The study I linked on The Limits of Growth did not predict 15 years. They predicted between 2030 and 2040. The original authors of that study have reasserted just last year that they still believe it to be true. IPCC and the nature study I linked have predicted collapse in the same time frame. So I am not sure the doomers that you are referencing were credible. However, I place my trust in science. The fact that scientists are literally screaming that we are headed towards extinction in the time frame I mentioned, the fact that we have lost 70% of species since 1970, and other data backing up the claims is enough for me to be convinced. I am not sure what it would take for you to be convinced.

> I've been hearing for most of my life, at least the last 40 or so years

Well, maybe you don't care that 2/3 of animal populations have disappeared in the last few decades, but I guess for many it counts as a big problem.

Anyway don't be sad, we are starting to actually feel the consequences of climate change, so stay tuned: famines and global instability might still come in your lifetime, or at least in your children lifetime!

(I assume you are at least 50 if you've been aware of this for 40 years)