Department of Environment and Geography, University of York, York, United Kingdom.
Institute for Climate and Atmospheric Sciences (ICAS), School of Earth and Environment, University of Leeds, Leeds, United Kingdom.
PLoS One. 2021 Jul 13;16(7):e0254371. doi: 10.1371/journal.pone.0254371. eCollection 2021.
Due to the combined effects of urban growth and climate change, rapid urbanisation is particularly challenging in African cities. Areas that will house a large proportion of the urban population in the future coincide with where natural hazards are expected to occur, and where hazard risk management institutions, knowledge, and capacity are often lacking. One of the challenges posed by rapid urbanisation is the Urban Heat Island (UHI) effect, whereby urban areas are warmer than the surrounding rural areas. This study investigates urbanisation patterns and alterations in surface UHI (SUHI) intensity for the Kampala urban cluster, Uganda. Analyses show that between 1995 and 2017, Kampala underwent extensive changes to its urban built-up area. From the centre of the city to adjoining non-built up areas in all directions, the urban land cover increased from 12,133 ha in 1995 to 25,389 ha in 2016. The area of SUHI intensity in Kampala expanded significantly over the 15-year period of study, expanding from 22,910 ha in 2003 to 27,900 ha in 2016, while the annual daytime SUHI of 2.2°C in 2003 had decreased to 1.9°C by 2017. Although SUHI intensity decreased in some parts of the city, elsewhere it increased, suggesting that urbanisation does not always lead to a deterioration of environmental conditions. We postulate that urban development may therefore not necessarily create an undesirable impact on local climate if it is properly managed. Rapidly growing cities in Africa and elsewhere should ensure that the dynamics of their development are directed towards mitigating potentially harmful environmental impacts, such as UHI effect through careful planning that considers both bluespaces and greenspaces.
由于城市发展和气候变化的综合影响，快速城市化在非洲城市中尤其具有挑战性。未来将容纳大量城市人口的地区与预计发生自然灾害的地区重合，而这些地区的灾害风险管理机构、知识和能力往往匮乏。快速城市化带来的挑战之一是城市热岛（UHI）效应，即城市地区比周围农村地区更热。本研究调查了乌干达坎帕拉城市群的城市化模式和表面 UHI（SUHI）强度的变化。分析表明，在 1995 年至 2017 年间，坎帕拉的城市建成区发生了广泛变化。从市中心到各个方向的毗邻非建成区，城市土地覆盖面积从 1995 年的 12133 公顷增加到 2016 年的 25389 公顷。在 15 年的研究期间，坎帕拉的 SUHI 强度区域显著扩大，从 2003 年的 22910 公顷扩大到 2016 年的 27900 公顷，而 2003 年白天的 SUHI 从 2.2°C 下降到 2017 年的 1.9°C。尽管城市部分地区的 SUHI 强度有所下降，但其他地区有所上升，这表明城市化并不总是导致环境条件恶化。因此，如果城市发展得到妥善管理，我们假设它不一定会对当地气候产生不良影响。非洲和其他地区快速增长的城市应确保其发展动态旨在减轻 UHI 效应等潜在有害环境影响，方法是通过考虑蓝色空间和绿色空间的精心规划来引导发展。
