Why is over-population never at the forefront of the climate agenda?

Why do all the self proclaimed tree huggers not kill themselves if that will save the planet?

Because as ALWAYS they are cowards and liars that really don't care about the planet

It is, global birth rates are falling dramatically because of more women in education and work, as well as greater access to contraception leading to women choosing to have fewer children, however in my opinion, it's not enough

You are right that climate change is density-dependent to a great extent. It was abruptly demonstrated by the effect of the Covid-19 pandemic on pollutants. OTOH, what are you going to do about it? Populations tend to go through four demographic stages. The first is high birth and death rates. Populations don't become relatively stable until the fourth phase, with a high rate of development, population around the carrying capacity, and lots of pollution per individual. While starting WWIII might affect populations, I suspect that those days are over. It is more efficient to start small proxy wars and attack via the internet. Why does Russia care about the US elections? Because having a doofus in charge leads to relaxation of environmental standards, in turn leading to global warming, which leads to open water in the Arctic, which is good for Russian shipping and brings in money from other countries shipping via the polar route. There is no way that Russia would allow international action to slow global warming. They actually benefit while the rest of the world suffers. Seen any hurricanes in Russia lately?