CO 2, by definition, has a GWP of 1 regardless of the time period used, because it is the gas being used as the reference.GWPs provide a common unit of measure, which allows analysts to add up emissions estimates of different gases (e.g., to compile a national GHG inventory), and allows policymakers to compare emissions reduction opportunities across sectors and gases. The time period usually used for GWPs is 100 years.
The larger the GWP, the more that a given gas warms the Earth compared to CO 2 over that time period. Specifically, it is a measure of how much energy the emissions of 1 ton of a gas will absorb over a given period of time, relative to the emissions of 1 ton of carbon dioxide (CO 2). The Global Warming Potential (GWP) was developed to allow comparisons of the global warming impacts of different gases. Two key ways in which these gases differ from each other are their ability to absorb energy (their 'radiative efficiency'), and how long they stay in the atmosphere (also known as their 'lifetime'). Different GHGs can have different effects on the Earth's warming. Greenhouse gases (GHGs) warm the Earth by absorbing energy and slowing the rate at which the energy escapes to space they act like a blanket insulating the Earth.
