Posted on 15 March 2025 by Sue Bin Park

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Is waste heat from industrial activity the reason the planet is warming?

Waste heat’s contribution to global warming is a small fraction of that brought about by carbon dioxide.

Waste heat comes from the thermal energy released by human energy use, such as when power plants burn coal or combustion engines burn gasoline.

Dividing the total amount of waste heat by Earth’s surface area, Flanner found about 0.03 Watts per square meter of total warming was from waste heat, about 1%. Carbon dioxide’s greenhouse gas effect added 2.9 Watts per square meter.

Zhang and Caldeira published in 2015 that 1.71% of warming was from the direct heat energy released by fossil fuel combustion, the main source of waste heat.

Carbon dioxide, which makes it more difficult for heat to escape the atmosphere, is the primary driver of climate change. While reducing waste heat is beneficial for efficiency, addressing global warming requires lowering greenhouse gas emissions.

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Sources

Geophysical Research Letters Time scales and ratios of climate forcing due to thermal versus carbon dioxide emissions from fossil fuels

Atmospheric Environment Global anthropogenic heat flux database with high spatial resolution

Geophysical Research Letters Integrating anthropogenic heat flux with global climate models

NSF National Center for Atmospheric Research Anthropogenic Heat Flux

Scientific Data Global 1-km present and future hourly anthropogenic heat flux