We may be contributing to it in a big way with our CO2 output but not a massive one, what we are doing to cause major problems is cutting down trees and destroying vegetation, the very stuff that cleans the CO2 from the atmosphere and of course provides us with our much needed oxygen.... only mankind could destroy the one thing it needs to actually breath and "depollute" the atrmosphere!
The Earth has cycles, we are already something like 5 to 6 thousand years overdue an ice age and that's due to our CO2 output warming the Earth we are now heading into a period of heating which will melt the ice caps, cause massive flooding and even more heat due to the lack of snow/ice reflecting the suns heat... not good for us or marine life due to the masses of freshwater entering the coeans.
The Sun is in a cooling period, it is not giving off the amount of heat it did, this should have taken us into another ice age, it hasn't, the atmosphere is in turmoil, the troposhere (where we live) is heating up alrmingly whereas the Stratosphere is cooling (due to the Sun being in a cooling cycle) if it was just down to the sun as some have claimed then both "spheres" would be cooling.
Natural cycle. There is no shortage of real climate scientists - who are being conveniently ignored - on the tube of you explaining about weather and sunspot cycles. It's about a 200 year cycle that we're on.
Have a look at these records from a few hundred years ago.