Why should we know about carbon footprints?
Carbon plays a crucial role in the environment.
Today, especially with CO2 in the news being blamed for global warming its more important than ever to know your carbon footprint. Your carbon footprint is essentially how much "carbon" you release into the environment each year. As a whole, we as humans emit around 12 gigatons of carbon per year. We emit that in a variety of different ways however most of it ends up in the atmosphere where it becomes a contributor to global warming.
The main reason we want to know our carbon footprint then is because we can see how, as individuals, we are responsible for putting carbon into the air even when we think we aren't really to blame.
Just to clarify, carbon is not a bad element. Its important to most of the life on Earth and had been around for eons in one form or another! We just want to limit how much we put in the atmosphere because that is what makes the Earth warmer which is a bad thing if the Earth gets too warm.