Quite obviously solar radiation affects the overall climate of Earth far more than human activity does. If the sun suddenly went dead, the temperature on Earth would plummet to near absolute zero ( -459º FF or -273º C). All water vapor in the atmosphere would condense as ice and snow, and we would be a giant, dead ice ball.
That said, this question is dangerously deceptive, because while solar radiation has far more influence, that is not to say we should ignore human influence. Human activity only has to add 2 or 3º C to the global temperature to do great harm. If we keep pouring carbon dioxide and methane into the atmosphere and warm the global average temperature by as little as 3º Centigrade, we may set off a cascade of methane releases from previously frozen tundra and from methane clathrates in the ocean depths. Methane is more than 20 times as effective as Carbon Dioxide as a greenhouse gas, and there are as many as 2500 gigatonnes of methane clathrates in the Earth’s oceans and another 400 gigatonnes in arctic permafrost. If global warming starts the mass release of that, we would be looking at a runaway climate change we would be powerless to halt, and that could warm the average temperature of earth by 12 to 15 ºC (53.6 ºF to 59 ºF ) as it has done in the Earth’s past and could also create massive dead zones in the oceans. Think 110 ºF is too damn hot? How would you like a day that hit 170 ºF?
Ambient temperature has more influence on the temperature inside your home than your home heating system does. Even in the coldest winter day, the ambient temperature outside is FAR warmer than absolute zero. But would that mean that you should run your heater full tilt whether it is 30 below zero outside or 110 ºF in the shade? Such a suggestion would be absurd. And so would ignoring man-made climate change because it is less of a factor in Earth’s temperature than the sun’s radiation is.