It's no joke
There's no argument about the demographics of developed countries regarding lowered birth rates and higher mortality, significant population increases in these countries are largely due to immigration. Immigrants within the first world countries are largely responsible for population increases within these countries. The main issue is that developing countries are in the majority on planet Earth and are significantly adding to the global population. We've already seen huge population increases during the 19th amd 20th centuries (current developed world) and conservative estimates suggest that the rate of increase will continue for at least another half century. The rate of increase is the cause for concern given the established relationship with current human activity and greenhouse gases.
Global warming is fact, it's not conjecture. Global warming is increasing. Greenhouse gases are increasingly being released into the atmosphere, the rate of increase can now be seen to be coming from the third world although the first world countries are by far the highest contributors. Developing countries aspire to the lifestyles of the developed world, this is happening in a hugely effective way by virtue of the free market commercial engines of the developed world.
As is currently recorded as the worst case, the US on average per person consumption of global hectares of biocapacity is almost 10 global hectares as contrasted to just over 5 for a Western Europeans and just only one half (0.5) for an Indian. This relationship suggests just how the potential increase in greenhouse emissions could be. I'm afraid it also points to us (as a developed country citizen) as to how we need to take ownership amd control for the measures that are required to start to resolve the problem. Herein is real problem. I hope we (the first world) will step up to the mark in time. I don't think this will happen but hope I am wrong.
Established science. Tree hugging is good, CO2 consumers whilst they live, greenhouse gas providers when they die. The good logic is that we are doing this to ourselves.