COväljaheitseid

COväljaheitseid, often shortened to CO2e, is a unit of measure used to express the global warming potential of various greenhouse gases in a single, comparable value. It represents the amount of carbon dioxide that would have the equivalent warming impact of a given amount of another greenhouse gas over a specified period, typically 100 years.

Different greenhouse gases have varying abilities to trap heat in the atmosphere and persist for different lengths of time. For instance, methane (CH4) is a more potent greenhouse gas than carbon dioxide over a shorter timeframe, but it breaks down more quickly. Nitrous oxide (N2O) is also more potent than CO2 and has a longer atmospheric lifetime. By converting the emissions of these other gases into their CO2e equivalent, it becomes possible to aggregate and compare the total climate impact of different activities, sectors, or nations.

The calculation of CO2e involves multiplying the mass of a greenhouse gas by its Global Warming Potential (GWP) value. GWPs are determined through scientific consensus and are periodically updated. For example, if a gas has a GWP of 25, then one ton of that gas has the same warming effect as 25 tons of carbon dioxide over 100 years. This metric is crucial for climate reporting, policy development, and target setting, allowing for a standardized assessment of contributions to climate change.