Radiative forcing efficiency

The radiative effects of aerosols and gases strongly depend on where they are emitted. We have calculated the change in global direct radiative forcing per unit emissions of black carbon, organic carbon, and sulfate. These are available for download, after spatial averaging to the state and country level. The global gridded data are also available for download. Read about how these values are calculated.

  • Select a compound

    Global direct radiative forcing per unit emissions (mW m-2 Tg-1)

  • Select a compound

    Global direct radiative forcing per unit emissions (mW m-2 Tg-1)

  • Gridded global values at 2 by 2.5 degrees are available as a NetCDF file.

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  • Climate change can be dangerous for two reasons. First, if the rate of climate change is faster than we can adapt, then damages are likely to be substantial. Second, if the magnitude of climate change is very large, than the impacts are more costly to adapt to. It is important to consider both the rate of climate change, which can be reduced by focusing on short-lived species, and the overall magnitude of climate change, which can be mitigated by focusing on long-lived species.

    The radiative forcing values shown on the other tabs are distilled down to metrics to allow comparison of short-lived and longer-lived pollutants for understanding the rate and magnitude of climate change.

    TIRF50

    The Total Integrated Radiative Forcing (TIRF) is the sum total of the radiative impacts during a 50 year time period. For GLIMPSE, this metric converts a stream of emissions over a 50 year period, from 2005 -- 2055, to the total change in radiative forcing during the same 50 year period, 2005 -- 2055. For longer-lived pollutants that accumulate over time, emissions at the beginning of the 50 year period persist throughout the entire calculation, and hence have a larger effect than those emitted at the end of the period. For short-lived species that do not accumulate in the atmosphere, their impact is the same no matter when they are emitted.

    The TIRF50 is a useful metric for understanding the impact of both short-lived and long-lived climate forcers. For GLIMPSE, the spatially resolved radiative forcings shown on the other tabs are used to calculate this metric. Longer-lived species are included using parameterizations from IPCC.

    GWP100

    The Global Warming Potential is a measure of the amount of heat trapped by a greenhouse gas over a 100 year period. In contrast with TIRF, the GWP is calculated from the time of emission to 100 years in the future; radiative impacts after 2055 are included in this metric. Emissions occurring in the future have the same weight as those emissions nearer to the present. Because the GWP is calculated over a 100-year period, long-lived species have relatively larger impact than short-lived species.

    The GWP100 is a good metric for understanding the impact of emissions on the overall magnitude of climate change. Because the GWP100 is not sensitive to the timing of the emissions, the TIRF50 is a better metric for understanding the impact of emissions on the current rate of climate change.


Comments or Questions? Contact: Rob Pinder