Green roofs are known to be an effective roofing strategy that mitigate urban heat island effects, increase carbon uptake, and reduce energy consumption through thermal insulation. The degree of benefits from green roofs is known to vary largely by regional climatic conditions. With rapidly rising global temperature and elevated CO concentrations, the effectiveness of green roofs under the future climate remains unclear. Here we use MLCan, a multi-layer canopy model, to simulate a green roof and a traditional roof under projected climate scenarios and evaluate the advantage of a green roof. We find that effective thermal insulation makes a green roof the most environmental and economical roofing option in the future. A green roof reduced a building temperature by 4.3 °C and 5.0 °C in a peak month (July) under projected climates in the near (2041–2060) and far (2081–2100) future, respectively. Compared to a traditional roof, thermal buffering from a green roof annually saves 17.4 kW/m and 21.2 kW/m of heating and cooling energy, equivalent to saving $94/m and $114/m in the near and the far future, respectively. In fact, carbon credits produced under different CO levels are not significantly distinctive across four projected climates. A green roof reduces 25% of the net cost (i.e. the sum of installation and maintenance cost, heating and cooling energy cost, and carbon credit; $530/m) under the most altered climate, compared to the current climate. We highlight the amount of energy saved from thermal insulation makes green roofs the most affordable and environmental option to mitigate the climate change effect and resolve urban heat island issues in the coming decades.

中文翻译：

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未来气候下湿润亚热带地区绿色屋顶的环境和经济效益增强

众所周知，绿色屋顶是一种有效的屋顶策略，可以减轻城市热岛效应，增加碳吸收，并通过隔热减少能源消耗。众所周知，绿色屋顶的效益程度很大程度上取决于地区气候条件。随着全球气温迅速上升和二氧化碳浓度升高，绿色屋顶在未来气候下的有效性仍不清楚。在这里，我们使用多层树冠模型 MLCan 来模拟预计气候情景下的绿色屋顶和传统屋顶，并评估绿色屋顶的优势。我们发现，有效的隔热使绿色屋顶成为未来最环保、最经济的屋顶选择。根据预测的近期（2041-2060年）和远期（2081-2100年）气候，绿色屋顶在高峰月（7月）将建筑温度分别降低了4.3°C和5.0°C。与传统屋顶相比，绿色屋顶的热缓冲每年可节省 17.4 kW/m 和 21.2 kW/m 的供暖和制冷能源，相当于在近期和远期分别节省 94 美元/m 和 114 美元/m 。事实上，在四种预测气候中，不同二氧化碳水平下产生的碳信用额并没有显着差异。与当前气候相比，在变化最严重的气候条件下，绿色屋顶可减少 25% 的净成本（即安装和维护成本、供暖和制冷能源成本以及碳信用额的总和；530 美元/平方米）。我们强调，隔热节省的能源使绿色屋顶成为未来几十年减轻气候变化影响和解决城市热岛问题的最经济实惠的环保选择。