If that's a serious question, the answers are nothing and nothing. Ice ages have been relatively cyclical on the planet for a long time, and until our arrival, the plants and animals changed (in part) in response to these cycles, as well as continental drift, island biogeography, natural selection,and a few other factors.
But if anything, we should probably be entering a new 'ice age' at this point, and yet we are experiencing, year after year, record-breaking global temperature increases.
We've caused the desertification of much of northern Africa; we've eliminated mind-bogglingly large populations of animals (bison/passenger pigeon); we've created canals and waterways to join otherwise isolated watercourses; we've deforested and then reforested (with fewer species) enormous tracts of land; we've increased our population and its industrial/technological impact beyond anything imaginable; we've altered the temperature and salinity of the oceans and turned them into a plastics dump. 40 years ago, we took on our proven impact on the ozone layer and actually undid much of the damage through marketing, policy and legislation. I cannot understand why it would be hard to imagine that we might, after all of that, be having a global impact on cllimate.
Ah, dang. You tricked me into it, didn't you?
brent