Albedo changes caused by future urbanization contribute to global warming

The replacement of natural lands with urban structures has multiple environmental consequences, yet little is known about the magnitude and extent of albedo-induced warming contributions from urbanization at the global scale in the past and future. Here, we apply an empirical approach to quantify the climate effects of past urbanization and future urbanization projected under different shared socioeconomic pathways (SSPs). We find an albedo-induced warming effect of urbanization for both the past and the projected futures under three illustrative scenarios. The albedo decease from urbanization in 2018 relative to 2001 has yielded a 100-year average annual global warming of 0.00014 [0.00008, 0.00021] degrees C. Without proper mitigation, future urbanization in 2050 relative to 2018 and that in 2100 relative to 2018 under the intermediate emission scenario (SSP2-4.5) would yield a 100-year average warming effect of 0.00107 [0.00057,0.00179] degrees C and 0.00152 [0.00078,0.00259] degrees C, respectively, through altering the Earth's albedo. Albedo changes caused by projected future urban land expansion will contribute to global warming without proper mitigation. This warming effect will be larger under higher emission scenarios than under lower emission scenarios.

Automated summary

The replacement of natural lands with urban structures has led to a decrease in albedo, contributing to global warming. Future urban land expansion without proper mitigation will further exacerbate this effect.