I think a lot about the decline of wilderness and just want to mention that animal agriculture drives a huge amount of the land pressure driving conversion of intact ecosystems into degraded states. 3/4 of the world's ag land is devoted to grazing or growing livestock feed. If the world went vegan then biodiversity and ecosystem loss would probably reverse. I think even the marginal impact an individual choice is significant. https://ourworldindata.org/land-use-diets

See also: https://www.nature.com/articles/536143a https://www.science.org/doi/epdf/10.1126/sciadv.abm9982