Renewable energy systems produce zero or few greenhouse gas emissions while they are being used and only small amounts during the manufacturing of equipment or fuels. Renewable sources of energy also produce few air and water pollutants, wastes and land disruption. If renewable energy equipment is carefully located (e.g., solar collectors on buildings or biofuel crops on marginal land) then there are few land use conflicts.
In comparison, conventional energy generation, transportation and energy-intensive industries are responsible for most of the human-created air pollution and the planet's greenhouse gas emissions. Fossil fuel and uranium exploration, extraction and production also have major impacts on land and water resources.