Severe urban heat, a prevalent climate change consequence, endangers city residents globally. Vegetation-based mitigation strategies are commonly employed to address this issue. However, the Middle East and North Africa are under investigated in terms of heat mitigation, despite being one of the regions most vulnerable to climate change. This study assesses the feasibility and climatic implications of wide-scale implementation of green infrastructure (GI) for heat mitigation in Riyadh, Saudi Arabia—a representative desert city characterized by low vegetation coverage, severe summer heat, and drought. Weather research forecasting model (WRF) is used to simulate GI cooling measures in Riyadh’s summer condition, including measures of increasing vegetation coverage up to 60%, considering irrigation and vegetation types (tall/short). In Riyadh, without irrigation, increasing GI fails to cool the city and can even lead to warming (0.1 to 0.3 °C). Despite irrigation, Riyadh’s overall GI cooling effect is 50% lower than GI cooling expectations based on literature meta-analyses, in terms of average peak hour temperature reduction. The study highlights that increased irrigation substantially raises the rate of direct soil evaporation, reducing the proportion of irrigation water used for transpiration and thus diminishing efficiency. Concurrently, water resource management must be tailored to these specific considerations.

严重的城市高温是气候变化的普遍后果，危及全球城市居民。基于植被的缓解策略通常用于解决这个问题。然而，尽管中东和北非是最容易受到气候变化影响的地区之一，但其在缓解热量方面仍在接受调查。本研究评估了沙特阿拉伯利雅得大规模实施绿色基础设施（GI）缓解热量的可行性和气候影响。利雅得是一个典型的沙漠城市，其特点是植被覆盖率低、夏季酷热和干旱。天气研究预报模型 (WRF) 用于模拟利雅得夏季条件下的 GI 降温措施，包括考虑灌溉和植被类型（高/矮），将植被覆盖率提高至 60% 的措施。在利雅得，如果没有灌溉，增加 GI 无法使城市降温，甚至可能导致变暖（0.1 至 0.3 °C）。尽管进行了灌溉，但就平均高峰时段温度降低而言，利雅得的整体胃肠道降温效果比基于文献荟萃分析的胃肠道降温预期低 50%。该研究强调，增加灌溉大大提高了土壤直接蒸发的速度，减少了用于蒸腾的灌溉水的比例，从而降低了效率。同时，水资源管理必须根据这些具体考虑因素进行调整。