Both natural and man-made climate change are real things. They are not mutually exclusive. Natural green house gases do exist through things like evaporation and organisms releasing carbon dioxide and methane. However, human activity have significantly added to this to the point that is far above natural levels.
Just because natural climate change also exists doesn't mean that man-made climate change doesn't exist! As a kid in the 80s I remember feeling hot wind being a real rarity. I remember the first time I ever felt a hot breeze. I was out on the back porch playing with Robotech toys and a hot breeze hit me. I freaked out! I never knew that wind could be warm! Visiting countries like Malaysia and Singapore freaked me out too because I never knew that you could have entire days that could be so impossibly hot and humid. Nowadays it's not uncommon to experience these forms of tropical climates in Sydney in summer or even in late Spring or early Autumn! What was an uncommon thing in my childhood has become commonplace now in only a span of about 3 decades.
I lived in Japan in 1997 and I remember the monsoonal rainy season hitting in June. It was crazy. I was in Japan in late September in 2016 and experienced monsoonal rain! I turned to my tour guide and asked him why this weather was happening so late in the year and he replied 温暖化 (climate change). Japanese weather is usually pretty punctual but in less than 20 years I witnessed a major shift in their rainy season.
If people want to disprove climate change or the roundness of the Earth or gravity etc., then burden of proof applies. When you want to prove a widely accepted fact as being untrue then it's up to you to provide sufficient evidence to support your views. It is not the responsibility of others to prove you wrong - when your views are contrary to commonly accepted truths then they are essentially wrong by default.
The Ancient Greeks knew that the Earth was round. They also proved it. It was a given in Greek and Roman societies that the Earth was round. To suggest otherwise would make you look like what we describe in Latin as an "idiota."