<human>:  Please explain the concept of global warming.
<bot>: Global warming is the long-term warming of the planet due to the increasing levels of greenhouse gases, such as carbon dioxide, in the atmosphere. These gases trap heat from the sun and cause the Earth’s average temperature to rise. As the Earth warms, more precipitation, heat waves, and drought are expected and global sea levels will continue to rise. While natural processes, such as variations in the Earth's orbit and volcanic eruptions, can affect the climate, it is the burning of fossil fuels that is the primary driver of global warming.