PORTLAND, Ore. -- A phenomenon scientists call "urban heat islands" can have serious health effects for hundreds of millions of people during the hottest months of the year, and Portland is among the 10 worst cities, according to Climate Central.
What is an urban heat island? Scientists explain that cities are almost always hotter than their surrounding rural areas, but global warming takes that heat and makes it worse. They warn that in the future, this combination of urbanization and climate change could raise city temperatures to levels which will threaten human health, strain energy resources, and compromise economic productivity.
The Climate Central study ranked Portland as No. 4 and Seattle as No. 10, among cities with the most intense summer urban heat islands over the past 10 years.
Researchers with Climate Central said more than 80 percent of Americans live in cities with rising temperatures caused by increasing heat-trapping greenhouse gas emissions.
The report warned that heat is already the No.1 weather-related killer in the U.S., and the hottest days, particularly days over 90°F, are associated with dangerous ozone pollution levels which can trigger asthma attacks, heart attacks, and other serious health impacts.
Here is the full list of the 10 worst urban heat islands, according to Climate Central:
- Las Vegas (7.3°F)
- Albuquerque (5.9°F
- Denver (4.9°F)
- Portland (4.8°F)
- Louisville (4.8°F)
- Washington, D.C. (4.7°F)
- Kansas City (4.6°F)
- Columbus (4.4°F)
- Minneapolis (4.3°F)
- Seattle (4.1°F)