Earth is a solar-powered planet. Solar power is heat and light from the sun, and it is the source of almost all of the energy used on Earth. Plants have been using energy from the sun for millions of years. They change the sun’s light energy into carbohydrates through a process called photosynthesis. Carbohydrates are substances that store energy in a form that can be used by all living things. When people and animals eat plants or eat other animals that have eaten plants, the sun’s energy stored in plants is passed on. That’s how people and plants, birds and butterflies, wolves and whales, fish and frogs—almost all living things on Earth—get energy for life from the sun.
Millions of years ago, when ancient plants and animals died, sand, rock, and mud gradually accumulated on top of their bodies. Over time, heat and pressure turned their remains into coal, oil, and natural gas. We call those energy sources fossil fuels because they come from ancient plants and animals. When we burn fossil fuels to make electricity and to power our cars and trucks, we are using the energy from the sun that was stored in the bodies of organisms that lived millions of years ago.
Now we know that burning fossil fuels is causing problems on Earth. It contributes to air pollution and is the main cause of climate change. Gases released when we burn fossil fuels trap the sun’s energy close to Earth. Because of that, the global climate is getting warmer. That warming trend, in turn, is affecting other aspects of Earth’s climate. Climate is different from weather. Weather is what it’s like in a particular place at a particular time—how hot, cold, rainy, snowy or windy it is today, for example. Climate is about conditions over a very large area over a long period of time. A changing climate affects the lives of people, wildlife, and plants. In the future, for example, some kinds of birds may not be able to find food in the same places where they raise their young. That’s why it’s so important for everyone to take action to use less energy from fossil fuels and to find cleaner, “greener” sources of energy.
Photos: (t to b) Heidi Piccerelli/Audubon Photography Awards; ingimage.