COVID-19's environmental impacts: Challenges and implications for the future

Strict measures have curbed the spread of COVID-19, but waste generation and movement limitations have had an unintended impact on the environment over the past 3 years (2020-2022). Many studies have summarized the observed and potential environmental impacts associated with COVID-19, however, only a few have quantified and compared the effects of these unintended environmental impacts; moreover, whether COVID-19 policy stringency had the same effects on the main environmental topic (i.e., CO₂ emissions) across the 3 years remains unclear. To answer these questions, we conducted a systematic review of the recent literature and analyzed the main findings. We found that the positive environmental effects of COVID-19 have received more attention than the negative ones (50.6 % versus 35.7 %), especially in emissions reduction (34 % of total literature). Medical waste (14.5 %) received the highest attention among the negative impacts. Although global emission reduction, especially in terms of CO₂, has received significant attention, the positive impacts were temporary and only detected in 2020. Strict COVID-19 policies had a more profound and significant effect on CO₂ emissions in the aviation sector than in the power and industry sectors. For example, compared with 2019, international aviation related CO₂ emissions dropped by 59 %, 49 %, and 25 % in 2020, 2021, and 2022, respectively, while industry related ones dropped by only 3.16 % in 2020. According to our developed evaluation matrix, medical wastes and their associated effects, including the persistent pollution caused by antibiotic resistance genes, heavy metals and microplastics, are the main challenges post the pandemic, especially in China and India, which may counteract the temporary environmental benefits of COVID-19. Overall, the presented results demonstrate methods to quantify the environmental effects of COVID-19 and provide directions for policymakers to develop measures to address the associated environmental issues in the post-COVID-19 world.