Climate Change & Health: A Housing Case Study He Kainga Oranga University of Otago, Wellington
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Climate Change &
Health:
A Housing Case Study
He Kainga Oranga
University of Otago, Wellington
Professor Philippa Howden-Chapman, Dr Simon
Hales, Dr Nick Wilson, Helen Viggers
Why Housing? • We spend about 90% of our time indoors – the very old and very young may spend almost 100% of their time indoors • Housing (in some form) is a human universal => small changes at an individual level can have a large total effect • Housing is intended to protect us from the environment
NZ Housing Context • NZ houses are cold and damp, with inadequate, often inefficient heating • Average winter temperature is 16oC (WHO recommends 18oC – 21oC) • 1,000x rule • 1600 excess winter deaths from respiratory and circulatory problems, compared to 900 deaths attributable annually to traffic pollution
Modifying Health
Healtheffects
Effects
influences
Temperature-related
illness and death
Extreme weather-
Extreme weather-
related (floods, storms,
related health effects
etc.) health effects
Human
Air pollution-related
exposures health effects
Existing models
Regional of health impacts
weather Microbial changes:
Contamination
Water and
Water and food-borne
food-borne
do not account
changesfor social or pathways diseases
Climate Contamination paths diseases
technological changes
Change
•Heat waves Transmission dynamics
Transmission
(adaptation) dynamics
Vector-borne
Vector borne and
and
•Extreme weather rodent
rodent- borne
borne diseases
diseases
•Temperature
•Precipitation
Changes in agro- Effects of food and
ecosystems, hydrology water shortages
Socioeconomic and Mental, nutritional,
demographic disruption infectious-disease and
other effects
Adaptation • Adaptation is the adjustment in natural or human systems in response to actual or expected climate changes and their effects • For social systems, adaptive capacity, resilience and vulnerability all matter • Projections come from past observation, observed interventions and modelling • Precautionary action essential & equitable
Outline
• Potential health effects – “2°C” scenario
• Local effects of heat, air pollution
• Altered infectious disease distribution (IPCC)
• Potential health effects – 4°C scenario
• Increase in above effects
• Likely major impact of global (incl. Pacific) social
disruption
• Adaptation measures (both scenarios)
• Housing, infrastructure (e.g. energy, water)
• Adaptation measures (high carbon scenario)
• “Lifeboat NZ”
Health effects of increasing
temperatures
• Warmer temperatures and increased rainfall
variability are likely to increase the intensity
and frequency of food-borne and water-borne
diseases.
• Higher than average temperatures lead to
~30% of reported European cases of
salmonellosis. In UK, monthly incidence of
food poisoning most strongly associated with
the temperatures occurring in the previous two
to five weeks.
Rise of respiratory diseases • Rise of tuberculosis globally and nationally • Crowding from population movement increases transmission of TB Baker M, Das D, Venugopal K, Howden-Chapman P. Tuberculosis associated with household crowding in a developed country. Journal of Epidemiology Community Health 2008;000:1–8:doi:10.1136/jech.2007.063610.
Health effects of increasing
temperatures
• Deaths in forest fires
• Impacts on aero-allergens and photochemical
smog in cities uncertain. Increase in bushfires
and smoke would increase hospital admissions
for cardio-respiratory conditions.
Drowning • Number of people at risk from flooding by coastal storm surges projected to increase • Currently 75 million people at risk • Projected 200 million in mid-range climate scenarios (40cm rise in sea level by 2080s)
Extreme climate events
Extreme Climate Events
• Physical destruction
• Immediate loss of life
• Major life event / stressor
• Ongoing effects if become a displaced
personNew Orleans
Taranaki
NiueMalibu
AustraliaBurundi
Britain,
KaeoExtreme climate event
Example Hurricane Katrina
• Structural factors affected poor black people
most
• Levees poorly maintained
• Residentially segregated to low lying areas
• Little public transport
• Corruption, no functional emergency plan
• Poor policy implementationWater quality • Increasing irregularity of supply • Social gradient in water quality in New Zealand • Water metering and charging could further increase inequalities and infectious diseases • Households need right to minimum amount of water at no charge -- important for cleanliness and contagion control
Infectious disease • Warmer temperatures and increased rainfall variability are likely to increase food-borne and water-borne diseases. • Infectious agents (protozoa, bacteria and viruses) and vector organisms (mosquitoes, ticks and sand-flies) no thermostatic mechanisms, so reproduction and survival rates are strongly affected by fluctuations in temperature.
Rise of infectious diseases • Parts of the North Island likely to become suitable for breeding of the mosquitoes that are major dengue vector • Much of NZ becomes receptive to other less- efficient vector species • The risk of dengue in NZ likely to remain below the threshold for local transmission beyond 2050, under both scenarios.
Example – Dengue Fever • No vaccine, no cure • Lasts 7-10 days “bonebreak fever” • Transmitted by Aedes aegypti, (a domestic, day-biting mosquito). Typically people might be bitten indoors in early morning or evening.
Model of baseline transmission
(1961-1990 climate)Model of future transmission
(2080s climate)Heat-related diseases • In Auckland and Christchurch, a small number of heat-related deaths occur annually in people aged over 65 and will increase (McMichael et al., 2003). • Current 1600 excess winter deaths likely to decline • N.B. European heat-waves in 2003 killed 70,000 people… epidemiological models did not predict this scale of mortality
European Heat-wave, 2003
• Number of deaths in July and August, France, 1946 - 2004
from Toulemon and Barbieri, 2005Deaths per day, France, August 2003
Observed and modelled summer temperatures
from Stott et al, 2004Vulnerability • People living in remote communities are likely to be at increased risk due to their particular living conditions and poor access to services. • Relationship between drought, suicide and severe mental health impacts in rural communities
Not all have equal opportunity Vulnerable populations have • Low income and little wealth • Less educated • The very young and old • Sole parents with children • Those with chronic illnesses and disabilities • Those living in socio-economically disadvantaged, residentially segregated areas • Those who suffer racial discrimination
Balance of Health Impacts?
• Most, not all, health impacts are expected to be
adverse
• Gains include: mosquito decline in some regions; lower
winter death-rates in some countries; increased food yields
in some regions
• Rapid change of mean temp by several degrees, over
decades, will cause widespread ecological stress and
physical changes
• Critical factor in recent Aust drought = extra 1 oC
• Weather extremes and disasters pose an additional
health hazardMayan Building, Empire 1800BC – 1000 AD
How Can Housing Help?
Traditional housing has been designed for traditional
weather patterns / pests.
(e.g. mud in Nigeria, wood in Australia/ NZ)
• Mitigation – lowering carbon emissions
• Adaption – adapting to the changed environment
• Ignore – (& hope the problem will go away)
Ideas????Overall,
e.g. heat wave
Individual Urban National
Short term Behaviour in Heat plan Early warning
measures summer and systems
during
heatwave
Medium term A/C Modify existing Economic policy
measures buildings (energy,
transport,
buildings)
Long term Passive cooling Design of Energy
measures buildings and efficiency
cities (including standards.
transport?) -
reduce heat
islandsAdvantages Disadvantages
Results
Short term Cheap, immediate benefit Inherently inequitable
Can be implemented by Increase energy use and greenhouse gas
measures individuals emissions
May be of limited public health benefit
Potential adverse health impacts of air
conditioning systems (building-
related symptoms); airborne
infections
Medium term Can be designed not increase Moderately expensive
energy consumption, can be Effectiveness proven in case studies but
measures implemented at building or uncertain at urban or regional scale
city scales
Long term Reduced energy consumption Costly (but cost effective?)
and greenhouse gas Long lead times
measures emissions; Inherently Requires political will (at international
equitable, with major level, in the case of climate change
potential health benefit mitigation)Mitigation – reduced carbon
emissions
• Low Carbon Building techniques
• Energy efficient design (Building Code)
- thermal envelope
- types of heaters
- “waste” heat
• Location
- solar gain
- transportExample – energy efficiency
Forms of Heating - efficiency
• Fire
Open fire 15%
Enclosed fire -free-standing fire 25%
-basic double burner 65%
-hi efficienty dbl 85%
Gas (flued / unflued) 80%
Kerosene
• Other
Electricity -fan/oil column ~100%
-heatpump >100%
Solar
• NoneAdaption at different societal levels
• Structural changes - shifting whole towns
• Food production
• Population movements - refugees
• Urban design
• Housing
• Regulation of markets in energy & water-
equity as well as efficiencyAdaptive capacity differs • Capability and functioning both important • Wealth, income, social and cultural capital increase ability to adapt • Adaptive responses should not increase health inequalities • Social gradients in health vs tipping point
Structural changes • Location of settlements (in relation to availability of secure water supplies, sea level rise and extreme events) • Infrastructure (water, electricity, transport, communications) and ability to withstand climate extremes • Such as floods…
Urban Form • 85% of New Zealander live in cities • Urban sprawl increases carbon emissions • Heat islands increase surrounding temperatures ~ 2°C, 5-11°C warmer than surrounding rural areas • People in suburbs and exurbs have longer commutes & less exercise, more obesity
Adaptation
• Building Design
(moderate cold & heat / pest screens / materials / )
• Location
(flood plains/ low-lying coastal / exposure )
• Behaviour
But … leaky buildings in New Zealand partially
caused by importing Mediterranean style design,
without:
*ensuring builders knew how to build it well
*accounting for more mobile land.Other examples of adaptation policy in
housing: a strong case for
• greater provision of extended family housing for
families in chain migration
• increases in social and health service
• higher proportion of social housing in all regions
(presently only 5%)
• ethnically integrated suburbs -strength of weak ties
• Household right to minimum amount of water
important for cleanliness and contagion control
• Greater use of grey water and rain water in cities
(with appropriate safeguards against mosquito
breeding)Vince (2009) in New Scientist: a high carbon world
Population movements:
NZ as lifeboat
• Worsening of extremes: floods, droughts,
storms, fires
• Sea level rise (esp Pacific islands, low lying
deltas)
• Reduced food security (esp Africa, Asia)
• Global solutions needed?Co-benefits of NZ shifting to a low-
carbon society
WIN/WIN policies
• More energy efficient housing benefiting health &
education & reducing energy costs
• Better support for active transport (cycling, walking)
will improve health (heart health, lower cancer risks
etc)
• Cleaner non-carbon energy sources will reduce air
pollution
• Improved urban design will have benefits for social
capital, mental health
• Lower carbon diets (less meat) will reduce risks of
heart disease and cancerConclusions
• Health effects of climate change should be an
important driver of adaptation policy
• Predominant health effects through extreme
weather events & infectious diseases
• Adaptation possible in urban form and housing
• Building ‘linking social capital’ important
• Co-benefits of moving to low-carbon economy
• Possibility of positive contribution to GDPConclusions • High carbon scenario likely to involve major global social disruption. • Can’t extrapolate health impacts in a simple linear fashion… • Need global optimisation of land use, exchange of migration rights and food security in return for protection of “terrestrial commons”?
References
• Hales S, Black W, Skelly C, Salmond C, Weinstein P. Social deprivation and
the public health risks of community drinking water supplies in New Zealand.
Journal of Epidemiology and Community Health 2003;57:581-583.
• Hales S, Woodward A. Potential health impacts and policy responses. In:
Chapman R, Boston J, Schwass M, editors. Confronting Climate Change:
Critical issues for New Zealand. Wellington: Victoria University Press,
2006:117-123.
• Hales S, Howden-Chapman P, Baker M, Menne B, Woodruff R, Woodward A.
Implications of global climate change for housing, human settlements and
public health. Review of Environmental Health 2007;22(4):295-302.
• Hennessy, K., B. Fitzharris, B.C. Bates, N. Harvey, S.M. Howden, L. Hughes,
J. Salinger and R. Warrick, 2007: Australia and New Zealand. Climate Change
2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group
II to the Fourth Assessment Report of the Intergovernmental Panel on Climate
Change, M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J. van der Linden and
C.E. Hanson, Eds., Cambridge University Press, Cambridge, UK, 507-540.
• Schellnhuber (Copenhagen talk)
http://climatecongress.ku.dk/presentations/webcasts/• “Confronting Climate Change: Critical Issues for
New Zealand” edited by Ralph Chapman,
Jonathan Boston & Margot Schwass esp chap 11
• Diamond, J. “Collapse: How societies choose to
fail or succeed”
• Housing & Health programme website including
sustainable heater report
www.wnmeds.ac.nz/healthyhousing.html
• Insulation study results www.bmj.com (search
“viggers” or “howden-chapman”)
• Energy Efficiency & Conservation Authority
http://www.eeca.govt.nz/
• Energy Studies Programme at OtagoYou can also read
