The severity of climate change will be determined mainly by how much, and how soon, we reduce our fossil fuel use and embrace clean, renewable energy sources. Renewable sources of energy are virtually inexhaustible and are naturally and quickly replenished. Switching to clean, renewable energy will bring us cleaner air and water, while improving human health and increasing energy security. It is fuel-free, reliable, silent, and durable. Solar thermal energy uses technologies and building-design to warm our houses, heat our bathwater, and power solar cookers by trapping heat from the sun.
Wind is the world's fastest growing energy source.
Biomass is humanity's oldest source of renewable energy. Produced by plants through photosynthesis, it is stored in organic matter such as wood, agricultural wastes, and animal wastes. Biomass can be converted into liquid or gaseous fuels, or it can be burned to generate electricity. Geothermal power is a form of renewable energy that uses natural heat from the Earth's core to warm buildings and generate electricity. Small-scale hydropower harnesses the energy in flowing water.