Energy systems are directly vulnerable to climate change. Final energy consumption is temperature sensitive, with multiple fuels providing space heating in cold seasons, and electricity overwhelmingly providing space cooling in hot seasons. Rising temperatures reduce demand for cold-season heating--and derived demands for multiple energy carriers, while increasing demand for hot-season ventilation and cooling--and derived demands for electric power. Previous research has raised concerns that, circa 2050, these adjustments substantially increase the demand for total energy, and especially electricity, globally and in most countries (De Cian and Sue Wing 2019; Van Ruijven et al, 2019). However, these findings rely on empirical models of energy demand that are estimated at coarse spatial and temporal scales, and are limited in their ability to capture seasonal and geographic heterogeneity in consumers' energy demand responses to varying temperatures.

Here we demonstrate very different implications for the impacts of mid-century temperature increases based on empirical models estimated on a novel dataset of hourly electric load in 36 world cities. Temperate cities exhibit the nonlinear asymmetric V-shaped response of electricity demand to temperature found by previous empirical studies of the US and Europe (Auffhammer et al 2017; Wenz et al 2017), while tropical cities' responses are mostly linear and less temperature-sensitive. We develop a novel technique to construct temporally downscaled hourly temperature series from daily climate model projections, resulting in current- and mid-century temperature distributions that we couple with our demand responses to project the impacts on total and peak demand. RCP8.5 warming induces larger shifts in temperate cities ' hourly temperature distributions (4-8 ºC, versus 1-3 ºC in tropical cities). Consequent changes in total annual electricity use are smaller than previously found, with 14 cities (mostly at mid latitudes) experiencing increases of <1%, 11 cities (mostly in the tropics) experiencing increases of 1-4% and an equal number experiencing overall reductions. By contrast, peak electricity use grows ubiquitously, with demand in two-thirds of cities (mostly in mid latitudes) rising by 7-17%, and smaller increases concentrated in the tropics.