Although the demand on agriculture to produce food could double by 2050, changing diets will expand the global demand for protein even faster. Canadian livestock producers will likely expand in response to this market opportunity. Because of the high greenhouse gas (GHG) emissions from animal protein production, the portion of this protein demand that can be met by pulse crops must be considered. The protein basis for GHG emission intensity was assessed for 2006 using a multi-commodity GHG emissions inventory model. Because arable land is required for other agricultural products, protein production and GHG emissions were also assessed on the basis of the land use. GHG emissions per unit of protein are one or two orders of magnitude higher for protein from livestock, particularly ruminants, than for protein from pulses. The protein production from pulses was moderately higher per unit of land than the protein from livestock. This difference was greater when soybeans were the only pulse in the comparison. Protein from livestock, especially ruminants, resulted in much higher GHG emissions per unit of land than the protein from pulses. A shift towards more protein from pulses could assure a better global protein supply and reduce GHG emissions associated with that supply.