I recently wrote an article about this ('COVID and Climate: A Tale of Two Crises'), and I was surprised to find how many reports had already been published on the matter. I remember seeing a post from an Italian newspaper showing how almost every canal in Venice had cleared up, and jellyfish and a pretty big octopus were encountered there too. This showed the effects of lockdowns on marine life, and how impactful ships and other human activities there can be. In my article, I wrote about air and water quality improving in India and China, amongst other places, where air pollution decreased and water bodies like the Ganga river cleared up.
However, then I think about the amount of masks that were thrown away and ended up in oceans, and how much online shopping has increased in the meantime... I guess the glimmer of hope only lasted for a little while, but I really hope leaders around the world have noticed this brief change so that they can stop and think for a second...