Anthropogenic climate change has influenced global river flow seasonality

Abstract

Riverine ecosystems have adapted to natural discharge variations across seasons. However, evidence suggesting that climate change has already impacted magnitudes of river flow seasonality is limited to local studies, mainly focusing on changes of mean or extreme flows. This study introduces the use of apportionment entropy as a robust measure to assess flow-volume nonuniformity across seasons, enabling a global analysis. We found that ~21% of long-term river gauging stations exhibit significant alterations in seasonal flow distributions, but two-thirds of these are unrelated to trends in annual mean discharge. By combining a data-driven runoff reconstruction with state-of-the-art hydrological simulations, we identified a discernible weakening of river flow seasonality in northern high latitudes (above 50°N), a phenomenon directly linked to anthropogenic climate forcing.

Quantitative Contributions of Climate and Human Activities to Streamflow and Sediment Load in the Xiliugou Basin of China

“…Studies indicate that the "sediment interception and water exchange" project not only intercepted 3.21 × 10 6 tons of sediment load from the Ten Kongduis but also replaced downstream river sediment load with 2.57 × 10 7 m 3 of streamflow [30,46]. While these human activities may indirectly influence climate change [47,48], it is undeniable that human activities have played a crucial role in the variation in sediment load in the Xiliugou Basin, aligning with the findings of this study. Currently, human activities have greatly improved the streamflow-sediment load relationship in the Xiliugou Basin, enhancing the quality of the ecological environment.…”