Global warming is caused by increased levels of greenhouse gases like carbon dioxide and methane that are released into the atmosphere by human activities such as burning fossil fuels and deforestation. This causes less heat to escape Earth, increasing temperatures. Current effects include stronger hurricanes, rising sea levels, and shifting animal habitats. Future effects may include more extreme weather, flooding of coastal cities, and species extinction if warming continues unchecked. Individual actions like using less energy and alternative fuels can help reduce the impacts.