The issue of global warming is all too much an emotional issue that is decided by political alignments. Even some of those who vehemently decry burning fossil fuels because they increase carbon dioxide levels don't understand the 8th grade Earth Science behind it. Even fewer of the 'naysayers' do.
Earth transforms sunlight's visible light energy into infrared light energy, which leaves Earth slowly because it is absorbed by greenhouse gases. As greenhouse gases increase, this radiant energy escapes more slowly. This raises the Earth's overall temperature.
The Greenhouse Effect:
"The exchange of incoming and outgoing radiation that warms the Earth is often referred to as the greenhouse effect because a greenhouse works in much the same way."Incoming UV radiation easily passes through the glass walls of a greenhouse and is absorbed by the plants and hard surfaces inside. Weaker IR radiation, however, has difficulty passing through the glass walls and is trapped inside, thus warming the greenhouse. This effect lets tropical plants thrive inside a greenhouse, even during a cold winter.
"A similar phenomenon takes place in a car parked outside on a cold, sunny day. Incoming solar radiation warms the car's interior, but outgoing thermal radiation is trapped inside the car's closed windows."
A More Detailed Explanation of the "Atmospheric Greenhouse Effect":