The latent heating feedback effect on storm tracks in current and future climates

Extratropical storms release latent heat as they transport warm, moist air poleward and upward. That latent heating feeds back on storms by intensifying individual cyclones and by altering the environmental conditions for the growth of storms, constituting a latent heating-dynamics feedback. As the climate warms, storm-track latent heating increases, but the role of this feedback in a future climate remains unclear. Using atmospheric general-circulation model experiments that separate the coupled heating-dynamics feedback from climatological changes in latent heating, we show that this feedback plays a leading-order role in intensifying storm tracks under +4 K warming. The feedback increases lower-tropospheric storm intensity, compensating for reduced baroclinicity, while its upper-tropospheric effect is seasonal: amplifying summer eddies but damping winter ones. The feedback is critical for storms that grow in moist environments, typical for summer and warmer climates, underscoring the need for accurate representation of moist processes in climate models.