Presentation on theme: "Kristie L. Ebi, Exponent Health Group"— Presentation transcript:
1Kristie L. Ebi, Exponent Health Group Vulnerability and Adaptation Assessments Hands-On Training Workshop Human Health SectorKristie L. Ebi, Exponent Health GroupFull references can be found in Chapter 11, Bibliography, of the Handbook.
2OutlineOverview of the potential health impacts of climate variability and changeHealth data to determine the current burden of climate-sensitive diseasesMethods and tools for V&A assessment in the health sectorMethods for determining a health adaptation baseline
3Overview of the Potential Health Impacts of Climate Variability and Change
4Topics Pathways for weather to affect health Potential health impacts of climate changeExtreme weather eventsEl Nino and diseaseTemperatureFloodsVector-borne diseasesDiseases related to air pollutionDiarrheal diseases
5Pathways from Driving Forces to Potential Health Impacts This shows the pathways by which climate change and other drivers can affect human health. Climate change will act through regional weather changes to affect health directly (temperature-related illness and death; and extreme weather-related health effects) and indirectly (air pollution-related health effects; water- and food-borne diseases; vector- and rodent-borne diseases; and mental, nutritional, infectious, and other health effects). The extent to which health impacts will be realized depends on the effectiveness of adaptation measures and on modulating influences (other drivers of health outcomes, such as population density in regions vulnerable to flooding).Corvalan et al., 2003
6Pathways for Weather to Affect Health: Example = Diarrheal Disease Distal CausesProximal CausesInfection HazardsHealth OutcomeTemperatureHumidityPrecipitationSurvival/ replicationof pathogens in theenvironmentConsumption ofcontaminated waterIncidence ofmortality andmorbidityattributableto diarrheaLiving conditions(water supply andsanitation)Contamination ofwater sourcesConsumption ofcontaminated foodThis diagram shows the various pathways by which weather and other factors can influence the morbidity and mortality due to diarrheal diseases.Contamination of food sourcesContact withinfected personsFood sources andhygiene practicesVulnerability(e.g. age andnutrition)Rate of personto person contactWHO
7IPCC TAR–Potential Health Impacts of Climate Change Any increase in climate extremes (storms, floods, cyclones) could increase the risk of infectious disease epidemics, particularly in low-income countriesIncrease in heatwaves, often exacerbated by increased humidity & urban air pollutionIncrease in the geographic range of potential transmission of malaria & other vector-borne diseasesIncrease in water- and food-borne diseasesThe severity of impacts will depend on the capacity to adapt & its effective deployment
8Drivers of Health Issues Population densityUrbanizationPublic health infrastructureEconomic and technologic developmentEnvironmental conditionsPopulations at riskPoorChildrenIncreasing population of elderly residentsImmunocompromisedClimate change is not the sole determinant of climate-sensitive diseases. This lists some other important drivers.
12El Nino starts El Nino stops This shows the relationship between the beginning of an El Niño and the number of cholera cases in Uganda. El Niño events have been shown to be associated with outbreaks of other diseases such as malaria.Dr. Githeko, personal communication
13Climate Change May Entail Changes in Variance, as Well as Changes in Mean Interactions between changes in the mean and variability of weather variables complicate projecting possible future trends in extreme events. Assuming a normal distribution of surface temperature, one can envision three scenarios of increasing temperatures. In the first scenario, there is a simple shift in mean temperature without a change in the variance (e.g., the shape of the curve would remain the same). If this occurs, then there would be a decrease in cold weather and an increase in both hot and record hot weather. A second scenario is an increase in the variance without a change in mean temperature; this would result in increasing cold and hot weather, with a decreasing frequency of weather that could be considered average under the previous climate (e.g., the shape of the curve would become flatter). Finally, if there is a shift in both the mean and the variance, then there would be small decrease in cold weather and a significant increase in both hot and record hot weather.Folland et al., 2001
14Temperature Extremes in the Caribbean, 1955-2000 These data were presented by Michael Taylor (University of the West Indies) at a workshop in Barbados on small island states organized by WHO, WMO, and UNEP in May 2002 (workshop report available from WHO; Aron et al., 2003). The graphs shows the trend for minimum and maximum temperatures in the Caribbean, along with the percentage of days that temperature was greater than the 90th percentile (for minimum and maximum temperature), relative to the period Temperature extremes have been increasing since the late 1950s. These observed changes are considered consistent with patterns related to climate change.
15Climate Variability and Change Impacts in the Caribbean DATECOUNTRYEVENTDEATHESTIMATED COSTS(US$ million, 1998)1974HondurasHurricane Fifi7,0001,3311982/3Bolivia, Ecuador, PeruEl Niño5,6611997/98Bolivia, Colombia, Ecuador, Peru6007,6941998Central AmericaHurricane Mitch9,2146,008Dominican RepublicHurricane Georges2352,193Cuba6N/A1999VenezuelaLandslide25,000Fuente: ECLAC, América Latina y El Caribe: El Impacto de los Desastres Naturales en el Desarrollo, , LC/MEX/L.402; OFDA, Venezuela- Floods, Fact Sheet #10, 1/12/ 2000.
16Mechanisms by Which Above Average Rainfall Can Affect Health EventDescriptionPotential Health ImpactHeavy precipitation“Extreme event”Increased or decreased mosquito abundanceFloodRiver/stream over tops its banksProperty or crops damagedAbove plus contamination of surface waterCatastrophic flood/disasterAbove plus increased risk of respiratory and diarrhoeal disease, injuries, etc.Kovats et al., 2003
17Health Impacts of Floods Immediate deaths and injuriesNonspecific increases in mortalityInfectious diseases – leptospirosis, hepatitis, diarrheal, respiratory, and vector-borne diseasesExposure to toxic substancesMental health effectsIncreased demands on health systemsFlooding results in more than immediate deaths and injuries, as listed on this slide.Philip Wijmans, LWF/ACT Mozambique, March 2000
18Mechanisms by Which Drought Can Affect Health DescriptionPotential Health ImpactSoil moisture decreasesChanges in vector abundanceDecreased crop productionDepends on socioeconomic factorsReduction in food or water supply and qualityFood shortage, illness, malnutrition, increased risk of diseaseFood shortage leading to deathsDeath, starvation, risks associated with population displacementKovats et al., 2003
19Examples of Environmental Changes and Possible Effects on Infectious Diseases Example DiseasePathway of EffectDams, canals, irrigationMalariaIncrease breeding sites for mosquitoesUrbanizationCholeraDecreased sanitation & hygiene, increased water contaminationReforestationLyme diseaseIncrease tick hosts, outdoor exposureOcean warmingRed tideIncrease toxic algal bloomsPatz et al., 2003Wilson 2001
20Factors that Influence the Range and Prevalence of Infectious Diseases Sociodemographic influencesHuman travel, trade, and migrationDisease control effortsDrug resistanceNutritionEnvironmental influencesLand-use, including deforestation, agricultural development, and urbanizationEcological influences
21Temperature and Precipitation Effects on Vector- and Rodent-Borne Diseases Survival and reproduction rate of the vectorTime of year and level of vector activity, specifically the biting rateRate of development and reproduction of the pathogen within the vector
22Main Types of Transmission Cycles for Infectious Disease Patz et al., 2003
23Potential Transmission of Schistosomiasis, Jiangsu Province Yang et al., 2005
24Climate Change and Malaria under Different Scenarios (2080) Increase: East Africa, Central Asia, Russian FederationDecrease: Central America, Amazon [within current vector limits]Van Lieshout et al. 2004A1A2Source: Van Leishout et al., 2004.Based on the MIASMA model (V2.2) developed by Martens and colleagues. The model links GCM climate scenarios with an impact module that applies the formula for the basic reproduction rate to calculate the transmission potential of the malaria mosquito population, and to estimate the population at risk. The population at risk was defined as the total population living in an area where conditions were suitable for malaria transmission as defined by the transmission potential, and an average monthly precipitation of 80 mm. The reference scenario included population growth and kept the climate conditions the same as in the baseline climatology of The model estimates climate suitability for an average year and the suitability for stable or annual transmission. The model assumes the current level of adaptation to malaria (countries were classified into one of six groups based on expert judgment).Estimates of the additional population at risk for more than 1 consecutive month of transmission by the 2080s ranged from more than 220 million (A1) to over 400 million (A2) when climate factors and population growth are considered in the model. The figure shows, under each scenario, the change in risk classified by the changes in the number of consecutive months of transmission (> +2, +2, -2, < -2).B1B2Van Lieshout et al. 2004
25China Haze 10 January 2003This aerial photo from NASA gives an indication of the importance of dust storms. Few studies have been conducted of the extent of illness and death occurring during dust storms.NASA
26Effect of Temperature Variation on Diarrheal Incidence in Lima, Peru Daily Diarrhea AdmissionsDaily TemperatureDiarrheal diseases are also climate sensitive. These graphs show the variation in daily diarrheal admissions with the variation in daily temperature. Adjusting statistically for the long-term trend and for other seasonal effects, diarrhea increases by 8% for each 1°C increase in temperature.Where the dose-response relationship has been quantified, similar patterns have been observed in other developing countries, i.e., 3% increase for each 1°C increase in Fiji.A dose-response relationship can be applied to temperature change maps for different climate change scenarios.Diarrhea increases by 8% for each 1ºC increase in temperatureCheckley et al., 2000
27ResourcesMcMichael, A.J., D.H. Campbell-Lendrum, C.F. Corvalan, K.L. Ebi, A. Githeko, J.D. Scheraga, and A. Woodward (eds.) Climate Change and Human Health: Risks and Responses. WHO, Geneva.Summary pdf available atKovats, R.D., K.L Ebi, and B. Menne Methods of Assessing Human Health Vulnerability and Public Health Adaptation to Climate Change. WHO/Health Canada/UNEP.Pdf available at
28Health Data to Determine the Current Burden of Climate-Sensitive Diseases
29Questions to be Addressed What climate-sensitive diseases are important in the country or region?What is the current burden of these diseases?What factors other than climate should be considered?Water, sanitation, etc.Where are data available?Are health services able to satisfy current demands?
30Health Data SourcesWorld Health Report provides regional-level data for all major diseasesAnnual data in Statistical AnnexWHO databasesMalnutritionWater and sanitationMinistry of HealthDisease surveillance/reporting branch
31Health Data Sources – Other UNICEF atCRED-EMDAT provides data on disastersMission hospitalsGovernment district hospitals
32Indonesia Total population = 219,883,000 Annual population growth rate = 1.4%Life expectancy at birth = 67 yearsUnder age 5 mortality rate = 41/1,00070% of 1-year-olds immunized with 3 doses of DTP3.2% of gross domestic product spent on healthThis is an example of data from the World Health Report.WHO, 2005
33Methods and Tools for V&A Assessment in the Health Sector
34Methods and Tools Qualitative assessments Methods of assessing human health vulnerability to climate changeWHO Global Burden of Disease Comparative Risk AssessmentEnvironmental Burden of DiseaseMIASMAOther models
35Qualitative Assessments Available data allow for qualitative assessment of vulnerabilityFor example, given current burden of diarrheal diseases and projected changes in precipitation, will vulnerability remain the same, increase, or decrease?
36Methods of Assessing Human Health Vulnerability and Public Health Adaptation to Climate Change Publication available from WHO European Centre for Environment and Health.Kovats et al., 2003
37Methods for:Estimating the current distribution and burden of climate-sensitive diseasesEstimating future health impacts attributable to climate changeIdentifying current and future adaptation options to reduce the burden of diseaseKovats et al., 2003
38Estimate Potential Future Health Impacts Requires using climate scenariosCan use top-down or bottom-up approachesModels can be complex spatial models or be based on a simple exposure-response relationshipShould include projections of how other relevant factors may changeUncertainty must be addressed explicitlyKovats et al., 2003
39Case Study: Risk of Vector-Borne Diseases in Portugal Four qualitative scenarios developed of changes in climate and in vector populationsVector not presentFocal distribution of vectorWidespread distribution of vectorChange from focal to potentially regional distributionExpert judgment determined likely risk under each scenario for 5 vector-borne diseasesCasimiro et al., 2006
41Sources of Uncertainty DataMissing data or errors in dataModelsUncertainty regarding predictability of the systemUncertainty introduced by simplifying relationshipsOtherInappropriate spatial or temporal dataInappropriate assumptionsUncertainty about predictive ability of scenariosKovats et al., 2003
42Estimating the Global Health Impacts of Climate Change What will be the total potential health impact caused by climate change (2000 to 2030)?How much of this could be avoided by reducing the risk factor (i.e. stabilizing greenhouse gas (GHG) emissions)?McMichael et al., 2004
43Comparative Risk Assessment TimeGreenhouse gas emissions scenarios2020s2050s2080sGlobal climate modelling:Generates series of maps of predicted future climateThe comparative risk assessment approach used scenarios of greenhouse gas emissions, which were input into global climate models, the output of which was used with health impact models to estimate the total burden of disease under various scenarios. The burden of disease estimates generated were numbers of deaths and disability-adjusted life years lost (DALYs) that take into account both morbidity and mortality associated with the health outcome.2080s2050s2020sHealth impact model:Estimates the change in relative risk of specific diseasesMcMichael et al., 2004
44Criteria for Selection of Health Outcomes Sensitive to climate variationImportant global health burdenQuantitative model available at the global scaleMcMichael et al., 2004
45Health Outcomes Considered Outcome ClassIncidence / prevalenceOutcomeDirect effects of heat and coldIncidenceCardiovascular disease deathsFoodborne & waterborne diseasesDiarrhea episodesVector-borne diseasesMalaria casesNatural disastersDeaths due to unintentional injuriesOther unintentional injuriesRisk of malnutritionPrevalenceNon-availability of recommended daily calorie intakeMcMichael et al., 2004
46Exposure: Alternative Future Projections of GHG Emissions Unmitigated current GHG emissions trendsStabilization at 750 ppm CO2-equivalent by the year 2210Stabilization at 550 ppm CO2-equivalent by the year 2170Average climate conditions for (WMO climate normal baseline)Source: UK Hadley Centre modelsMcMichael et al., 2004
47Estimated Mortality (000s) Attributable to Climate Change, 2000 Mal-nutritionDiarrheaCVDAll CausesDeaths / MillionSEAR-B127.9SEAR-D522278065.8McMichael et al., 2004
48Climate scenarios, as function of GHG emissions The results for diarrhea show relatively modest increases in relative risks the developing regions of the world. However, because the absolute number of people at risk is large, these suggest that many more people could be at risk under these climate change scenarios. Further, this is a relatively conservative estimate, because it is looking at direct temperature effects only, ignoring possible effects on diarrhea acting through lack of clean water, etc.
49ConclusionsClimate change may already be causing a significant burden in developing countriesUnmitigated climate change is likely to cause significant public health impacts out to 2030Largest impacts from diarrhea, malnutrition, and malariaUncertainties include:Uncertainties in projectionsEffectiveness of interventionsChanges in nonclimatic factorsMcMichael et al., 2004
50Environmental Burden of Disease A. Prüss-Üstün, C. Mathers, C. Corvalan, and A. Woodward Introduction and Methods: Assessing the Environmental Burden of Disease at National and Local Levels [pdf available atClimate change document will be published soon
51Climate and Stable Malaria Transmission Climate suitability is a primary determinant of whether the conditions in a particular location are suitable for stable malaria transmissionA change in temperature may lengthen or shorten the season in which mosquitoes or parasites can surviveChanges in precipitation or temperature may result in conditions during the season of transmission that are conducive to increased or decreased parasite and vector populationsIn Africa, stable malaria refers to falciparum malaria, the most serious form of malaria. More than 90% of malaria in Africa is falciparum malaria.
52Climate and Stable Malaria Transmission (continued) Changes in precipitation or temperature may cause previously inhospitable altitudes or ecosystems to become conducive to transmission. Higher altitudes that were formerly too cold or desert fringes that were previously too dry for mosquito populations to develop may be rendered hospitable by small changes in temperature or precipitation.
53Relationship between Temperature and Daily Survivorship of Anopheles This graph shows the proportion of Anopheles mosquitoes surviving for one day at different mean temperatures. The proportion of surviving mosquitoes declines rapidly over mean temperatures of about 37°C. The proportion of mosquitoes surviving two days is a function of how many survived the first day, plus any new mosquitoes added to the population the first day.
54Relationship between Temperature and Time Required for Parasite Development This graph shows the number of days required for malaria parasite development as a function of mean temperature. At mean temperatures less than 21°C, mosquitoes have to survive at least 20 days after they acquire the malaria parasite to be infective. As mean temperature rises to about 21°C, the time required becomes shorter. At 30°C, it takes just a few days for mosquitoes to become infective.
55Proportion of Vectors Surviving Time Required for Parasite Development This graph shows the proportion of vectors surviving long enough for the malaria parasite to develop at different mean temperatures. At about ºC, somewhat more than one-third of vectors survive long enough to pass along the parasite.
56and regional and country-level maps MARA/ARMA was a large project designed to map malaria risk in Africa. The website provides a wealth of information on malaria prevalence and population data at regional and country levels. Inquiries to the website are answered quickly.The website [http://www.mara.org.za] contains prevalence and population data,and regional and country-level maps
57MARA/ARMA analyzed the listed environmental data in relation to malaria prevalence.
58MARA/ARMA ModelBiological model that defines a set of decision rules based on minimum and mean temperature constraints on the development of the Plasmodium falciparum parasite and the Anopheles vector, and on precipitation constraints on the survival and breeding capacity of the mosquitoCD-ROM $5 for developing countries or can download components from website:
59This map, from the MARA/ARMA website, shows the distribution of endemic malaria in Africa (endemic means that malaria is always present, although not necessarily for all months of the year). As stated, the model is based on the biological constraints on the vector and parasite.
60MIASMAModeling Framework for the Health Impact Assessment of Man-Induced Atmospheric ChangesMIASA was written by Dr. Pim Martens A fee of US$ 5 is required for a self-extracting CDIncludes modules for thermal stress, malaria, dengue, and schistosomiasisSelect IPCC scenario and GCM
61Other Models CiMSiM and DENSim for dengue Weather and habitat-driven entomological simulation model that links with a simulation model of human population dynamics to project disease outbreaks
62India’s Initial National Communication: Goals To identify, analyze, and evaluate the impacts of climate variability and change on natural ecosystems, socioeconomic systems, and human healthTo assess the vulnerabilities, which also depend on the institutional and financial capacities of the affected communitiesTo assess the potential adaptation responsesTo develop technical, institutional, and financial strategies to reduce vulnerability
63India’s Initial National Communication Temperature-related mortalityVector-borne diseasesChanging patterns of diseases – malaria, filaria, kala-azar, Japanese encephalitis, dengueHealth effects of extreme weatherDiarrhea, cholera, and poisoning caused by biological and chemical contaminants in waterDamaged public health infrastructure due to cyclones/floodsSocial and mental health stress due to disasters and displacementsHealth effects due to insecurity in food production
65Projected Changes in Number of Months Malaria Can Be Transmitted
66Factors Affecting Malaria Distribution and Prevalence in India ClimateUrban settlementsPovertyIrrigationAgricultural practicesLand-use change
67Methods for Determining a Health Adaptation Baseline
68Questions for Designing Adaptation Policies and Measures Adaptation to what?Is additional intervention needed?What are the future projections for the outcome? Who is vulnerable?On scale relevant for adaptationWho adapts? How does adaptation occur?When should interventions be implemented?How good or likely is the adaptation?
69Current and Future Adaptation Options What is being done now to reduce the burden of disease? How effective are these policies and measures?What measures should begin to be implemented to increase the range of possible future interventions?When and where should new policies be implemented?Identify strengths and weaknesses, as well as threats and opportunities to implementationKovats et al., 2003
70Public Health Adaptation Existing risksModifying existing prevention strategiesReinstitute effective prevention programs that have been neglected or abandonedApply win/win or no-regrets strategiesNew risks
71Options for Adaptations to Reduce the Health Impacts of Climate Change Health OutcomeLegislativeTechnicalEducational-advisoryCultural & BehavioralThermal stressBuilding guidelinesHousing, public buildings, urban planning, air conditioningEarly warning systemsClothing, siestaExtreme weather eventsPlanning laws, economic incentives for buildingUrban planning, storm sheltersUse of storm sheltersVector-borne diseasesVector control, vaccination, impregnated bednets, sustainable surveillance, prevention & control programmesHealth educationWater storage practicesWater-borne diseasesWatershed protection laws, water quality regulationScreening for pathogens, improved water treatment & sanitationBoil water alertsWashing hands and other behavior, use of pit latrinesSource: Chapter 9 (Human Health) in the IPCC Third Assessment Report.McMichael et al. 2001
72Screening the Theoretical Range of Response Options – Malaria Ebi and Burton, submitted
73Analysis of the Practical Range of Response Options – Malaria Ebi and Burton, submitted