This blog post and the “Deep Dive” podcast, created by NotebookLM, are based on “Energy‐Consumption‐Induced Anthropogenic Heat Release Intensifies Heatwaves and Wildfire Threats in North America: A CESM2‐Based Projection for the Late 21st Century” by Wang et al. (2025).
When we talk about climate change, the conversation almost invariably turns to greenhouse gases. Carbon dioxide, methane, and other atmospheric pollutants are rightfully seen as the primary drivers of global warming, trapping heat that would otherwise escape into space. This “greenhouse effect” is a critical piece of the climate puzzle, but it’s not the only way human activity is heating the planet.
There is another, more direct human impact that often goes overlooked: Anthropogenic Heat Release (AHR). This is the scientific term for the massive amount of waste heat generated from all our energy consumption. It is the heat shimmering above asphalt on a summer day, the warm air vented from an office air conditioner, the collective thermal footprint of a civilization running on high.
A new scientific study, using a state-of-the-art climate model, has projected the future impacts of this waste heat on North America by the end of the 21st century. Modeling a high-emissions, fossil-fueled development future (the SSP5-8.5 scenario), the findings are startling. They reveal that AHR doesn’t just contribute to warming in dense cities; it actively reshapes weather patterns, intensifies heatwaves, and elevates wildfire risk across the continent. Here are the five key takeaways from the research.
It’s Like Turning Up the Thermostat for an Entire Continent
Beyond the warming caused by greenhouse gases, the direct heat released from human activities will significantly raise North America’s baseline temperature. The study projects that by the late 21st century (2081-2100), AHR alone will contribute an average warming of 0.60°C to summer surface temperatures across the continent.
This increase is broken down into a 0.61°C rise in daily maximum temperatures and a 0.59°C rise in daily minimum temperatures. To put that in perspective, this is a direct heating effect that will be layered on top of the already-accelerating warming from greenhouse gas emissions. It’s a separate and compounding factor, directly adding thermal energy into the bottom of the atmosphere.
Dangerous Day-and-Night “Compound Heatwaves” Will Become More Common
One of the most dangerous forms of extreme heat is the “compound day-night heatwave.” This is a relentless period where extreme daytime temperatures are followed by unusually warm nights, offering no period of relief or recovery for human bodies, infrastructure, or ecosystems.
The study projects that AHR will increase the frequency of these dangerous compound heatwaves by an average of 0.2 days every summer across North America. While this represents a clear trend in the model, the study notes this specific continental average did not reach the threshold for statistical significance, though increases in certain regions like the central United States were more pronounced. This is so impactful because the lack of nighttime cooling is a major threat to human health, dramatically increasing the risk of heat-related illness and mortality. By constantly releasing heat, our energy consumption actively suppresses the natural cooling process that should occur after sunset, making heatwaves more hazardous.
It Literally Burns Off Protective Cloud Cover
Perhaps one of the most surprising findings is how AHR amplifies its own warming effect by changing the atmosphere. The study reveals that the heat released from the surface reduces “lower tropospheric stability.”
In simple terms, this means the heat disrupts the stable layers of air near the ground. This disruption leads to a significant reduction in low cloud cover over large parts of North America. With fewer low-level clouds to reflect sunlight back into space, more solar radiation reaches the surface, further increasing temperatures. In addition to this, AHR also increases the amount of heat radiated back down toward the ground from the atmosphere (downward longwave radiation), with regional average increases exceeding 2 W m−2. This adds to the warming from both above and below.
It Intensifies High-Pressure Systems, Creating Hotter and Drier Conditions
The uneven heating from AHR—concentrated in urban and industrial centers—is powerful enough to alter large-scale atmospheric circulation. The model shows that AHR is projected to intensify anticyclonic (high-pressure) circulation over the western part of the continent.
These high-pressure systems, often called “heat domes,” are characterized by sinking air. This sinking motion compresses and warms the air, leading to hotter and drier weather while suppressing cloud formation and precipitation. The study quantifies this drying effect, projecting an average summer precipitation reduction of 0.12 mm/day in the region between 45°N and 60°N latitude. Conversely, the model shows that enhanced warm, humid airflow from the Gulf of Mexico northward boosts precipitation in the southeastern United States, demonstrating how AHR actively reshapes weather patterns across the continent.
It Directly Increases Wildfire Risk by Drying Out the Landscape
The hotter and drier conditions created by AHR have a direct and measurable impact on wildfire risk. To assess this, scientists use a metric called Vapor Pressure Deficit (VPD), which is a key indicator of how dry the air is and the level of moisture stress on plants. High VPD means the atmosphere is effectively sucking moisture out of soil and vegetation, turning it into tinder.
The study found that AHR will substantially increase the summer VPD across most of North America. This finding is critical because, as the authors note by citing previous research, every 1 hPa increase in VPD can increase the number of high-intensity fires by 4.4% to 5.1%. By directly drying out the landscape, our waste heat is priming the continent for more frequent and intense wildfires.
Acknowledging Our “Thermal Blanket”
While greenhouse gases remain the dominant force in long-term global warming, this research makes it clear that Anthropogenic Heat Release is a significant and direct human forcing on the climate that deserves far more attention. The study’s authors use a powerful analogy to distinguish the effect of AHR from the greenhouse effect:
In contrast to the greenhouse effect, where greenhouse gases reduce the outgoing longwave radiation from the Earth–atmosphere system and cause warming, the heating effect of AHR is similar to placing a thermal blanket on the surface, with this impact unevenly distributed and mainly concentrated in urban areas.
This “thermal blanket” is not a passive consequence of our emissions; it is an active, energetic force reshaping our climate in real time. The research proves that our direct heat output is now a continental-scale weather maker, intensifying our most dangerous extremes from above and below.
As our energy consumption grows, how can our cities and policies evolve to mitigate not just what we emit, but the direct heat we release?
The infographic was generated by Notebook LM.
Wang, R., Wu, X., Chen, B., Lin, G., Wu, C., Luo, T., et al. (2025). Energy-consumption-induced Anthropogenic heat release intensifies heatwaves and wildfire threats in North America: A CESM2-based projection for the late 21st century. Journal of Geophysical Research: Atmospheres, 130, e2025JD044290. https://doi.org/10.1029/2025JD044290
Ocean to Climate 
Hello Sang ki !!!!
How the heck are you? And did that atmospheric river that hit Washington state cause any problems in Hawaii? Every day we are seeing weather extremes on the TV, but who’s keeping track of the frequency and intensity of those extreme weather events? If the data could be shown graphically on TV news it might help to inform the public and cause more people to take measures, like driving an EV. EV prices have come down and their driving economy is much better than their gas car equivalents. Fortunately, extreme weather is rare here in south Florida, mainly because we are surrounded by ocean. Of course there is the problem of a hurricane hitting us once every few decades.
Nice to hear from you! David
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