Population

All environmental issues are ultimately population issues. Even the most wasteful and polluting industrial processes would have minimal environmental impact if the population were small enough.

While this might lead some to say "Thanos was right", this is fortunately a problem can easily solve itself without resorting to genocide or authoritarian limits on births.

All evidence shows that education, especially women's education, low infant mortality, and access to birth control naturally result in a declining population.

We just need to avoid creating economic systems that rely on an increasing population to fund things like retirement pensions and growth for growth sake economics.