The COVID-19 pandemic inadvertently offered a condition to evaluate how abrupt human-activity reductions affect freshwater ecosystems, particularly water turbidity. Using satellite-derived data from 774 lakes worldwide (2017–2022), here we show turbidity declined significantly in highly turbid zones of lakes following COVID-19 containment, with minor effects elsewhere. Globally, average peak turbidity decreased 7.0% in 2020 relative to 2019; 5.9% was directly attributable to containment measures, independent of climate. Without these measures, peak turbidity would have been ~5% higher (0.45 Nephelometric Turbidity Units) during 2020–2022. Lakes in regions with stricter containment and higher anthropogenic footprint exhibited larger declines and faster rebounds post-restriction. Among individual lakes, 75.2% experienced average peak turbidity reductions. For 168 lakes, containment-driven improvements averaged –18.6%, strongly correlated with reduced night-time light as a proxy for anthropogenic inputs. By disentangling human and climatic influences, our study provides globally relevant, actionable insights for targeted lake restoration strategies. COVID-19 containment and control caused a clear, short-term drop in lake peak turbidity and improved nearshore water quality, especially in human-impacted regions, according to analyses of satellite data from 774 lakes worldwide.
Wu et al. (Thu,) studied this question.