What might cause the average temperature of Earth to increase?
1 Answer
Quite a number of factors including; increased output from the sun, orbital variations that provide more incoming radiation, global warming events (natural and human).
Explanation:
The sun's output has been slowly increasing over the past 3 billion years and this is slowly increasing the average Earth's temperature. Milankovich orbital variations also push the Earth into cooling and warming events as less or more incoming solar radiation hits the northern hemisphere in particular. Natural global warming events can be set of by massive volcanic eruptions that spew billions of tonnes of CO2 into the atmosphere; thereby strengthening the natural greenhouse effect. Humans are also causing another un-natural global warming event now through the burning of fossil fuels.