Global warming is caused by a combination of natural and human factors. However, the current era of global warming is directly attributable to human activity, specifically to our burning of fossil fuels such as coal, oil, gasoline, and natural gas, which results in the greenhouse effect. The greenhouse effect is a natural process that occurs when certain gases in the Earths atmosphere trap the suns heat and stop it from leaking back into space, causing global warming. The main driver of climate change is the greenhouse effect, and human activities are increasing the concentrations of some of these gases in the atmosphere, including carbon dioxide (CO2), methane, nitrous oxide, and fluorinated gases.

Other human activities that contribute to global warming include deforestation, which reduces the number of trees that absorb carbon dioxide, and the production of livestock, which produces methane. Natural causes, such as changes in solar radiation or volcanic activity, are estimated to have contributed less than plus or minus 0.1°C to total warming between 1890 and 2010.

In summary, global warming is caused by the increase of greenhouse gases in the atmosphere, which is primarily due to human activities such as burning fossil fuels and deforestation.