- Solar power has been growing exponentially for years and will continue for a while allowing carbon usage to be phased out and maybe carbon capture done.
- The climate has changed naturally more than most people realise and life goes on. The sea is forecast to rise 60cm or so over this century but has risen ~120m over the last 20k years which was hardly noticed. (graph from wikipedia https://upload.wikimedia.org/wikipedia/commons/1/1d/Post-Gla...)
Also, why do you think the impact of past changes on a tiny group of humans living as hunter gatherers is of any relevance to 8 billion people living in the modern world (including, for example, in massive coastal cities?)
https://en.wikipedia.org/wiki/John_Christy https://en.wikipedia.org/wiki/Roy_Spencer_(meteorologist)
Spencer's view is that there is a natural climate change going on that just happens to coincide exactly with increasing greenhouse gases. Christy believes that climate change is real and partly anthropogenic but that it's just not going to be all that bad.
If your friends think that it's not happening, you can point them at the data that these two gather:
https://www.nsstc.uah.edu/climate/
They'd disagree with your friends that humans are not involved at all. But your friends could switch to the position that climate change just doesn't matter and it'll all be fine.