What would happen if the sun went out tomorrow?
Our planet would cool (though there would be residual warmth for a while due to our core providing geothermal energy) and eventually we would end up being a lifeless rock.
What does that have to do with Climate Change though? That's like saying "If the sun doesn't shine on my conservatory, it is cold during the day! Therefore the heaters I have in there can't possibly have an effect on the temperature"