If you walk on the beach, you are breathing in oxygen rich air and breathing out carbon dioxide rich air. Carbon dioxide (“carbon”) is a colorless greenhouse gas, meaning that the sunlight goes through it. Once the sunlight hits the ground it is converted into heat. Such heat from the ground however, is absorbed by carbon dioxide thereby trapping the heat in the air. Same as a greenhouse. That‘s the reason carbon dioxide is called to be a greenhouse gas.
Now, the carbon dioxide you exhale is also absorbed by the trees in the park converting it into wood, the carbon cycle of life. Wood is stored carbon.
If you now drive a car to the mall, your car burns fossil fuels and converts them into carbon dioxide. And everything you buy in the mall has been produced with fossil fuels releasing carbon dioxide into the air, referred to as carbon emissions.
Because it is so much now, the trees in the world cannot absorb it all, and, hence carbon emissions accumulates in the atmosphere for over 100 years now, causing a hotter climate.
Now, for every product you can calculate the amount of carbon it costs to produce it. This number is the so called carbon footprint of a product. As en example, if you produce a 10 oz chocolate bar, it could easily have a carbon footprint of half a pound.
Now, imagine the chocolate bar has been produced with green power only, with 100% green and clean renewable energy. These products do not have a carbon footprint anymore. They are zero emission products (ZEPs) or zero-footprint products – and the earth‘s atmosphere is clean again!