Department of Water Science and Engineering, IHE Delft Institute for Water Education P.O. Box 3015 2610, DA, Delft, The Netherlands.
Harbour, Coastal and Offshore Engineering, Deltares, PO Box 177, 2600 MH, Delft, The Netherlands.
Sci Rep. 2019 Jun 25;9(1):9236. doi: 10.1038/s41598-019-45442-2.
The world's large rivers are under stress and experiencing unprecedented changes in hydrology, ecosystems, and fluvial sediment loads. Many of these rivers terminate at the great deltas of the world (home to 500 million people), which depend on fluvial sediments for their very existence. While fluvial sediment loads of large rivers have already been greatly modified by human activities, climate change is expected to further exacerbate the situation. But how does the effect of climate change on fluvial sediment loads compare with that of human impacts? Here, we address this question by combining historical observations and 21 century projections for one of the world's largest 25 rivers containing two mega dams; Pearl River, China. Our analysis shows that variations in fluvial sediment supply to the coast from the Pearl river over a ~150 year study period are dominated by human activities. Projected climate change driven 21 century increases in riverflow will only compensate for about 1% of the human induced deficit in sediment load, leading to the coastal zone being starved of about 6000 Mt of sediment over the remainder of this century. A similar dominance of human impacts on fluvial sediment supply is likely at other heavily engineered rivers.
世界上的大河正承受着压力，其水文、生态系统和河流泥沙负荷都经历着前所未有的变化。这些河流中的许多都在世界上的大三角洲处入海（三角洲居住着 5 亿人口），而这些三角洲的存在依赖于河流泥沙。尽管人类活动已经极大地改变了大河的河流泥沙负荷，但气候变化预计将进一步加剧这一状况。然而，气候变化对河流泥沙负荷的影响与人类活动的影响相比如何呢？在这里，我们通过结合历史观测和对世界上最大的 25 条河流之一（其中包含两座大型水坝）——中国珠江的 21 世纪预测，来回答这个问题。我们的分析表明，在长达约 150 年的研究期间，珠江向海岸输送的河流泥沙供应的变化主要是由人类活动引起的。预计气候变化导致的 21 世纪河流径流量增加，仅能弥补人类活动引起的泥沙负荷减少的约 1%，这将导致在本世纪剩余时间里，该海岸带将缺少约 6 亿吨的泥沙。在其他受人类活动严重影响的河流中，人类活动对河流泥沙供应的影响可能也占据主导地位。
