This question is at the origin of the debate that has gone for a while but that in the past two years has concluded that the current changes in our climate are mainly due to anthropogenic emissions.

Everyone can agree that the earth cycle has gone through some periods of ice age but what it is also very obvious is that we humans have affected the emissions of carbon dioxide since the european industrial revolution. These emissions have a direct impact in the concentration of greenhouse gases in the atmosphere which has a direct impact on the earth's greenhouse gas effect resulting in an increase in the temperature. In my opinion these are direct relations to conclude that human kind has had an impact on the climate.

I would recommend to read the new IPCC report where details on the reasoning can be found: IPCC REPORT