There was ENORMOUS climate change for billions of years on earth before homo saps ever showed up. How did they/we make things WORSE?

The largest climate-change so far experienced by humans was the nominal end about 11000 years ago, of the Last Glacial Maximum of the present Ice Age.

It hardly affected humans and our Neanderthal brethren if they were still about by then, because those around at the time were fairly few in number, widely spread, highly nomadic, and so could move relatively easily to respond to what in human terms were slow changes.

The difference for people between then and now is that our modern population and its drain on natural resources and room is far, far larger; our societies and social systems are far, far more complicated and interdependent; and these are growing rapidly.

The difference geographically between then and now is that the Ice Age LGM thaw was rapid in its own way but not too rapid for people to handle. If the weather-systems and sea-level had changed rapidly enough for a few generations to notice, they would have not understood it, but would have coped with it. What's happening now is that we are accelerating the rate of change; and have reversed the approach. We understand it now, but will find it extremely difficult to cope with it.

Left entirely to Nature the general rate of change would be slowing, albeit with assorted smaller fluctuations in fairly regular but complex cycles.

We also have an unfortunate tendency to put ourselves in the way of Nature then wonder what happened when Nature does its own thing.

Some people try to blame the present climate change on those natural smaller fluctuations, but those don't match. Anthropocentric climate change was actually being forecast about 100 years ago. It was based then on the contemporary rate of coal consumption, when the mineral was the developed world's primary fuel, and put the danger times a lot further into the future. Since then our world-wide population and overall fuel consumption had multiplied considerably; bringing the threat much closer.