Future changes in the atmospheric energy cycle were estimated by using 12 climate models from the fifth phase of the Coupled Model Intercomparison Project (CMIP5) and mass‐weighted isentropic zonal‐mean framework. In this framework, the zonal‐mean available potential energy (AZ) is converted to the zonal‐mean kinetic energy (KZ) through mean‐meridional direct circulations, and KZ is converted to the wave energy (W), the sum of eddy available potential energy and eddy kinetic energy, through wave‐mean flow interactions. The comparison between the late 21st century in a high emission scenario and the late 20th century in the historical scenario indicates a significant increase in AZ and KZ in winter in the Northern Hemisphere (NH) and the Southern Hemisphere (SH). The wave energy significantly decreases in the NH winter but slightly increases in the SH winter. In the NH winter, the stationary wave energy significantly decreases, and the transient wave energy shifts poleward. Global warming reduces the baroclinic instability wave activity, which suppresses the upward Eliassen‐Palm flux and wave‐induced extratropical direct circulation. It decreases the dynamic energy conversion rates C(AZ, KZ) and C(KZ, W). On the other hand, the diabatic wave energy generation rate (QE) is projected to increase, particularly in the SH. The future W change is consistent with the change in the sum of C(KZ, W) and QE. Changes in both the dynamical energy conversion associated with wave‐mean flow interactions and the generation of eddy available potential energy associated with diabatic heating processes are necessary to explain the wave energy change. Plain Language Summary Atmospheric energy can be divided into three components: the zonal (averaged along a latitudinal circle) kinetic energy, zonal potential energy, and wave energy, which is the sum of eddy kinetic and potential energy. We have investigated future changes in energy flow between these components using a novel coordinate system with a better representation of wave dynamics. A comparison between the late 20th century and late 21st century in a high emission scenario shows that the two zonal components increase, whereas the wave energy significantly decreases in the Northern Hemisphere winter and slightly increases in the Southern Hemisphere winter. Global warming suppresses energy conversions between the components by decreasing a pole‐to‐equator temperature difference. In contrast, wave energy generation by radiation and latent heat increases particularly in the Southern Hemisphere winter. We have found a positive correlation between changes in the wave energy and changes in the sum of the energy conversion and generation, which will provide further insights into the mechanism of future changes in high‐ and low‐pressure patterns and winter monsoon. Key Points The wave energy will significantly decrease and slightly increase in winter in the Northern and Southern Hemispheres, respectively Global warming suppresses the wave‐mean flow interactions and reduces the dynamic energy conversion rates The future change in the wave energy is consistent with the change in the sum of its dynamic conversion and diabatic generation rates