略可能在成本效益、碳排放、环境舒适性、健康影响或分配结果方面并非最佳选择。在此，我们实施了一种用于减轻高温影响的多目标稳健决策工具——城市热公平适应工具（City-HEAT），以确定社区尺度上潜在的减轻高温影响途径。我们发现，成本更高的途径在减少与高温相关的死亡方面往往具有更大的效益，但这些途径在降低死亡率结果的不平等性方面有时表现不如其他替代方案。如果不采取具体措施使树木分布具有分配效益，那么专注于植树（一种减轻城市热岛效应常用且有效的工具）的途径被发现成本高昂，且在减少健康差距方面效果不如更多样化的途径。考虑到该市各社区的不同投资计划，所生成的途径在未来50年内可使巴尔的摩与高温相关的死亡人数减少81 - 670人。我们还发现，这些结果对未来变暖的预期相对不敏感：为高变暖率设计的途径与为低变暖率设计的途径相似，这表明减轻城市热岛效应的一般策略对气候不确定性具有稳健性。
