heat·shed | /ˈhētˌshed/ | noun
1. The spatial and policy area across which extreme heat must be understood and governed as a shared condition — crossing city, regional, and national boundaries, as a watershed does for water. A heatshed does not stop at jurisdictional boundaries, and neither do the solutions required to address it.
2. A critical turning point at which extreme heat must be rapidly addressed to protect health and livelihoods worldwide. We are living through a heatshed moment.
— After watershed, which holds both senses: the land where all water drains, and the critical moment things change.
Extreme heat is the deadliest weather hazard in the United States, and the least prepared for. It kills more people than hurricanes, floods, and tornadoes, and yet cities and nations devote a fraction of the attention and resources to it that they give to those hazards.
One reason the world is unprepared for extreme heat is that it is a largely invisible hazard. Its impacts are less visually dramatic than hazards like wildfires or floods. These hazards also have hazard zones we can plan for: floods have floodplains and wildfires have wildland urban interface areas.
Another reason is that regional planning decisions that increase the urban heat island span jurisdictional boundaries. Similarly, when heatwaves occur, their impacts often span city, region, state, and even national borders, often exceeding our capacity to respond.
Finally, until recently, there were no dedicated heat plans, policies, or officials responsible for addressing it. The nascent efforts to address heat risk have historically been siloed off in professions like urban planning, public health, and emergency management. Compare this to other hazards, for which there are entire dedicated professions and government structures for protecting communities.
That is what a “heatshed” names. It’s the physical and policy scale at which heat actually operates, and therefore the scale at which it has to be planned for and governed.
Our cities were built for a climate that no longer exists. Planning cities for the climate we actually have today, and the climate that is coming in the near future, means addressing extreme heat the way we already address water: as a shared regional condition that demands coordinated governance across levels.
Where the term “heatshed” comes from
I introduced the concept of the “heatshed moment” first in my TEDxUofA talk, A “heatshed” moment for communities in crisis. I further made the case for the term in my commentary with Sara Meerow, “Our ‘heatshed’ moment is now” in the Journal of Urban Affairs, which builds on our earlier work defining heat resilience and heat governance.
Cite this
Keith, L., & Meerow, S. (2026). Our “heatshed” moment is now. Journal of Urban Affairs. https://doi.org/10.1080/07352166.2025.2526490