There is measurable evidence that the earth has an ice age/non-ice age recurring cycle. 20000 years with ice age, 10000 years non-iceage. So yes the planet itself is in constant flux.
The idea that our actions as a tech species does not affect climate change is plain ignorant however. Herd animals cover wide territories because they will and do eat themselves out of house and home, so they look for greener pastures. Humans as a species have taken over the entire planet to the point that we no longer have greener pastures to turn too.
ie: the Mayan Indians of South America, changed their environment so much that their culture was no longer sustainable, it disappeared. They cut down so many trees that their farm lands became silted over.
Our current dilemma is very similar. We are cutting down trees at a fast rate. The rainforests of the world are disappearing. There is no more old growth forests left in America, except the Sequoias. Trees eat green house gases and expel oxygen. Animal life on this planet is a direct result from trees. Trees enmass are heat sinks and water sinks. Remove the trees and the heats stays in the atmosphere, water levels in the ocean increase. The artic and Antarctic icecaps are disappearing, this increases water levels.
We today will not pay the price for our species voracious behavior. We will be our own extinction event in the future if we as a species refuse to open our eyes today. We need to step out of our animal behavior and step into a common sense approach as to how we use our earth's resources, or else we get what we deserve.
Extinction
Those that deny this the most are probably those that benefit the most in our society. History is full of examples where we impacted the environment locally. Now we cover the planet, we impact the environment globally. Common sense dictates..................... .......................