urban heat islands an urban heat island is a metropolitan area which is significantly warmer than...
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Urban Heat Islands
An urban heat island is a metropolitan area which is
significantly warmer than its surrounding rural areas.
The urban heat island is biggest…
• At night (before sunrise)
• In the summer
• When there is no wind
• When the sky is clear
• When the weather doesn’t change through the night
Excess mortality rates in early August 2003 indicate about 40,000 heat-related deaths
Daily mortality in Baden-Württemberg
observationsHadCM3 Medium-High
2003
2050s
Tem
per
atu
re a
no
mal
y (w
rt 1
961-
90)
°C
European 2003 summer temperatures
“Right now, we average about 14 days each summer above 90
degrees in New York. In a couple of decades, we could be experiencing 30
days or more,”
What’s that got to do with the UHI?
• London – 600 heat related deaths in August 2003
• Up to 9 °C warmer than surrounding rural areas• Mortality increases with temperature when
temperatures are over 22°C• Mortality particularly linked to warm night time
temperatures• Mortality linked to age, sex, deprivation etc.• Challenge now to design buildings and urban
areas for the future – which will see more people living in cities, and will be warmer.
Other Consequences
• The growing season can be up to 15 days longer in a city!
• Warmer in a city in winter
• Rainfall