Intensifying hydroclimatic changes in North Africa are causing unprecedented floods, droughts, and land degradation patterns that are increasingly associated with human casualties, socioeconomic instabilities, and outflow migrations. These patterns’ and their future forecasts remain largely unquantified, aggravating the impacts on several populous areas. To address this deficiency, we employ pixel-based remote sensing data correlation analysis and soil loss modeling to constrain the uncertainties on the decadal hydroclimatic and ecosystem changes in North Africa. Using cloud-based big data analysis in Google Earth Engine, we establish the convolution between precipitation patterns and surface textural characteristics, evaluating the spatial distribution of soil erosion risks at the continental scale. Our investigation uses a multi-step approach, integrating risk areas derived from soil erosion with high-resolution population data, offering critical insights into zones of different vulnerabilities. Our results unveiled a significant escalation in soil erosion anomalies over the past two decades. In particular, 15 % of the areas receiving precipitation in all of North Africa are currently at medium to high risk of soil erosion versus only 7 % in 2002. These risks are concentrated in urban areas, where each year, ∼29,000 people become highly vulnerable to these hazards, up from ∼22,000 in 2002. These increases are primarily associated with the surge in semi-unformal urban settings and the rise in rain aggressiveness and storminess. These factors, combined with the poor public perception of the imminence of these risks, create hotspots where the impacts are becoming insurmountable, as considered herein for the case of the recent catastrophic floods in Derna, Libya, used as a validation site. We conclude that increased soil erosion will modulate the impacts of upcoming catastrophic floods. As such, a pressing change in urban and land use policies in expansive areas of North Africa is called for to increase their resilience to upcoming hydroclimatic fluctuations.

中文翻译：

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日益严重的土壤侵蚀风险及其在调节北非灾难性洪水中的作用


北非日益加剧的水文气候变化正在造成前所未有的洪水、干旱和土地退化，这些现象与人员伤亡、社会经济不稳定和人口外流日益相关。这些模式及其未来预测在很大程度上仍未量化，加剧了对几个人口稠密地区的影响。为了解决这一缺陷，我们采用基于像素的遥感数据相关分析和土壤流失模型来限制北非十年水文气候和生态系统变化的不确定性。利用谷歌地球引擎中基于云的大数据分析，我们建立了降水模式和地表纹理特征之间的卷积，评估了大陆尺度土壤侵蚀风险的空间分布。我们的调查采用多步骤方法，将土壤侵蚀产生的风险区域与高分辨率人口数据相结合，为不同脆弱区域提供重要见解。我们的研究结果揭示了过去二十年土壤侵蚀异常的显着升级。特别是，目前北非 15% 的降水地区面临中度至高度水土流失风险，而 2002 年这一比例仅为 7%。这些风险集中在城市地区，每年约有 29,000 人变得高度脆弱。这些危害的数量从 2002 年的约 22,000 起有所增加。这些增加主要与半非正规城市环境的激增以及降雨侵袭性和暴风雨的增加有关。 这些因素，再加上公众对这些风险迫在眉睫的认识不足，造成了影响变得难以克服的热点，正如本文所考虑的利比亚德尔纳最近发生的灾难性洪水（用作验证地点）。我们的结论是，土壤侵蚀的加剧将调节即将到来的灾难性洪水的影响。因此，迫切需要改变北非广大地区的城市和土地使用政策，以增强其应对即将到来的水文气候波动的能力。