There are many different greenhouse gases of which carbon dioxide is the most widely known. Different greenhouse gases affect the climate in different ways. Some stay in the atmosphere for a long time but do not cause so much warming per kg emissions, like carbon dioxide. Others, like methane, heat the earth a lot, but do not stay very long in the atmosphere. There is an exchange rate of sorts, that makes comparison of the different gases possible. The exchange rate expresses how many kg of carbon dioxide emissions that warms the climate equally as 1 kg of another greenhouse gas. The exchange rate is called Global Warming Potential and is typically abbreviated GWP. By knowing the GWP of different gases the total climate impact of a product can be condensed into one single unit: kilograms of carbon dioxide equivalents (kg CO2e).