Spatial and temporal variation of anthropogenic heat emissions in Colombo, Sri Lanka

Anthropogenic heat emissions (AHEs) should be accounted for when making city, neighbourhood, and building scale decisions about building design, health preparedness (e.g. heat stress), and achieving net zero carbon. Therefore, datasets with spatial and temporal variations are required for the range of global cities, including lower-middle income, low-latitude cities. Here we estimate the 2020 AHEs at 100 m resolution for Colombo, Sri Lanka. The city-wide annual mean is 5.9 W m⁻². Seasonal variations are very small linked to small temperature differences, unlike mid- and high-latitude cities. However, the diurnal range of 17.6 to 1.8 W m⁻² has three distinct peaks (cf. two often found in mid-latitude cities). Transport, metabolic and building related emissions account for 35, 33, and 32% of the total emissions, respectively. Building emissions are proportionally small (cf. mid-latitudes), as there is neither need for space heating nor frequent use of air conditioning, and little heavy industry. The AHE spatial heterogeneity is large, with annual-average maxima of 124 W m⁻² at hectometre scale, but dropping rapidly to 10 W m⁻² at kilometre scale. City-wide projections of AHEs from 2020 to 2035 range between 24 and 61% increase.