Impact of climate change on crop suitability in sub-Saharan Africa in parameterized and convection-permitting regional climate models
Impact of climate change on crop suitability in sub-Saharan Africa in parameterized and convection-permitting regional climate models
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DOI：
10.1088/1748-9326/ab9daf
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发表时间：
2020-09-01
影响因子：
6.7
通讯作者：
Marsham, John
中科院分区：
文献类型：
--
作者：
Chapman, Sarah;Birch, Cathryn;Marsham, John
由于目前气温高，而且依赖农业，撒哈拉以南非洲极易受到气候变化的影响。我们使用一套全面的全球（CMIP 5）和区域（CORDEX-非洲）气候预测和一个新的对流允许泛非洲模拟（及其参数化的对应），以检查降雨和温度的变化和对玉米，木薯和大豆的作物适宜性的影响，在撒哈拉以南非洲到2100年（RCP 8.5）。这是第一次使用显式对流模拟来研究非洲的作物适宜性。气温上升和降雨量减少导致撒哈拉以南非洲大部分地区不适合多种主食作物，这可能需要过渡到更耐热和耐旱的作物，以确保粮食和营养安全。大豆对温度升高有抵抗力，但玉米和木薯则不然，导致作物适宜性下降。包括极端温度的敏感性导致更大的下降，玉米的适合性比当这被排除在外。详细探讨了坦桑尼亚、马拉维、赞比亚和南非的结果。在每个国家，预测范围包括湿润和干燥，但大多数模型预测降雨量下降导致作物适宜性下降，坦桑尼亚除外。显式对流与更多的高温极端，但平均温度和总降雨量，并由此产生的适宜性分析几乎没有系统的影响。全球模式的不确定性，而不是对流参数化，仍然构成了未来气候的不确定性的最大部分。如果适宜性包括一个更全面的极端处理，显式对流可能有更大的影响。这项工作突出了全球气候预测对作物适宜性预测的主要不确定性，以及需要改进关于非洲作物对极端情况敏感性的信息，以便更好地预测和更好地利用新一代的显式对流模型。
Due to high present-day temperatures and reliance on rainfed agriculture, sub-Saharan Africa is highly vulnerable to climate change. We use a comprehensive set of global (CMIP5) and regional (CORDEX-Africa) climate projections and a new convection-permitting pan-Africa simulation (and its parameterized counterpart) to examine changes in rainfall and temperature and the impact on crop suitability of maize, cassava and soybean in sub-Saharan Africa by 2100 (RCP8.5). This is the first time an explicit-convection simulation has been used to examine crop suitability in Africa. Increasing temperatures and declining rainfall led to large parts of sub-Saharan Africa becoming unsuitable for multiple staple crops, which may necessitate a transition to more heat and drought resistant crops to ensure food and nutrition security. Soybean was resilient to temperature increases, however maize and cassava were not, leading to declines in crop suitability. Inclusion of sensitivity to extreme temperatures led to larger declines in maize suitability than when this was excluded. The results were explored in detail for Tanzania, Malawi, Zambia and South Africa. In each country the range of projections included wetting and drying, but the majority of models projected rainfall declines leading to declines in crop suitability, except in Tanzania. Explicit-convection was associated with more high temperature extremes, but had little systematic impact on average temperature and total rainfall, and the resulting suitability analysis. Global model uncertainty, rather than convection parameterizations, still makes up the largest part of the uncertainty in future climate. Explicit-convection may have more impact if suitability included a more comprehensive treatment of extremes. This work highlights the key uncertainty from global climate projections for crop suitability projections, and the need for improved information on sensitivities of African crops to extremes, in order to give better predictions and make better use of the new generation of explicit-convection models.