Combustion of forest and grassland vegetation contributes to atmospheric pollution and rising greenhouse gases concentrations. Remotely measuring the energy radiated during natural fires has been suggested as a method for enhancing current emissions estimates. When made from satellites, such measures can potentially provide important new information on large-scale biomass combustion rates, which relate directly to the production of emissions. EOS-MODIS now makes such observations globally, multiple times per day. Using small experimental fires observed with a field spectro-radiometer we present the first evaluation of the relationship between time-integrated fire radiative energy and total mass of vegetation combusted. Results indicate a linear relationship (r2 = 0.78) for fire sizes varying over almost two orders of magnitude. Further information on the rate and intensity of burning is contained within the emission spectra. The results support the continued investigation of fire radiative energy as a new tool to enhance biomass burning emissions inventories.