Scown Murray W, Dunn Frances E, Dekker Stefan C, van Vuuren Detlef P, Karabil Sitar, Sutanudjaja Edwin H, Santos Maria J, Minderhoud Philip S J, Garmestani Ahjond S, Middelkoop Hans
Lund University Centre for Sustainability Studies (LUCSUS), Lund, Sweden.
Copernicus Institute of Sustainable Development, Utrecht University, Utrecht, Netherlands.
Glob Environ Change. 2023 Sep;82:1-14. doi: 10.1016/j.gloenvcha.2023.102736.
Deltas play a critical role in the ambition to achieve global sustainable development given their relatively large shares in population and productive croplands, as well as their precarious low-lying position between upstream river basin development and rising seas. The large pressures on these systems risk undermining the persistence of delta societies, economies, and ecosystems. We analyse possible future development in 49 deltas around the globe under the Shared Socio-economic and Representative Concentration Pathways until 2100. Population density, urban fraction, and total and irrigated cropland fraction are three to twelve times greater in these deltas, on average, than in the rest of the world. Maximum river water discharges are projected to increase by 11-33 % and river sediment discharges are projected to decrease 26-37 % on average, depending on the scenario. Regional sea-level rise reaches almost 1.0 m by 2100 for certain deltas in the worst-case scenario, increasing to almost 2.0 m of relative rise considering land subsidence. Extreme sea levels could be much higher still-reaching over 4.0 m by 2100 for six of the 49 deltas analysed. Socio-economic conditions to support adaptation are the weakest among deltas with the greatest pressures, compounding the challenge of sustainable development. Asian and African deltas stand out as having heightened socio-economic challenges-huge population and land use pressures in most Asian deltas and the Nile delta; low capacity for adaptation in most African deltas and the Irrawaddy delta. Although, deltas in other parts of the world are not immune from these and other pressures, either. Because of unique pressures and processes operating in deltas, as in other "hotspots" such as small islands, mountains, and semi-arid areas, we recommend greater consideration and conceptualisation of environmental processes in global sustainable development agendas and in the Integrated Assessment Models used to guide global policy.
鉴于三角洲地区在全球人口和高产农田中所占份额相对较大，以及它们在上游流域开发与海平面上升之间所处的危险低洼位置，三角洲在实现全球可持续发展的宏伟目标中发挥着关键作用。这些系统面临的巨大压力有可能破坏三角洲地区社会、经济和生态系统的可持续性。我们分析了到2100年全球49个三角洲地区在共享社会经济路径和代表性浓度路径下可能的未来发展情况。这些三角洲地区的人口密度、城市人口比例以及总耕地和灌溉耕地比例平均比世界其他地区高3至12倍。根据不同情景，预计最大河流水流量将增加11%至33%，河流泥沙流量预计平均减少26%至37%。在最坏的情况下，到2100年某些三角洲地区的区域海平面上升近1.0米，考虑到地面沉降，相对海平面上升将增至近2.0米。极端海平面可能更高——在所分析的49个三角洲中有6个到2100年将超过4.0米。在压力最大的三角洲地区，支持适应的社会经济条件最为薄弱，这加剧了可持续发展的挑战。亚洲和非洲的三角洲地区面临着更为严峻的社会经济挑战——大多数亚洲三角洲和尼罗河三角洲面临着巨大的人口和土地利用压力；大多数非洲三角洲和伊洛瓦底江三角洲的适应能力较低。尽管世界其他地区的三角洲也无法免受这些及其他压力的影响。由于三角洲地区存在独特的压力和过程，如同小岛屿、山区和半干旱地区等其他“热点”地区一样，我们建议在全球可持续发展议程以及用于指导全球政策的综合评估模型中，更多地考虑和概念化环境过程。
