1. Climate change and public health: a challenge to urban centres
Carlos Corvalan and Diarmid Campbell-Lendrum
World Health Organization, Geneva, Switzerland.
XI WORLD CONGRESS ON PUBLIC HEALTH VIII BRAZILIAN CONGRESS ON COLLECTIVE HEALTH Riocentro Convention Center Rio de Janeiro, August, 2006

2. URBANIZATION: Proportion of global population living in cities has increased dramatically in past Century : 15%. Now : 50%
Population growth and urbanization, 6 5
Rural 4 3 2
Urban 1
1900
2005

3. Challenges from climate change for developing country cities
Geographical location:
e.g. many are located on coasts, vulnerable to both sea level rise and storms;
Built environment:
e.g. many cities experience a significant urban heat island effect, exacerbating the impacts of heatwaves;
Co-exposures:
e.g. many cities have high levels of air pollution, which interact with high temperatures to increase mortality and morbidity
Weak infrastructure:
e.g. high population density and poor sanitation waste/disposal promotes transmission of important infections.

4. Does climate change have a large impact on health?
Burden of disease by region: Climate change and urban air pollution
Disability Adjusted Life Year per million. World Health report 2002.
Climate change Air pollution
Africa region
South-East Asia region
Eastern Mediterranean region
Latin America and Caribbean region
Western Pacific region
Developed countries
Cardio- pulmonary diseases
Respiratory infections
Trachea/ bronchus/ lung cancers
Diarrhoeal diseases
Malaria
Unintentional injuries
Protein-energy malnutrition

5. Health vulnerabilities
Heatwaves:
Urban heat island effect
Interaction with air pollution
Weak social networks
Lack of early warning systems and public health information
Urbanization brings range of health vulnerabilities to CV &CC:
Most obvious = heatwaves.
Most cities show a large heat island effect, registering 5-11°C warmer than surrounding rural areas (7). But the effects of land cover change on climate are not limited to small areas: in southeast China, land use change from urban sprawl has been estimated to account for ~0.05°C warming per decade since 1978 (8).

6. Heat Island effect

7. 12-day Heatwave, 3-14 Aug, 2003 Maximum Temperature, Aug 10
Excess Mortality:
France:
> 14,000
Italy:
~ 10,000
Spain &
Portugal:
~ 5,000
Etc.
Total =
~35,000

8. Health impacts: Heatwaves
Heatwave in France, Over 14,000 people died

9. Health vulnerabilities
2. Floods and storms:
Largest cities are on the coast
Degradation of natural protection
Poor quality housing in exposed areas
Inadequate disaster response plans
Caracas 1999.
Construction patterns in many developing cities have resulted in a combination of degradation of natural protection (deforestation, building on floodplains etc.), poor quality housing construction on exposed slopes, and extensive ground coverage of concrete without adequate drainage.

10. Health Impacts of Floods
Immediate deaths and injuries
Non specific increases in mortality
Infectious diseases – leptospirosis, hepatitis, diarrhoeal, respiratory, & vector-borne diseases
Exposure to toxic substances
Mental health effects
Increased demands on health systems
Philip Wijmans, LWF/ACT Mozambique, March 2000

11. Hurricane Katrina

12. Health vulnerabilities
3. Infectious disease:
Inadequate water and sanitation provision
High population density and high contact rates
High levels of imported infections
Inadequate disease warning, control and treatment

13. Urban infectious disease:
Dengue
Modelling studies suggest that climate change would increase the proportion of the global population exposed to dengue from about 35%, to 50-60%, by This on top of likely increased risks from unplanned development and mixing of pathogens.
Hales et al, Lancet 2002; 268:

14. Urban infectious Disease: Diarrhoea
Diarrhoea increases by 8% for each 1 degree centigrade increase in temperature.
(Reproduced with permission from Checkley et al., Lancet, 2000)

15. Health vulnerabilities
4. Air pollution: How big are potential health co-benefits of improved energy policies?
Outdoor Air pollution only:
700,000 deaths in 2020 (Davis et al, 1997)
64,000 deaths between 2000 to 2020, in Mexico City, Santiago, Sao Paulo and New York (Cifuentes et al, 2001)
Not yet considered:
Proportion of 1.2 million annual deaths from traffic accidents?
Proportion of 1.7 million annual deaths from IAP?
Proportion of 1.9 million annual deaths from physical inactivity?

16. Different routes are possible
Atlanta
Bangkok
Singapore
Houston
Zurich
Sao Paulo
Washington
Hong Kong
London
Alternative models are possible, that are likely to be healthier both in terms of the direct implications for health, but also in terms if environmental impacts.
A third of car trips in Europe cover under 3 kilometres and half less than 5 kilometres, distances that can be covered by bicycle in 15–20 minutes or by brisk walking in 30–50 minutes (WHO 2004). Some cities have even banned or discouraged cycling because there are too many cars on the road (Barter 2003)
Beijing
Kenworthy, 2003

17. Protecting health while reducing Emissions
Buildings
Indoor air pollution
Heat and cold
protection
Transport
Air pollution
Traffic injuries
Physical inactivity
Greenhouse Gas
Emissions
Industry
Occupational risks,
mining and transport
Energy supply
& conversion
Occupational risks;
Construction and transport
Agriculture
Nutrition,
Water /
vector-borne disease
Waste
Occupational,
chemical

18. Adaptation to climate change:
Conclusions
Adaptation to climate change:
Urbanization is occurring rapidly, changing nature of health vulnerabilities to climate variability and climate change
Vulnerabilities can be reduced both by general development and health provision, and (sometimes) by targeted climate information
Climate Change Mitigation:
Policies concerning urban energy sources and use (e.g. transport), have strong direct links to globally important health impacts.
Health considerations should be central in energy (=CC) decisions
City-level actions are critical to the future of health adaptation to Climate Change and also to CC mitigation
We know
1) That this is important for health
2) That it is becoming more important for health
3) There are many possible routes that especially developing economies could follow, and that these are important decisions directly from a health point of view
We don’t yet have a comprehensive general agreement on:
What the full range of implications are for health in the wide sense – e.g. community cohesion, mental well being. Depression expected to jump from 4th largest burden of disease in 1990 to 2nd in 2020.
A review of good practice in cutting emissions, especially for cities at different stages of development- those that are designing transport systems almost from scratch (e.g. model cities designed by McDonough), versus those where it is being modified after the event (e.g. Bogota).
Quantification of the effects of policy changes on health; e.g. just how much would the provision of better cycle lanes in London in the run up to the Olympics promote physical activity?
BL: we know this is important for health, but we don't yet know what best practical advice to give people

19. Thank you http://www.who.int/globalchange
Thank you