Impacts of COVID-19 Lockdowns on Environmental Degradation and Climate Change: A Review

The COVID-19 pandemic, first identified in late 2019, rapidly transformed social and economic systems worldwide. To contain its spread, many governments imposed strict restrictions that closed businesses, schools, airports, factories, and other socio-economic activities. These unprecedented measures created a global “experiment” in reducing human pressures on the environment, providing valuable insights into how ecosystems respond when anthropogenic activities are curtailed. Short-term environmental improvements were widely reported. Urban air quality improved markedly, with nitrogen dioxide concentrations falling and global daily CO<sub>2</sub> emissions declining by up to 17% at the peak of lockdowns. Air pollution dropped by about 25% in China and nearly 50% in New York compared with the previous year. Water bodies also exhibited temporary gains, including greater clarity and reductions in biochemical and chemical oxygen demand, largely due to reduced industrial discharges. Lockdowns further suppressed anthropogenic noise and seismic activity, while wildlife displayed shifts in movement and behavior during the “anthropause.” At the same time, the pandemic introduced new environmental pressures. Increased household wastewater and detergent use added pollutant loads to urban systems, while surges in personal protective equipment (PPE) and medical waste intensified plastic pollution risks. Conservation programs were interrupted, and global CO<sub>2</sub> emissions rebounded strongly by 2021, highlighting the temporary nature of early gains. These contrasting outcomes underscore the complexity of human–environment interactions under crisis conditions. While the pandemic revealed the scale of improvement achievable through short-term behavioral change, it also confirmed that durable benefits require systemic policy interventions. Strengthening environmental monitoring, building resilient waste management systems, and aligning recovery strategies with climate and biodiversity objectives are essential to embedding the lessons of the pandemic into long-term sustainability planning. This review therefore synthesizes emerging evidence on the environmental impacts of COVID-19 lockdowns, identifying both opportunities and challenges to inform future climate and sustainability strategies.