Renewable and nonrenewable energy sources differ in their availability and environmental impact. **Renewable energy** comes from sources that replenish naturally and are sustainable, such as **solar**, **wind**, **hydropower**, **geothermal**, and **biomass**. These sources have minimal environmental impact and help reduce greenhouse gas emissions. **Nonrenewable energy**, including **fossil fuels** like **coal**, **oil**, and **natural gas**, and **nuclear energy**, is finite and depletes over time. Burning fossil fuels releases **carbon dioxide** and other pollutants, contributing to climate change and environmental degradation. While nonrenewable sources currently dominate global energy, transitioning to renewables is crucial for long-term sustainability and environmental health.