Original title: Anthropogenic Heat in Urban Climate Systems: Forcing, Sensitivity, and Feedback
Dan Li, Alvin Christopher Galang Varquez, Ting Sun, Yuya Takane +3 · August 2026
Cities release a lot of extra warmth into the air. This heat comes from running buildings, driving vehicles, operating factories, and even human bodies. Scientists call this waste energy anthropogenic heat fluxThe rate at which human activities release heat into the environment.. The problem is that despite decades of research, this warmth is still one of the least understood parts of the urban energy balanceThe accounting of all energy entering and leaving a city, including sunlight, heat, and human releases.. It warms cities up, drives the urban heat island effect, and alters local weather patterns. It also links directly to greenhouse gas emissions and energy use. The researchers reviewed existing knowledge to explain how this process works. They built a framework showing how human heat acts as a trigger, how city temperatures respond, and how climate feedbacks change that response. Finally, they identified priorities for future research.
Imagine trying to keep a room comfortable on a hot day. You know the sun is adding heat, but you cannot see it, and the amount depends on how many people are inside, whether the machines are running, and how the walls absorb warmth. If you guess wrong, the room gets hotter than expected, and your next guess is based on a room that has already changed. In this paper, the heat from human activities in a city is the unseen heat source, and the room's changing temperature is the city's temperature responding to it. The challenge is that the heat source and the response affect each other, so a simple estimate never quite settles down.
City planners and climate modelers need to know how much heat buildings, traffic, and people add to the air. That heat strengthens the urban heat island and is tied to energy use, greenhouse gas emissions, and climate adaptation. A clearer physical understanding helps make city temperature forecasts and heat plans more reliable.
Because this is a review, it does not present new measurements or model results. The abstract gives no quantitative estimates of anthropogenic heat flux or its temperature impact. The framework's usefulness is not yet tested against specific cases.
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Anthropogenic Heat in Urban Climate Systems: Forcing, Sensitivity, and Feedback — Dan Li, Alvin Christopher Galang Varquez, Ting Sun et al.
Abstract licence: CC0
Explanation generated by Synthesis from the abstract — it is not the original paper. This is a preprint, so it hasn't necessarily been peer reviewed.