"Overwhelming observed scientific evidence shows that climate has changed back and forth for a very long time."
Sure. But lets put that in perspective: https://xkcd.com/1732/
"Whatever is done about carbon emissions it will continue to change. We cannot rely on stable climate, nor on fixed sea levels."
Those are rapidly changing due to us. If we were not warming the planet then they would change over thousands of years across ice ages. Not like now across decades due to anthropomorphic global warming.