1. Urban Heat Islands An urban heat island is a metropolitan area which is significantly warmer than its surrounding rural areas.

2. Bare earth and vegetation

3. Water

4. Albedo

5. Buildings and the Ground Store Heat

6. Sources of Heat

7. Cityscapes v landscapes

8. Energy in and out

10. London, 2000 British Museum Richmond Park

11. London, Summer 2000 Sunrise sunset

12. Chicago

13. 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

14. Excess mortality rates in early August 2003 indicate about 40,000 heat-related deaths Daily mortality in Baden-Württemberg

15. observations HadCM3 Medium-High 2003 2050s Temperature anomaly (wrt 1961-90) °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,”

16. 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.

17. Other Consequences The growing season can be up to 15 days longer in a city! Warmer in a city in winter Rainfall

18. How to reduce urban heat islands