// [Attenborough's] talk of the “end of civilisation” and the mass extermination of species simply reminds me of the countless other scares I have endured in my lifetime promulgated by experts. //
I'll address the last part in a separate post, although it probably repeats points I've made elsewhere already, but for the first, it's worth noting that (a) plenty of species have already been made extinct by human activity, and (b) Climate Change certainly *does* threaten, if not the end of civilisation, then certainly a hefty blow to it. Probably the single most devastating period for life on the planet is the "Permian Extinction", which is heavily suspected to have been driven by Climate Change (among other factors), and which accounted for something close to 90% of all known species at the time. Even a period climate change a fraction as bad would therefore be very harmful.
I tend to agree that the worst predictions are better interpreted as warnings to avoid rather than accurate visions of what is to come, but even then they are useful. You could drive off a cliff! But, of course, there's no danger, as long as you remembered to hit the brake. Sometimes, it's good to have fears that are unfounded.