Energy efficiency and greenhouse gas emissions are closely linked. This paper reviews agricultural options to reduce energy\nintensities and their impacts, discusses important accounting issues related to system boundaries, land scarcity, and measurement\nunits and compares agricultural energy intensities and improvement potentials on an international level. Agricultural development\nin recent decades, while increasing yields, has led to lower average energy efficiencies when comparing the 1960s and the\nmid 1980s. In the two decades thereafter, energy intensities in developed countries increased, but with little impact on greenhouse\ngas emissions. Efficiency differences across countries in the year 2000 suggest a maximum improvement potential of 500 million\ntons of CO2 annually. If only below average countries would increase their energy efficiency to average levels of the year 2000, the\nresulting emission reductions would be below 200 million tons of CO2 annually.