Carbon emission trading is a way to help reduce the amount of carbon dioxide that goes into the air. It works by making it so that companies have to buy or sell a special kind of sticker called a carbon credit.
Companies that produce a lot of carbon dioxide, like factories and power plants, have to buy these credits. That means they have to pay money for every ton of carbon dioxide they produce.
The companies that produce less carbon dioxide, like those that use renewable energy, get credits they can sell to other companies. That's how they make money while reducing their carbon footprint.
The idea is that when companies have to pay for their carbon emissions, they'll start to find new ways to produce their products without releasing so much carbon dioxide. That way we can help protect our planet from the negative effects of too much carbon dioxide in the air.