széndioxidegyenérték

Széndioxidegyenérték, often abbreviated as CO2e, is a measure used to compare the global warming potential of different greenhouse gases. It is expressed in units of mass, typically tonnes of CO2e. The concept allows for the quantification of the impact of various gases on climate change in a standardized way, relating them back to the warming effect of carbon dioxide.

Each greenhouse gas has a different capacity to trap heat in the atmosphere, known as its global warming potential (GWP). The GWP is calculated relative to carbon dioxide over a specific time horizon, usually 100 years. For example, methane (CH4) has a GWP of 28-34 over 100 years, meaning that over that period, one tonne of methane traps as much heat as 28-34 tonnes of carbon dioxide. Nitrous oxide (N2O) has a GWP of 265-298.

To calculate the CO2e of a specific emission, the mass of the gas emitted is multiplied by its GWP. For instance, if one tonne of methane is released, its contribution to global warming is equivalent to 28-34 tonnes of CO2. This metric is crucial for international climate agreements, carbon footprint accounting, and setting emission reduction targets, as it provides a unified way to assess and manage the climate impact of diverse emissions. By converting all greenhouse gas emissions to a common CO2e unit, policymakers and industries can better understand their overall contribution to climate change and prioritize mitigation efforts.