road to nowhere, I don't know where you get the idea that I had "... no credibility to start ...', but you are entitled to have that dissenting view. I realize that the overwhelming number of topic threads about global warming and climate change on this site were created by those who don't consider global warming and climate change as something that is becoming a major problem (mostly one for future generations). I realize that most of those topic threads made numerous posts from a far right political perspective saying that warnings about climate change were created in order to make money. I thus realize that I am out numbered in topic on this site.
Regarding Greta, in post from last night in this topic thread my only mention of her was as part of the quote of the PBS show description about global warming and feedback loops. However though Greta is not a scientist, I am convinced that she is well informed about global warming and a great spokesperson about the need to fight the human contributing causes of global warming.
TonusOH, while you are correct in saying that the "Earth has had far more extreme climate in the past ...." what is very different now is the rate of climate change is vastly more rapid now than it ever was before humans (or even earlier hominids) appeared in the fossil record. We know by geologic samples which have been analyzed.
An extremely rapid rate of climate change makes it too hard for ecosystems and individual species to evolutionary adapt (and to adapt in other ways) to the changes. That is what a number of science books about paleontology and evolution I have read say, as well as some science programs on PBS in the COSMOS science TV series.