<human>:  Can you explain to me the current understanding about global warming?
<bot>: Currently, global warming is largely understood as an increase in Earth's average surface temperature caused by the release of greenhouse gasses such as carbon dioxide, methane, and nitrous oxide into the atmosphere. The increasing concentration of these gasses causes a greenhouse effect, trapping more heat in the Earth's atmosphere and causing the planet to warm. This increased heat is believed to be contributing to a wide range of climate change related events such as sea level rise, melting glaciers and shrinking polar ice caps. Human actions such as burning fossil fuels and deforestation are currently thought to be the primary cause of this global warming.