Regional patterns of change appear to be linked more closely to internal variability, particularly during the 1930s. Our current “best guess” is that the global mean changes in temperature, including the 1940-1970 cooling, are quite closely related to the forcings. Even then, any discrepancy might be due to internal variability (related principally to the ocean on multi-decadal time scales). Matching up what really happened with what we might have expected to happen requires taking into consideration all the forcings, as best as we can. Some forcings - sulfate and nitrate aerosols, land-use changes, solar irradiance, and volcanic aerosols, for instance - can cause cooling. In the real world, climate is affected both by internal variability (natural internal processes within the climate system) and forcings (external forces, either natural or human-induced, acting on the climate system).
To support our nonprofit environmental journalism, please consider disabling your ad-blocker to allow ads on Grist.
0 kommentar(er)
