Tony McMichael
Colin Butler
National Centre for Epidemiology and Population Health
The Australian National University
Canberra
• Global health indicators have been improving - with some localand temporary exceptions
• World population size has been growing rapidly• So have aggregate economic activity and consumption levels• Simultaneously, many large-scale environmental and ecological
indices have been declining• Can we explain this apparent paradox?• What is the relationship of population health to sustainable
development?• Anticipatory versus empirical approaches: Is “evidence and
information” (the WHO orthodoxy) adequate for Big Policy?
Mortality Trends, Sweden, 1750-2000
Val
ue
Year
1750 1800 1850 1900 1950 2000
0
0.1
0.2
0.3
0.4
0.5
Male 5q0Female 5q0
Val
ue
Year
1750 1800 1850 1900 1950 2000
0
0.2
0.4
0.6
0.8
1
Male 45q15Female 45q15Probability, at birth,
of dying by age 5 yrsProbability, at age 15,of dying by age 60 yrs
Based on: Murray C, WHO, 2002
Males Females
Developing Countries, 1990s
Age-standardised death rate by socialclass (I-V), adult males, England and
Wales, 1911-1991
0
200
400
600
800
1,000
1,200
1,400
1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
Dea
ths
per
100
,000
Based on ONS UK:Based on ONS UK: Health Inequalities Health InequalitiesDecennial SupplementDecennial Supplement
I
IIIII
V
IV
Year
0
0.2
0.4
0.6
0.8
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35
5q0Infant/child mortality
Adu
lt m
orta
lity
Based on: WHO, 2002
1% by 10%
0
20
40
60
80
100
1750 1800 1850 1900 1950 2000
Ind
ex o
f G
lob
al E
nvi
ron
men
tal
Ch
ang
e (%
)
Year Extension of earlieranalysis, of CD Butler
270
290
310
330
350
1966 1976 1986 1996
kgs
gra
in p
er c
apita
0
Time trend in global per-person production of cereal grain
2001
Three possible explanations:
• Modern societies, via technological, economic and politicalachievements, have become immune to environmental adversity.
• Adverse health effects are already occurring, but we cannot yetsee them.
• Lag period between environmental decline and health impacts.Lag reflects: (i) living off “capital”, (ii) buffering by culture.
Explanation 1 is untenable. Historically, the experience of manysocieties shows that, eventually, all are accountable within anecological sustainability calculus. A combination of explanations2 and 3 seems most plausible.
Human Population CarryingCapacity
• Non-human species: CC = f [natural capital]
• Humans: CC = f [NC, FC, BC, SC, HC]
– Inter-convertibility of types of capital
– Ability to expand HCC via culture/technology
– But: need to conserve the essential NC
• The environment sets limits on the size ofthe supportable local human population(given its particular level of “demands”).
• Societies find ways to extend that limit.
• Sustainable societies achieve a trade-offbetween supportable population size andsustainable environmental impact.
– Financial capital: international coffee price
– Social capital: resurgent tribal tensions
– Natural capital: shortage of arable land
�
Hunter-gatherer
Industrialising
Agrarian
Human CarryingCapacity
Population Demandon Environment
Globally “developed”
Will economic globalisation, and wealth creation, facilitate theHealth Transition – and help us achieve Sustainable Development?
Assumption: That the global “human carrying capacity” issufficiently elastic - to technology and greater wealth - to support,in future, a bigger and richer (higher consuming) population.
Probably erroneous!
Current modes of wealth creation are also eroding Earth’s life-supports, thus jeopardising the sustainability of current and futurehealth gains.
Tension between the Health Transitionand Sustainable Development
Consumptionpatterns
Technologies
Environmentalimpact
Wastes
Populationhealth status
Social capital
Knowledge
Recent Past Present Future
Population size, and distribution
Culture
Economic activityCarrying capacity:
critical thresholds
Healthgains
Healthlosses
?
• A change in human health/survival is responsive, notpredictive
• Further, this biological response is delayed by theinterposing of culture and technology – which expandsHCC, usually at the expense of natural capital.
• Deferral of ecological debt – e.g.:– Succession of ocean fisheries– Irrigation of drylands– Cyclone-proof housing
Trends in selected causes of death for womenaged 30-59 years in Russia 1965-1999
0
20
40
60
80
100
120
140
160
180
1965 1970 1975 1980 1985 1990 1995 2000
Year
SD
R p
er 1
0000
0
Accidents and violence
Ischaemic heart disease
Stomach cancer Breast cancer
Rheumatic heart disease
Shkolnikov & Leon
1950 1975 2000
Botswana
Uganda
SouthAfrica
35
45
55
65
75
Lifeexpectancy(yrs)
Year
• HCC has a prospective (“carrying”) dimension
• Can today’s population, with its current lifeexpectancy, and demands, be “carried”?– Global Years of Life Expectancy (GYLE) = Global
Population x Life Expectancy at birth
– i.e., current demand + committed demand on NC
• If so, can this demand be met without detriment tofuture generations?
0.1
10
1000
1750 1800 1850 1900 1950 2000
Population (billions)
GYLE (billions)
Global population and global years of lifeexpectancy (GYLE), 1750-2000
Year
Po
pu
lati
on
an
d G
YL
E (
bill
ion
s)(l
og
sca
le)
Po
pu
lati
on
an
d G
YL
E (
bill
ion
s)(l
og
sca
le)
Population (billions)
GYLE(billions)
Global population, global years of life expectancy(GYLE), and Index of Global Env Change (IGEC):
1750-2000
0.1
10
1000
1750 1800 1850 1900 1950 2000
IGEC (%)
Year
100
1
• Reduced rate of increase in life expectancy– But, alternative explanations
• Increased infant mortality (classical indicator)
• Resurgence of infectious diseases
• Reduced fertility (state- or family-initiated)
• Increased tension and conflict, relating toenvironmental assets (space, resources, food)
70
74
78
82
1964 1969 1974 1979 1984 1989 1994 1999
Gin
i co
effi
cien
t (%
)
Global income distribution (US$), 1964-1999
Butler CD, 2001
Inequality
Great wealth
Medium wealth
Poverty
NOW FUTURE
Environmental brinkmanshipbetween countries
(Resource extraction, trade patterns, wastes)
Arrested(?reversed)healthgains
Affluent consumption
Gains in lifeexpectancy
Gains in lifeexpectancy
Environmentaldamage
Poor health Health losses
Over-use oflocal naturalresources
Band of historical climatic variability
20
15
1900 21002000
14
16
17
18
13
19Average GlobalTemperature (OC)
Year205019501860
Low
High
Central estimate = 3.0 oC
IPCC (2001) estimatesa 1.4-5.8 oC increase
This presents a rate-of-change problem for manynatural systems/processes
0
50
100
150
200
250
300
350
400
450
500
550
600
650
700
1 1.25 1.5 1.75 2 2.25 2.5 2.75 3 3.25Temperature Increase
Ad
dit
ion
al m
illi
ons
of
peo
ple
at
ris
k o
f h
un
ge
r, m
ala
ria
an
d f
loo
d
0
500
1000
1500
2000
2500
3000
3500
1 1.25 1.5 1.75 2 2.25 2.5 2.75 3 3.25
Ad
dit
ion
al m
illi
ons
of
peo
ple
at
ris
k o
f in
cre
as
ed w
ate
r s
ho
rta
ge
Sta
bili
satio
n @
750
pp
mv
Un
miti
ga
ted
Sta
bili
sa
tion
@ 5
50
pp
mv
Risk of flooding
Risk of hunger
Risk of malaria
Risk of water shortage
Legend
Malaria
Water shortage
Hunger
Flooding
Temperature increase1 oC 2 oC 3 oC
Additional millions of people at risk of increased water shortage
Additionalmillions of people at risk of hunger, malariaand flood
150
250
Preliminary Estimates of Risk Functions for 4 Major Health-Related Consequences of Climate Change (DETR, UK, 20010 )
Estimates of Additional, Global, Numbers of People at Risk of 4Major Health-related Impacts of Climate Change by circa 2050-80
Based on a setof studiescommissionedby UK Govt.
Gains in health and longevity over the past century have followedurbanisation, social modernisation, industrialisation and increasingmaterial wealth, plus advances in public health and health care.
However, those health gains have depended, to an uncertain extent,on the depletion and degradation of the world’s naturalenvironment.
Theory, personal experience, and an increasing body of empiricaldata* suggest the existence of critical thresholds beyond which liedangers to society and risks to population health.
* Scheffer et al., 2001; Rauch, 2002
• Cause-effect lag times• Multiplicity of influences on population health• Uncertain determinants of the environment’s human carrying
capacity
Recent mortality/health trends, globally andregionally, actually cannot tell us if our socio-economic development path is “sustainable”.
Health outcomes are responsive, not predictive.
Further difficulties are:
We must therefore use an anticipatory approach.