The Earth has experienced numerous cycles of climate change. Believable. Geology, ice ages, vast prehistoric lakes in what is now desert, fossil records, etc. support this.
We are in a cycle of climate change now. Believable. It’s happened before, it well could be happening now.
For the first time in the history of the universe, climate change is now caused by human activity. OK, for this you’re going to need proof of a much higher order.
“We are in a cycle of climate change now.”
We always are, always have been and always will be until the sun goes dormant or dies/explodes etc.