GWP

GWP, or Global Warming Potential, is a metric used to compare the climate impact of different greenhouse gases relative to carbon dioxide over a specified time horizon. The most commonly cited value is GWP over 100 years (GWP100): a dimensionless number indicating how much warming a mass of a gas would cause during that period compared with the same mass of CO2. The concept allows emissions of different gases to be expressed as carbon dioxide equivalents (CO2e) for easier aggregation in inventories and policy analysis.

GWP depends on the gas's radiative efficiency and atmospheric lifetime; gases with higher radiative forcing or longer lifetimes generally have higher GWP values, but the ranking can change with the chosen horizon. For example, methane has a relatively high GWP over 100 years, while some shorter-lived gases may have high GWP on shorter horizons. Values are provided by assessments such as the IPCC and are updated with new scientific understanding.

Uses include life cycle assessment, national reporting, and sector-specific policymaking. GWP is not a perfect measure: it abstracts away timing of emissions, non-radiative effects, and interactions within the climate system, and depends on horizon choice and baseline assumptions.

Another widely used meaning of GWP is Gross Written Premium in the insurance industry. It is the total premiums written by an insurer on contracts during a period, before deductions for reinsurance and premium ceded to reinsurers. GWP indicates business volume but not profitability, which requires net premiums written and other expense metrics.