ESPACE-DEV, Univ Montpellier, IRD, Univ Guyane, Univ Reunion, Univ Antilles, Univ Avignon, Maison de la Télédétection, 500 rue Jean-François Breton, F-34093, Montpellier, Cedex, France.
Institute for Agro-Environmental Sciences, National Agriculture and Food Research Organization, 3-1-3 Kannondai, Tsukuba, Ibaraki, 305-8604, Japan.
Sci Rep. 2019 Sep 6;9(1):12834. doi: 10.1038/s41598-019-49167-0.
Achieving food security goals in West Africa will depend on the capacity of the agricultural sector to feed the rapidly growing population and to moderate the adverse impacts of climate change. Indeed, a number of studies anticipate a reduction of the crop yield of the main staple food crops in the region in the coming decades due to global warming. Here, we found that crop production might have already been affected by climate change, with significant yield losses estimated in the historical past. We used a large ensemble of historical climate simulations derived from an atmospheric general circulation model and two process-based crop models, SARRA-H and CYGMA, to evaluate the effects of historical climate change on crop production in West Africa. We generated two ensembles of 100 historical simulations of yields of sorghum and millet corresponding to two climate conditions for each crop model. One ensemble is based on a realistic simulation of the actual climate, while the other is based on a climate simulation that does not account for human influences on climate systems (that is, the non-warming counterfactual climate condition). We found that the last simulated decade, 2000-2009, is approximately 1 °C warmer in West Africa in the ensemble accounting for human influences on climate, with more frequent heat and rainfall extremes. These altered climate conditions have led to regional average yield reductions of 10-20% for millet and 5-15% for sorghum in the two crop models. We found that the average annual production losses across West Africa in 2000-2009 associated with historical climate change, relative to a non-warming counterfactual condition (that is, pre-industrial climate), accounted for 2.33-4.02 billion USD for millet and 0.73-2.17 billion USD for sorghum. The estimates of production losses presented here can be a basis for the loss and damage associated with climate change to date and useful in estimating the costs of the adaptation of crop production systems in the region.
实现西非的粮食安全目标将取决于农业部门的能力，既要养活不断增长的人口，又要减轻气候变化的不利影响。事实上，一些研究预计，由于全球变暖，该地区主要主食作物的作物产量在未来几十年将会下降。在这里，我们发现气候变化已经对作物生产产生了影响，过去的历史数据显示作物产量已经出现了显著损失。我们利用大气环流模型和两个基于过程的作物模型（SARRA-H 和 CYGMA）产生的大量历史气候模拟集合来评估历史气候变化对西非作物生产的影响。我们为每个作物模型生成了两组合集，每组 100 个历史模拟的高粱和小米产量。一个集合基于对实际气候的现实模拟，而另一个集合基于不考虑人类对气候系统影响的气候模拟（即非变暖的反事实气候条件）。我们发现，在考虑人类对气候影响的集合中，过去模拟的十年（2000-2009 年）西非的温度大约升高了 1°C，且更频繁地出现极端高温和降雨。这些变化的气候条件导致两个作物模型中小米和高粱的区域平均产量分别减少了 10-20%和 5-15%。我们发现，相对于非变暖的反事实条件（即前工业化气候），2000-2009 年历史气候变化导致整个西非的年均产量损失分别为小米 23.33-40.20 亿美元和高粱 0.73-2.17 亿美元。这里提出的产量损失估计可以作为迄今为止与气候变化相关的损失和损害的基础，并有助于估计该地区作物生产系统适应气候变化的成本。
