You have to provide proof for the claim that humans significantly alter the energy levels of the system. These things you mention have happened before without human interference.
Yes, and every time they happened before it was a mass extinction event. We have proved these things are caused by us. Through sataelite observations and isotope measurements.
Proving that humans do have a significant impact on climate change is not possible yet because we have way too little data. The warming right now could as well not be caused by humans.