Since AR5, numerous drastic short-term responses have been observed in lakes and rivers, to both expected seasonal extreme events and unexpected supra-seasonal extremes extending over multiple seasons. Consequences for ecosystem functioning are not well understood . Increasing frequencies of severe floods and droughts attributed to climate change are major threats for river ecosystems . While extreme floods cause massive physical disturbance, moderate floods can have positive effects, providing woody debris that contributes to habitat complexity and diversity, flushing fine sediments, dissolving organic carbon and providing important food sources from terrestrial origins . Droughts reduce river habitat diversity and connectivity, threatening aquatic species, especially in deserts and arid regions .
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report