The sequence of event for the evolution of the atmosphere: 1. meteorite bombardment 2. Volcanic Outgassing 3. Oceans Form 4. Banded Iron Formations Created 5. cyanobacteria evolve 6. Oxygen increases in atmosphere 7. Eukaryotes evolve
The increase of carbon dioxide in the atmosphere creates a greenhouse effect.
To explain this usually some sunlight is reflected back into space while some is absorbed by the earth keeping the planet warm. However the increase in greenhouse gases such as carbon dioxide prevent the light from reflecting back into space and this light becomes trapped causing the earth to heat more then it should. You can almost think of the trapped heat from the greenhouse gases as a blanket around the earth trapping the heat in.
