Who specifically is saying this? I’ve read a lot of predictions and speculation by climate scientists, but never anything remotely like “less than 30 years before we die as a species”.
> People in 1950 predicted the same pessimistic doomsday by the year 2000
I haven’t seen these supposed pessimists’ reports from 1950 predicting “doomsday” by 2000. Maybe you can link to the specific prediction you are referring to?
This historical summary from the American Institute of Physics might help, https://www.aip.org/history/climate/public.htm
Most of the work in the 50s–70s led the experts in the field to say, paraphrased, “there’s something serious going on here, and we’d better study it carefully ASAP and figure out how to mitigate our impact, or things could get bad.” The topic wasn’t really a serious concern to the general public until the 1980s, by which time there was starting to be broad agreement among experts. Since then, we’ve filled in a lot of additional details, and there is a strong “scientific consensus” that global warming is a real effect, caused by humans, which will have dramatic consequences if we continue down our current path.