Climate Change and Human Population Health: Past, Present, Future

1. Climate Change and Human Population Health: Past, Present, Future Department of Defence, June 2013 Tony McMichael, AO Emeritus Professor (Population Health) National Centre for Epidemiology and Population Health The Australian National University tony.mcmichael@anu.edu.au

2. Deaths Attributable to Climate Change: Year 2000 Estimated annual deaths attributable to climate change from: malnutrition (~80K), diarrhoea (~50K), malaria (~20K), flooding (~3K) 14 WHO statistical regions scaled by estimated annual mortality (selected causes, in 2000) due to change in climate during 1970-2000. (Patz et al, 2007: based on McMichael, et al, 2004)

3. Climate Change: Health Impact Pathways Physical systems (river flow, vegetation, soils, ocean temp, etc.) Economic/social impacts: infrastructure, economic productivity, jobs, coastal displacement, resource-related conflict/warfare Biological & ecological processes Climate Change: Impacts Indirect (‘secondary’) impacts, ecologically-mediated: changes in food,water,mosquitoes Direct (‘primary’) impacts (extreme weather, heatwaves, air pollution) • Human Health • Injuries/deaths; mental stress • Thermalstressimpacts Indirect (‘tertiary’) health impacts – socially & politically mediated • Infectious diseases • Under-nutrition • Mentalstresses • Trauma/deaths

4. Normal Range Dry Wet 5-year running mean yield deviation Spring Barley Yield (deviation, %) Rainfall Index, April-June Relationship between Rainfall Index (combines rainfall and temperature) in Spring (April-June) and Barley Yields in Czech Republic since 1940s. Brazdil et al, 2008

5. CLIMATE CHANGE to 2050: MODELLED CHANGES IN CEREAL GRAIN YIELDS (due to temperature and soil moisture) Poor Countries are Projected to Fare Worst 20 • Not including climate-related: • Flood/storm/fire damage • Droughts – range, severity • Pests (climate-sensitive) • Infectious diseases (ditto) 36 80 64 Percentage change in yields to 2050 -50 -20 0 +20 +50 +100 UN Devt Prog, 2009

6. Climate Change: Diverse Influence Paths on Infectious Diseases eg. dengue, malaria; Ross River virus, Lyme disease eg. nutrition-related immune function Social-demographic influences

7. Dengue Fever: Estimated ‘receptive’ region for Ae. aegypti mosquito vector, under alternative climate-change scenarios for 2050 . . Darwin . Katherine . Cairns . . Broome Townsville . . Port Hedland . Mackay Risk region for medium emissions scenario, 2050 . . Katherine Rockhampton . Cairns . Carnarvon . Broome Townsville . Port Hedland Mackay . . Current risk region for dengue transmission Rockhampton . Darwin . Brisbane . Katherine . Cairns . . Broome Townsville . Port Hedland . Mackay . Risk region for high emissions scenario, 2050 Rockhampton Carnarvon NCEPH/CSIRO/BoM/UnivOtago, 2003

8. Climate Change Influences on Health in Australia Already apparent: baseline risks amplified by underlying climate change Uptrend in av annual no. of heat-days  deaths, hospitalisations Increases in no./severity bushfires  injury/death, resp. hazard, mental health Severe flooding (due to increased sea-surface temp, increased rainfall?) Probable current health impacts: butnot yet clearly identified Rising rates of some food-borne enteritis (diarrhoeal) diseases Altered (urban) air quality: ozone formation, aeroallergens Mental health impacts, esp. in some (drying) rural regions: e.g. MD Basin Predicted future health impacts More extreme weather events  trauma/deaths, infectious disease, depression Water shortages, affecting food yields, domestic hygiene Mosquito-borne infections – shifts in range and seasonality: Dengue, Ross River virus, Barmah Forest virus, Japanese encephalitis, etc. Increased thermal stress at work, esp. in outdoor workers and under-ventilated factories: accidents/injuries, organ damage; reduced work capacity

9. Changes in Average Northern Hemisphere Temperature over the Past 11,000 Years AJ McMichael, 2012) Modelled range of projected global temperature rise to 2100 (vs.1990) = + 2-5oC +4 +3 +2 +1 0 -1 -2 -3 Variations in NH Temp, oC (rel. to Holocene average) Holocene Holocene Climatic Optimum I, II Roman Warm Period Mediaeval Warm Period, Europe Faster warming since 1975 Sahara dries Drought & cooling in East Mediterranean region Little Ice Age: Europe, China Early agrarian societies begin to form: Egypt, Sumer, southern China Post-glacial warming following Younger Dryas cooling, 12.8-11.6K BP Acute cooling: Tambora eruption 1815 Acute cooling: 536 CE ‘Event’ 11 10 9 8 7 6 5 4 3 2 1 02 4 6 8 10 12 14 16 18 20 22 Millennia BCE (1000s of yrs) Centuries CE (100s of yrs) BCE/CE

10. Europe’s coldest period, 1570-1660, during Little Ice Age Food yields down, grain prices tripled … conflict , war, displacement Cold Period 1570-1660 European Temperature Variation standardised units Nth Hemi-sphere Temperature Variation oC Famine-years/decade x 2 Epidemic rate x 3 Adult height ↓1.5cm Rate of Migrations, Europe War Fatality Index, Europe 1500 1550 1600 1650 1700 1750 1800 Zhang et al., PNAS, 2011

11. Temperature, Conflict, Warfare within China, 1000-1940: Relationship to Fall of Dynasties Five (grey) periods of cold in China Northern (> 20oN) Hemisphere temperature C variations, o ( cf 1961 - 90 av.) The ‘Little Ice Age’ 1000 1200 1400 1600 1800 2000 Wars No. of internal Rebellions wars (per decade) Population size N. Song S. Song Yuan Ming Qing (millions) 1000 1200 1400 1600 1800 2000 Adapted from Zhang et al, 2009

12. Civil Conflicts, 1950-2004, in Countries Affected or Not/Little Affected by ENSO Affected (n= 93 countries) (n= 82 countries) Annual Civil Conflict Rate (% of countries embroiled) Probability of new civil conflicts breaking out in El Niño years is double that seen in cooler La Niña years Weaker Stronger El Niño Index (NINO3: May-Dec average Sea-Surface Temperature) Hsiang et al., Nature 2011

13. Now, over to Colin Butler ………