To prepare for rising temperatures, scientists map urban ‘hot spots’

Heat islands can run 17 degrees F hotter than a city’s cooler areas. Studying them now may yield ideas for mitigating future warming.

This story appears in the August 2019 issue of National Geographic magazine.

Thermometer-wielding volunteer drivers are partnering with climate researchers to create maps of urban heat islands across the United States. On a hot day in Washington, D.C., for example, temperatures varied nearly 17 degrees F between the warmest spot and the coolest. To cope with the heat, many cities are planting trees and carving out open spaces. The National Oceanic and Atmospheric Administration, which funded the research, plans to expand it to help cities figure out ways to keep their cool in a warming world.

Leafy trees

in parks transpire water vapor and block sunlight.

Dense, dark

surfaces

like asphalt and concrete absorb and radiate heat.

85.4°

ROCK

CREEK

PARK

101.9°F

WASHINGTON, D.C.

101.9°F

100.2°F

94.5°F

2 mi

93.5°F

92.4°F

2 km

85.4°F

Temperature on

Aug. 28, 2018 3 p.m.

SHIELDED FROM SUNLIGHT

Shady parks and gardens “air-condition” wealthier neighborhoods west of Rock Creek Park. Built-up commercial hubs with paved-over areas, such as those in Georgetown, are warmer.

PAVEMENT AND POOR HEALTH

In eastern neighborhoods, industrial warehouses, rail yards, and paved expanses dot the landscape. People here can face high energy costs and heat-related illnesses.

Sources: VIVEK SHANDAs and OTHERS,

CLIMATE, 2019; NOAA

SHIELDED

FROM SUNLIGHT

Shady parks and gardens “air-condition” wealthier neighborhoods west of Rock Creek Park. Built-up commercial hubs with paved-over areas, such as those in Georgetown, are warmer.

PAVEMENT AND

POOR HEALTH

In eastern neighborhoods, industrial warehouses, rail yards, and paved expanses dot the landscape. People here can face high energy costs and heat-related illnesses.

85.4°

CHEVY

CHASE

ROCK

CREEK

PARK

BRIGHTWOOD

Dense, dark

surfaces

like asphalt and concrete absorb and radiate heat.

TENLEYTOWN

Old Soldiers’

Home Golf

Course

BROOKLAND

PALISADES

COLUMBIA

HEIGHTS

NATIONAL

ZOO

McMillan

Reservoir

101.9°F

Georgetown

Reservoir

U.S.

NATIONAL

ARBORETUM

GEORGETOWN

SHAW

WASHINGTON, D.C.

White

House

U.S.

Capitol

Temperature on

Aug. 28, 2018 3 p.m.

THE MALL

CAPITOL

HILL

101.9°F

Tidal

Basin

100.2°F

FORT

CIRCLE

PARK

ANACOSTIA

PARK

ANACOSTIA

94.5°F

1 mi

93.5°F

1 km

92.4°F

Bolling

Air Force

Base

Leafy trees

in parks transpire water vapor and block sunlight.

85.4°F

Sources: VIVEK SHANDAs and OTHERS,

CLIMATE, 2019; NOAA