Climate • Now
Heatwave warning sign at sunset
Warning sign during a heatwave event

Heatwaves

When the Air Becomes Dangerous

Heatwaves are prolonged periods of unusually hot weather. They are becoming more frequent, longer, and more intense, turning everyday life into a health risk and straining power and water systems.

Why Common

Every region experiences heat; climate change shifts the odds and raises the ceiling.

Who Is at Risk

Elderly people, outdoor workers, children, and those without access to cooling.

Why It Matters

Heat is the deadliest weather hazard in many countries and amplifies other risks.

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Causes

Climate Warming

More greenhouse gases mean higher baseline temperatures and more extremes.

Atmospheric Patterns

Blocking highs trap heat and suppress clouds and wind.

Urban Effects

Concrete and asphalt store heat; nights stay hot.

Compounding Factors

Drought and dry soils reduce evaporative cooling and intensify heat.

Impacts

Health

Heat exhaustion and stroke; dehydration; medication interactions; sleep loss.

Power & Water

Peak demand surges; thermal plants and grids operate less efficiently; reservoirs drop.

Work & Learning

Outdoor labor and classrooms become unsafe without cooling and shade.

Air Quality

Heat accelerates ozone formation; wildfire smoke events often co-occur.

Solutions

Early Warning

Named heat events, alerts, and neighborhood check-ins.

Cooling Access

Cooling centers, night shelters, hydration points, utility shut-off protections.

Cooler Built Environment

Shade trees, cool roofs, reflective or permeable pavements, shaded bus stops.

Standards & Plans

Heat action plans, building codes for ventilation and insulation, urban canopy targets.

Take Action

Personal

Hydrate; avoid midday exertion; check on neighbors; know heat illness signs.

Home & Campus

Install fans or heat pumps; plant shade trees; add exterior blinds; map hot spots.

Community

Support cooling centers, tree-canopy programs, and worker heat protections.

Pair actions with a teach-in: collect stories and photos from recent heatwaves and share your plan.