There is no need to substantiate it, it is plain pure logic. The climate will always change. We can influence it a bit, but definitely a lot less than we having giving ourselves credit for. More than that, we don't have enough data to understand how the climate would change by itself, without human influence. The same way there is night and day, winter and summer, planet Earth might be subject to other climate variations that we don't have a clue.

One thing I know for sure: if the population is growing, the Earth is becoming better for human-life, not worse. I'll be concerned about climate change when the population starts to shrink but we are way far from that.