  The anthropogenic emissions of greenhouse gases (GHG) are widely realized as
the predominant drivers of global warming, but the huge and increasing
anthropogenic direct heat emissions (AHE) has not gained enough attention in
terms of its role in the warming of the climate system. Based on two reasonable
assumptions of (1) AHE eventually transfers to the Earth energy system and (2)
the net warming is only driven by the net radioactive forcing (RF) from either
GHG or other causes, we analyzed the role of AHE in global warming. The mean
annual total AHE of the four main sources including energy consumption,
residual heat of electricity generation, biomass decomposition by land use and
cover change (LUCC) and food consumption was estimated to be 4.41*10^20 J in
1970-2010, accounting for 6.23% of the net annual heat increase of the Earth
reported by IPCC AR5 for the period. The mean annual radioactive forcing (RF)
by AHE was up to 29.94 mW m^(-2) globally in 1981-2010, less than the annual
net increase of total GHG (34.80 mW m^(-2)) but more that of CO2 (24.43 mW
m^(-2). The results suggested that AHE played a great role in global warming,
urging us to pay more attention to DHE for a better evaluation of RF and more
reasonable energy policy including non-GHG energy in the future (Keywords:
climate change, anthropogenic direct heat emission, energy, radioactive
forcing, heat balance, global warming).
