Reducing uncertainties in climate models

Abstract

Here, we report radiative forcing is a fundamental quantity for understanding both anthropogenic and natural changes in climate. It measures the extent to which human activities [such as the emission of carbon dioxide (CO 2 ), see the image] and natural events (such as volcanic eruptions) perturb the flow of energy into and out of the climate system. This perturbation initiates all other changes of the climate in response to external forcings. Inconsistencies in the calculation of radiative forcing by CO 2 introduce uncertainties in model projections of climate change, a problem that has persisted for more than two decades. The explicit calculation of radiative forcing and a careful vetting of radiative transfer parameterizations provide a straightforward means to substantially reduce these uncertainties and improve the projections.