At this time, the world's energy supply and the protection of the ring. The source of carbon-dense energy, the source of the old energy, such as coal, oil, gas and so on.

Coal is rich in the earth, and it has been formed over the years. In the ancient world, its use was wide, and everything depended on it for cooking and smelting. However, its combustion also released more carbon oxides, caused gas pollution, and helped the temperature rise, and the disease of the ring gradually appeared.

Oil is also the most important energy of the world. Cars and boats sail, and they are mostly powered by it. However, its adoption and use also have various disadvantages. When it is exploited, it may damage the ecology of the land; when it is used, it emits carbides, pollutes the air and disturbs the balance of air.

As for gas, although it is cleaner than coal and oil, it is also a source of carbon-dense energy. Although its combustion is less polluted than the first two, it accumulates over the years, and the carbon quality emitted is also harmful to the ring.

Today's wise people seek to change their energy. They want to reduce the source of carbon-dense energy, and generate clean energy and regenerative energy, such as solar energy, wind energy, and water energy. It is hoped that new energy will replace the old source, so that the ring will be purified, the gas will be purified, and the world will be sustainable.