Download Climate Change and Human Health

Climate Change and Human Health:
an overview
Sari Kovats
17 October 2005
RSS Meeting
Centre on Global Change and Health,
Department of Public Health and Policy,
London School of Hygiene and Tropical
Medicine.
International environment
agenda
1972 Club of Rome Limits to Growth .
1972 UN World Conference on the Human Environment.
 1987. World Commission on Environment and Development “Our


Common Future”

WSSD. [World Summit on Sustainable Development] Rio 1992
– Framework Conventions on Climate Change, Biodiversity and others.
– Agenda 21


1997 Kyoto Protocol
WSSD - Johannesburg 2002 [Rio+10]
– UN Kofi Annan proposed five key areas for particular focus: WEHAB
[Water, Energy, Health, Agriculture, Biodiversity]
2005 Kyoto Protocol comes into force. US opts out.
 Millennium Development Goals

Shifting environmental burdens
Local
Global
Immediate
Delayed
Risks to
human health
Risks to life
support systems
Smith et al. 1999
Source: WHO, 2003: Climate change and human health: risks and responses.
Past changes in global mean temperature
Global mean temperature..
future projections
6.00
Change in Global Temperatures wrt 1961-90 (°C)
5.00
4.00
IS92A
A1FI
A2a
A2b
A2c
A2(Mean)
B1a
B2a
B2b
B2(mean)
3.00
2.00
1.00
0.00
-1.00
1961
1971
1981
1991
2001
2011
2021
2031
Year
Source: IPCC, 2001
2041
2051
2061
2071
2081
2091
1990
Reasons for concern
Temperature change (oC)
6
5
4
3
Observed
A1F1
A1B
A1T
A2
B1
Several models All SRES Envelope
B2
IS92A
2
1
0
-1
1900
2000
2100
I
I
II
III
IV
V
Risks to Unique and Threatened Systems
II Risks from Extreme Climate Events
III Distribution of Impacts
IV Aggregate Impacts
V Risks from Future Large-Scale Discontinuities
Changes in phenomenon
Confidence in
observed
changes
(latter half of
1900s)
Confidence in
projected
changes to
2100
Likely
Very likely
Very likely
Very likely
Likely
Very likely
Likely,
(N mid to high
latitudes)
Very likely
Increased summer continental drying and
associated risk of drought
Likely, in a few areas
Likely, over most midlatitude
continental
interiors.
Increase in tropical cyclone peak wind
intensities
Not observed in the
few analysis
available
Likely, over some
areas
Increase in tropical cyclone mean and
peak precipitation intensities
Insufficient data
Likely, over some
areas
Higher maximum temperatures
- more hot days
Higher minimum temperatures,
- fewer cold days and frost days
Increase of heat index over land areas
More intense precipitation events
IPCC WORKING GROUP I Third Assessment Report 2001
Climate change
may entail
change in
variance, as well
as a change in
mean
Mortality in Paris during 2003 heat wave
:
1999-2002 versus 2003
approx 27,720 deaths
2003 – Italy, 1/6 to 15/8
3134 (15%) in all
Italian capitals.
Deaths in same period in 2002
(Conti et al., 2005)
2003 – France
1/8 to 20/8
14802 (60%)
Average of deaths for same period in
years 2000 to 2002
(Insitut de Veille
Sanitaire, 2003)
2003 – Portugal
1/8 to 31/8
1854 (40 %)
Deaths in same period in 1997-2001
(Botelho et al., 2005)
2003 – Spain
1/8 to 31/8
3166 (8%)
Deaths in same period 1990-2002
(Navarro et al., 2004)
2003- Switzerland,
1/6 to 31/8 [3 months]
975 deaths
(6.9%)
Predicted values from Poisson
regression model.
(Grize et al., 2005)
2003 – Netherlands
01/06 – 23/08
1400 deaths
Number of degrees above 22,3 °C
multiplicated with the estimated
number of excess deaths per degree
(25-35 excess deaths
(Centraal Bureau voor de
Statistiek (CBS), 2003)
2003 - BadenWuertermburg, Germany
01/08 – 24/08
1410 deaths
Calculations based on mortality of past
five years
(Sozialministerium
Baden-Wuerttemberg,
2004)
2003 – Belgium
1297 deaths for
age group over
65
Average of deaths for same period in
years 1985 to 2002
(Sartor, 2004)
2003 – England and Wales
04/08-13/08
2091 (17%).
Average of deaths for same period in
years 1998 to 2002
(Johnson et al., 2005)
Impacts of climate change
Agriculture and food security
 Sea level rise, coastal flooding and coastal
areas.
 Biodiversity and ecosystems
 Water resources

Human health
 Infrastructure, industry and human
settlements
 Weather disasters (floods, storms).

How climate change affects health
Moderating
influences
HEALTH EFFECTS
Heat-related
illness, death
REGIONAL
WEATHER
CHANGES:
CLIMATE
CHANGE
- extreme
weather
- temperature
- precipitation
Flood, stormrelated health
effects
Air pollution
levels
Contamination
pathways
Transmission
dynamics
Air pollution effects
Water- and food
borne diseases
Vector-borne and
rodent-borne
disease
Adaptation
measures
three research tasks
Empirical studies
[epidemiology]
learn
?analogues
mechanisms
responses
past
detection
attribution
present
predictive
modelling
Future
2020s, 2050+
Complexity: different types of
evidence for health effects



Health impacts of individual extreme events
(heat waves, floods, storms, droughts);
Spatial studies, where climate is an
explanatory variable in the distribution of the
disease or the disease vector
Temporal studies,
– inter-annual climate variability,
– short term (daily, weekly) changes (weather)
– longer term (decadal) changes in the context of
detecting early effects of climate change.

Experimental laboratory and field studies of
vector, pathogen, or plant (allergenic) biology.
Assessment of causality…






measure and control confounders;
describe the geographical area from which the health
data are derived;
use appropriate observed meteorological data for
population of interest (the use of reanalysis data may
give spurious results for studies of local effects);
have plausible biological explanation for association
between weather parameters and disease outcome;
remove any trend and seasonal patterns when using
time-series data prior to assessing relationships;
report associations both with and without adjustments
for spatial or temporal autocorrelation.
Detection and attribution
What is the scientific evidence that global
climate change is affecting human health?
 Where and how should we be looking for
evidence?
 Considering the paucity of data, what do
we accept as evidence within this context?

Tick-borne Encephalitis, Sweden: 1990s vs 1980s:
winter warming trend
Early
1980s
Mid1990s
White dots indicate locations where ticks were reported. Black line indicates study region.
(Lindgren et al., 2000)
Evidence on biological effects of
observed climate change
effects on physiology: metabolic or
development rates of animals, and plant
processes;
 effects on distributions: response to shifts in
mean temperature and precipitation conditions
 Effect on phenology: timing of life-cycle
events, e.g. budding of flowers or egg laying;
 Adaptation: species with short generation
times and rapid population growth rates may
undergo some micro-evolution.

Hughes 2000
Evidence of northward shifts:
Europe
Bluetongue virus- disease and vector in Europe
– (Mellor and Hamblin, 2004; Purse et al., 2005)
 Leishmaniasis (which also affects humans) in
dog reservoir

– ? role of previous underreporting (Lindgren and Naucke,
2005)

Tick vectors– Sweden (Lindgren and Talleklint, 2000; Lindgren and
Gustafson, 2001)
– Denmark (Skarphedinsson et al., 2005)
– Canada (Barker and Lindsay, 2000)
How CC differs from other environmental
health risk assessments

Scenario based.
– Population not individual exposure
assessment

Future worlds:
– Population growth
– Development pathway
 disease baseline
 relationship between climate and impacts
(adaptive capacity)
Global Burden of Disease
Standard method developed by WHO.
 Based on best-available quantitative evidence
 Estimates by region, age, sex
 Combined metric – DALY

– Disability adjusted life year

Identifies global and regional health priorities…
Modelling impacts of climate change
Greenhouse gas
emissions
scenarios
2050
2100
Time
Defined by IPCC
2020s
2050s
Global climate
scenarios:
2080s
Generates series of maps of
predicted future distribution of
climate variables
30 year averages
Impact models
Estimates of populations at risk
• hunger
• water stress
• coastal flooding
• malaria
• dengue
2020s
2050s
2080s
1.2
1.1
1
.9
.8
Relative risk
Assumptions:
e.g. heat-related mortality
1.3
All-cause mortality

Adaptive capacity
0
10
20
Maximum temperature (lag 0)
– Climate change concept, reflects ability of a
population to cope with impacts of climate change

Acclimatization
– Threshold of mortality response moves

Changes in exposure response relationship
– E.g. due to changes in air conditioning access, etc.
– Evident for both heat and cold effects
– ?independent of aging population

Evidence base
– Published studies that show observed changes since
1900….Heat (Davies, Keatinge) and cold (Kunst, Keatinge,
Carson)
30
40
Urban area
Health
outcome
measure
Model
Climate
scenario
Non-climate
assumptions
Results
ref
UK
Heat- and
cold-related
mortality
and hospital
admissions.
Empiricalstatistical
model,
derived
from
observed
mortality.
UKCIP
scenarios
2020s,
2050s,
2080s
No population
growth. No
acclimatization
assumed.
Medium-high climate
change scenario would
result in an estimated
2800 heat deaths per
year in the UK in the
2050s (250%
increase). Greater
reductions in coldrelated mortality.
Keatinge et al.
(Department
of Health,
2002)
Lisbon,
Portugal
Heat-related
death
Empiricalstatistical
model,
derived
from
observed
summer
mortality.
2xCO2
emissions
RCMs:
PROMES
and
HadRM2
SRES population
scenarios.
Assumes some
acclimatization.
Increases in heat
related mortality, by
2020s, to range 5.815.1 deaths per
100,000, from baseline
5.4-6 deaths per
100,000
(Dessai, 2003)
Six cities in
Australia
[Adelaide,
Brisbane,
Hobart,
Melbourne,
Perth,
Sydney]
Two cities in
New Zealand
[Auckland,
Christchurch]
Heat- and
cold-related
mortality in
over 65s
Empiricalstatistical
model,
derived
from
observed
monthly
mortality.
High,
medium
and low
emissions.
CSIROMk2,
ECHAM4
Population
growth, and
population
ageing.
No
acclimatization.
Increases in heatrelated mortality in
over 65s, increases
large in temperature
cities. Less reductions
in cold related
mortality.
(McMichael et
al., 2003)
World
World Health Report 2002
Global Burden of Disease
World Health Organization
Africa
High child,
high
adult
High child,
very
high
adult
M
F
Both
M
F
M
F
(000)
(000)
(000)
(000)
(000)
(000)
(000)
Tobacco
3 893
1 014
4 907
43
7
84
26
Alcohol
1 638
166
1 804
53
15
125
30
163
41
204
5
1
1
0
Unsafe water, sanitation hygiene
895
835
1 730
129
103
207
169
Urban air pollution
411
388
799
11
11
5
5
Indoor smoke from solid fuels
658
961
1 619
93
80
118
101
Lead exposure
155
79
234
5
4
4
3
Climate change
76
78
154
9
9
18
18
Risk factors for injury
291
19
310
14
1
18
1
Carcinogens
118
28
146
1
0
1
1
Airborne particulates
217
26
243
3
0
3
0
Ergonomic stressors
0
0
0
0
0
0
0
Noise
0
0
0
0
0
0
0
Addictive substances
Illicit drugs
Environmental risks
Occupational risks
Applying the relative risk to baseline
incidence
Diarrhoea incidence in AfrD
Ann. Incidence/1000
1.4
No cc
UE (low)
1.3
UE (mid)
UE (high)
1.2
1.1
1
0.9
0.8
1990
2000
2010
2020
Year
2030
2040
Three eras of public health practice
Era
Risk
Source
Public health
response
Industrial revolution
1870-1930
Infectious disease
Cholera, diphtheria,
TB
Water, air,
crowding
Technical
solutions
Sewerage, domestic
hygiene, urban
design
Economic
development
1930-1970
Ways of living.
Lead, asbestos,
Acute toxicity, lung
waste
cancer, chemicals
Lifestyle change
Petrol standards,
monitoring and
reporting,
Sustainable
Development
1970-
Global stress
Melanoma, disease
spread, allergies,
toxicity
Governance
solutions
CFC controls, limit
energy use,
environmental
management.
Source: Brown et al. 2005, p 5.
UV radiation,
climate
change,
environmental
degradation
Conclusions
Estimates of near term impacts for health policy
decision makers
 Need scenarios of extremes
 Downscaling

– Interactions between cc and UHI [urban heat island]



Importance of population projections
Competing trends
Importance of metrics
– Deaths, YLL, dollars.

Modifiers and adaptive capacity
– Must be evidence based, but up to a point….