Human-caused climate change is due to rising levels of carbon dioxide and other heat-trapping gases. These gases, predominantly carbon dioxide, have warmed the earth and are already causing wide-ranging impacts, from rising sea levels, to melting snow and ice, to more drought and extreme rainfall. 
Greenhouse gases goes beyond carbon dioxide. Methane, nitrous oxide, and refrigerant gases are also greenhouse gases. To make things easier to express, there is the term C02e, which means carbon dioxide equivalent. C02e is the total climate change impact of all greenhouse gases caused by a behavior or product and is expressed in terms of carbon dioxide. 
It is impossible to exist without having some effect on the planet. The simple choices that we make can have small or large C02e consequences. Understanding C02e impact in the things that we do and buy, whether they are online, in the local store, or across the world can help us to make big changes in our carbon impact, while still allowing ourselves to not sweat the small stuff, to just relax and enjoy life.