Khanh Do Ngoc, Varquez Alvin C G, Kanda Manabu
Department of Transdisciplinary Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo, 152-8550, Japan.
Heliyon. 2023 Apr 18;9(4):e15511. doi: 10.1016/j.heliyon.2023.e15511. eCollection 2023 Apr.
Cities warm up due to two main factors: global climate change and urbanization-induced warming (so-called, urban heat island effect). In the projection of future climate, coarse-resolution global climate models are not suitable for looking into the heterogeneous urban surface and their changes. On the other hand, regional climate models, which are capable of looking into cities in detail, have never been used to investigate the global urban climate. Here we show that urbanization significantly increases exposure to extreme warming for megacity residents. We reflect urbanization between the 2010s and the 2050s into our model by considering the spatiotemporal change in urban surface (buildings and anthropogenic heat emissions) induced by urban population and economic growth. We found that in the 2050s, under the worst-case scenario, 78 percent of megacity residents will be exposed to 2.5 °Cwarming, much higher than the projection of 65 percent when urban warming is left out. Our results highlight the importance of accounting for local urbanization in future global urban climate projection.
全球气候变化和城市化引发的升温（即所谓的城市热岛效应）。在未来气候预测中，低分辨率的全球气候模型并不适合研究城市表面的异质性及其变化。另一方面，能够详细研究城市的区域气候模型从未被用于调查全球城市气候。在此我们表明，城市化显著增加了特大城市居民面临极端升温的风险。我们通过考虑城市人口和经济增长引起的城市表面（建筑物和人为热排放）的时空变化，将20世纪10年代至2050年代的城市化情况纳入我们的模型。我们发现，在2050年代，在最坏的情况下，78%的特大城市居民将面临2.5摄氏度的升温，远高于不考虑城市升温时预测的65%。我们的结果凸显了在未来全球城市气候预测中考虑当地城市化的重要性。
