Global warming is the long-term rise in Earth's average surface temperature caused by human activities like burning fossil fuels, deforestation, and emitting greenhouse gases into the atmosphere, such as carbon dioxide and methane. These gases trap heat from the sun, causing the planet's temperature to increase, leading to several environmental impacts, including melting glaciers, sea-level rise, more frequent and severe natural disasters like hurricanes, droughts, wildfires, and climate refugees.