Siabi Ebenezer Kwadwo, Awafo Edward Abingya, Kabobah Amos Tiereyangn, Derkyi Nana Sarfo Agyeman, Akpoti Komlavi, Anornu Geophrey Kwame, Yazdanie Mashael
Earth Observation Research and Innovation Center (EORIC), University of Energy and Natural Resources, P.O. Box 214, Sunyani, Ghana.
Regional Center for Energy and Environmental Sustainability, University of Energy and Natural Resources, P.O. Box 214, Sunyani, Ghana.
Discov Sustain. 2024;5(1):167. doi: 10.1007/s43621-024-00352-w. Epub 2024 Jul 29.
Climate change leading to Climate extremes in the twenty-first century is more evident in megacities across the world, especially in West Africa. The Greater Accra region is one of the most populated regions in West Africa. As a result, the region has become more susceptible to climate extremes such as floods, heatwaves, and droughts. The study employed the Coupled Model Intercomparison Project 6 models in simulating climate extreme indices under the Shared Socioeconomic Pathway scenarios (SSPs) over West Africa between 1979 and 2059 as exemplified by the Greater Accra region. The study observed a generally weak drought in the historical period and expected to intensify especially under SSP585 in Greater Accra. For instance, continuous dry days (CDD) reveal an increasing trend under the SSPs. Similarly, the overall projected trend of CDD over West Africa reveals an increase signifying a more frequent and longer drought in the future. The flood indices revealed a surge in the intensity and duration of extreme precipitation events under the SSPs in the region. For instance, R99pTOT and Rx5days are expected to significantly increase under the SSPs with intensification under the SSP245, SSP370, and SSP585. A similar trend has been projected across West Africa, especially along the Guinean coast. The study foresees a gradual and intensifying rise in heatwave indices over the Greater Accra region. The warming and cooling indices reveal an increasing and decreasing trend respectively in the historical period as well as under the SSPs particularly within urban centers like Accra and Tema. Most West African countries are projected to observe more frequent warm days and nights with cold nights and days becoming less frequent. Expected effects of future climate extreme indices pose potential threats to the water, food, and energy systems as well as trigger recurrent floods and droughts over Greater Accra. The findings of the study are expected to inform climate policies and the nationally determined contribution of the Paris Agreement as well as address the sustainable development goal 11 (Sustainable cities) and 13 (Climate action) in West Africa.
气候变化导致21世纪气候极端事件在世界各地的特大城市中更为明显，尤其是在西非。大阿克拉地区是西非人口最密集的地区之一。因此，该地区更容易受到洪水、热浪和干旱等极端气候的影响。该研究采用耦合模式比较计划第6阶段的模型，以大阿克拉地区为例，模拟1979年至2059年期间西非共享社会经济路径情景（SSP）下的气候极端指数。该研究观察到历史时期干旱普遍较弱，并预计在大阿克拉地区尤其是在SSP585情景下干旱会加剧。例如，连续干旱日数（CDD）在SSP情景下呈上升趋势。同样，整个西非地区CDD的总体预测趋势显示增加，这意味着未来干旱将更频繁且持续时间更长。洪水指数显示该地区在SSP情景下极端降水事件的强度和持续时间激增。例如，预计R99pTOT和Rx5days在SSP情景下会显著增加，在SSP245、SSP370和SSP585情景下会加剧。整个西非地区，尤其是几内亚海岸沿线，预计也会出现类似趋势。该研究预测大阿克拉地区热浪指数将逐渐加剧。变暖指数和变冷指数在历史时期以及SSP情景下，特别是在阿克拉和特马等城市中心，分别呈现上升和下降趋势。预计大多数西非国家将观测到更频繁的温暖白天和夜晚，寒冷的夜晚和白天则变得不那么频繁。未来气候极端指数的预期影响对水、食物和能源系统构成潜在威胁，并引发大阿克拉地区反复出现的洪水和干旱。该研究结果有望为气候政策和《巴黎协定》的国家自主贡献提供参考，并有助于实现西非的可持续发展目标11（可持续城市）和13（气候行动）。
