I think it's fairly obvious that climate change presents a tremendous threat (I assume that's what the parent is on, it's flagged so I can no longer see it), but a _billion_ is a gross overstatement. I'd recommend checking out Climate Feedback[0], a website I like to check on that is a panel of climate scientists basically reviewing claims on climate change. 99% are them reviewing climate denial, but some in there are reviewing claims overstating the impact of climate change.
[0]https://climatefeedback.org