1. Weather, climate and health
Simon Lloyd
London School of Hygiene
and Tropical Medicine

2. Health outcomes influenced by climate: likely impacts of climate change
Figure 8.3: Ch 8 Human Health, IPCC 4AR

3. Health outcomes influenced by climate: likely impacts of climate change
Impact on existing burden of disease
Various exposures of interest
At times, complex links
Figure 8.3: Ch 8 Human Health, IPPC 4AR

4. Health outcomes influenced by climate: likely impacts of climate change
Long term changes in means
Daily or weekly changes
Interannual variability
Extreme weather events
Impact on existing burden of disease
Various exposures of interest
At times, complex links
Figure 8.3: Ch 8 Human Health, IPPC 4AR

5. Health outcomes influenced by climate: likely impacts of climate change
Impact on existing burden of disease
Various exposures of interest
At times, complex links
Figure 8.3: Ch 8 Human Health, IPPC 4AR

6. Exposure – outcome relationships
Epidemiology at individual level
Exposure
Outcome
Cardiovascular disease
Smoking

7. Exposure – outcome relationships
Epidemiology at individual level
Exposure
Outcome
Cardiovascular disease
Smoking
Weather/climate and health:
Exposure at population level
Pathway (often) indirect and complex
Impact moderated by vulnerability

8. Climate change and health: Risks and Responses, WHO 2003.

9. Climate change and health: Risks and Responses, WHO 2003.

10. Climate change and health: Risks and Responses, WHO 2003.

11. Climate change and health: Risks and Responses, WHO 2003.

12. Types of evidence for health effects
Spatial studies
Climate as an explanatory variable in the distribution of the disease or the disease vector
Temporal studies
short term (daily, weekly) changes
inter-annual climate variability
longer term (decadal) changes in the context of detecting early effects of climate change.
Health impacts of individual extreme events
heat waves, floods, storms, droughts

13. Diarrhoea and average weather

14. Diarrhoea and average weather
rates

15. Diarrhoea and average weather
Temperature
Diarrhoea
rates
Mechanism: pathogen survival

16. Diarrhoea and average weather
Temperature
Diarrhoea
rates
High rainfall
Mechanism: water supply contamination (water quality)

17. Diarrhoea and average weather
Temperature
Diarrhoea
rates
High rainfall
Low rainfall
Mechanism: use of unprotected water sources; reduced hygiene
behaviour (water quantity)

18. Diarrhoea and average weather
Temperature
Water and
sanitation
Diarrhoea
rates
High rainfall
Malnutrition
Low rainfall
etc.
Climate type
Socioeconomic conditions

19. Data
Outcome
Exposure
Co-variates

20. Data Outcome Exposure Co-variates Diarrhoea morbidity
Children under 5 years
Low and middle income countries
36 study sites

21. Data Outcome Exposure Co-variates Av. temperature over study period
Av. rainfall over study period
CRU TS 2.1 dataset
Underlying climate
Köppen climate classification

22. Data Outcome Exposure Co-variates Socioeconomic conditions
Water and sanitation
Setting: urban, rural, slum

23. Study sites
Lloyd, Kovats & Armstrong. Clim Res 2007; 34:119-27

24. Diarrhoea cases vs average weather
Average monthly rainfall and log diarrhoea incidence in children aged months, showing country
Average temperature and log diarrhoea incidence in children aged 1 year, showing climate classification.
Lloyd, Kovats & Armstrong. Clim Res 2007; 34:119-27

25. Regression results Variable Model 1 Model 2 Model 3 Model 4 GDP
1.00 ( )
Precipitation
0.97 ( )
0.96 ( )
Temperature
1.02 ( )
1.03 ( )
Setting: rural 1
urban
0.73 ( )
slum
1.01 ( )
mixed
1.63 ( )
All models are adjusted for age group. Coefficients indicate the change in diarrhoea rate (episodes per child-year) for each: 10USD (in 2000 USDs) increase in GDP/capita; 10mm/month increase in average monthly rainfall; and, 1C increase in average temperature
Lloyd, Kovats & Armstrong. Clim Res 2007; 34:119-27

26. for each 10mm/month rainfall ↑
Regression results
Variable
Model 1
Model 2
Model 3
Model 4
GDP
1.00 ( )
Precipitation
0.97 ( )
0.96 ( )
Temperature
1.02 ( )
1.03 ( )
Setting: rural 1
urban
0.73 ( )
slum
1.01 ( )
mixed
1.63 ( )
Diarrhoea ↓ 4% (1 – 7%) for
for each 10mm/month rainfall ↑
All models are adjusted for age group. Coefficients indicate the change in diarrhoea rate (episodes per child-year) for each: 10USD (in 2000 USDs) increase in GDP/capita; 10mm/month increase in average monthly rainfall; and, 1C increase in average temperature
Lloyd, Kovats & Armstrong. Clim Res 2007; 34:119-27

27. Extreme events: coastal flooding
Spatial scale
WHO GBD regions

29. Extreme events: coastal flooding
Spatial scale
WHO GBD regions
Event and outcome data
International Emergency Disaster Database,
University of Louvain, Belgium.
EM-DAT

31. Initial estimates of impacts of extratropical & tropical cyclones, 1980 - 2007 [EMDAT, 2008]
Region
Events
Killed
Killed/event
Affected
Affected/event
AP_HI 83
2715 33
26 276
As_C 2
2800
1400
As_E
161
9736 60
As_S
105
1763
As_SE
247
33 461
135 Au 28 63
18 925
676 Ca
185
4478 24
82 703
Eu_C 6 13
8000
1333
Eu_E 21 71 3
15 682
Eu_W 36
236 7
96 533
LA_A 1
518
LA_C
109
23 799
218
LA_S -
LA_T 4
NA_HI 59
2447 41
NA_ME
127
30 008 Oc 94
688
17 276
SSA_C 17
SSA_E 62
2472 40
SSA_S
125 31
SSA_W 8
9322
2331

32. Initial estimates of impacts of extratropical & tropical cyclones, 1980 - 2007 [EMDAT, 2008]
Region
Events
Killed
Killed/event
Affected
Affected/event
AP_HI 83
2715 33
26 276
As_C 2
2800
1400
As_E
161
9736 60
As_S
105
1763
As_SE
247
33 461
135 Au 28 63
18 925
676 Ca
185
4478 24
82 703
Eu_C 6 13
8000
1333
Eu_E 21 71 3
15 682
Eu_W 36
236 7
96 533
LA_A 1
518
LA_C
109
23 799
218
LA_S -
LA_T 4
NA_HI 59
2447 41
NA_ME
127
30 008 Oc 94
688
17 276
SSA_C 17
SSA_E 62
2472 40
SSA_S
125 31
SSA_W 8
9322
2331

33. Initial estimates of impacts of extratropical & tropical cyclones, 1980 - 2007 [EMDAT]
Region
Events
Killed
Killed/event
Affected
Affected/event
AP_HI 83
2715 33
26 276
As_C 2
2800
1400
As_E
161
9736 60
As_S
105
1763
As_SE
247
33 461
135 Au 28 63
18 925
676 Ca
185
4478 24
82 703
Eu_C 6 13
8000
1333
Eu_E 21 71 3
15 682
Eu_W 36
236 7
96 533
LA_A 1
518
LA_C
109
23 799
218
LA_S -
LA_T 4
NA_HI 59
2447 41
NA_ME
127
30 008 Oc 94
688
17 276
SSA_C 17
SSA_E 62
2472 40
SSA_S
125 31
SSA_W 8
9322
2331
in a single
event in 1991

34. Interannual variability: ENSO
Human impact of natural disasters increases during El Niño
ENSO associated with infectious diseases in some areas, esp cholera risk and malaria epidemics
ENSO and seasonal climate forecasts may have public health use

35. Interannual variability: ENSO
Human impact of natural disasters increases during El Niño
ENSO associated with infectious diseases in some areas, esp cholera risk and malaria epidemics
ENSO and seasonal climate forecasts may have public health use
Global disaster burden associated with El Niño over
a 30 year period ( )
Exposure: consensus El Niño years
Outcome: affected by a natural disaster

36. World population affected by natural disasters
Rate per 1000 people,
El Niño years
Possible El Niño years
Non-El Niño years
Bouma, Kovats et al. Lancet 1997; 350:1435-8

37. World population affected by natural disasters
Rate per 1000 people,
Strongest association between El Niño and drought (including food shortage and famine):
sub-Saharan Africa, South America, and South and West Asia
Extreme rainfall and tropical cyclones: mixed effects by region
Bouma, Kovats et al. Lancet 1997; 350:1435-8

38. El Niño: a natural disaster cycle?
Bouma, Kovats et al. Lancet 1997; 350:1435-8

39. El Niño: a natural disaster cycle?
150
million
people
Bouma, Kovats et al. Lancet 1997; 350:1435-8

40. Climate and respiratory health in children

41. Climate and respiratory health in children
Previous studies
↓ temperature range
↓ relative humidity range
Asthma ↑ with:
↑ temperature in coldest month
↑ mean annual temperature

42. Data needs and queries
How well does data represent climate at particular study sites?
Are there areas that are not well represented?
Can data be used to quantify elements of events?
E.g. rainfall in floods; extent, intensity & duration of drought.
How well are ENSO events and their associated impacts on climate events represented?