Outline Background –Human energy balance –Strategies to temperature changes Morbidity –Heat Waves –Flooding –Famine Disease –Malaria

IPCC (2007) Working Group 2 Report How climate change affects health

Heat Waves Associated with short-term increases in mortality Have been increasing in frequency Mortality displacement is a factor –People close to death will die sooner in a heat wave –Drop off in deaths after the heat wave

Human Adaptability to Heat Humans maintain near constant core temperature through various adaptive strategies: –Physiological (sweating) –Acclimatization (adjustment to new conditions over time) –Alteration of food intake –Changing when you do things –Migration –Clothing –Use energy for A/C or heating

Human Energy Balance Storage change = 0 over time to maintain temperature balance Metabolic Rate Incoming shortwave Longwave Radiation Convection Evaporation Storage

Clothing Impact The “private climate” Quantified by estimating the resistance to thermal transfer: Body Temp. Air Temp. Body Area Incoming short wave Metabolic Rate Dry Heat Flux = (wind speed) 0.5

Simplified Clothing Index

Acclimatization Evidence that some populations have become less sensitive to temperature extremes –USA ( ) –South Carolina (since 1970s) Physiological responses include: –More efficient heat loss through sweat –Readjustment of temperature preference toward the extreme values Leads to less discomfort, better work performance, sense of better well being

Flooding and Health Effects Large numbers of fatalities from the events themselves –Bangladesh Post-event impacts –Digestive diseases –Chemical contamination (e.g. Katrina) –Mental disorders (anxiety, depression) Higher impacts on poor –More live in flood prone areas

Drought Diminishes diversity in diet and reduces overall food consumption Malnutrition –Increases risk of acquiring and dying from infectious disease May cause mass migration (rural to urban) –Increase in communicable disease

Climate Model Projections

Food Safety Studies have shown a linear increase in food poisoning with increase in temperature Higher temperatures increase contact between food and pests (flies, cockroaches, rodents) More ocean toxins (Harmful Algal Blooms) contaminate shellfish

Water Supply Water access already a global concern –2 billion + do not have access to clean water –Leads to disease, malnutrition, infant mortality

Water Supply Climate extremes (projected to increase) stress water supply systems Lower river flows increases pathogen proportion Extreme rain/runoff events may increase water borne disease –Curriero et al. 2001

Vector Borne Diseases Transmitted through bites –Mosquitoes, ticks, bugs, some flies Tick populations have shifted north (Sweden, Canada) and up (Czech Republic) Evidence of earlier arrival of mosquitoes

Malaria 515 million cases each year in tropics and subtropics –1-3 million deaths Conflicting results on malaria trends and how they relate to climate –Some evidence that high minimum temperatures in preceding months mean more malaria (Ethiopia)

Future Vulnerability to Climate Change Factors –Existing burden of disease and disability –Aging of the population –Population explosion From 6.4 bil to 9 bil by mid-21 st century Highest in poor countries –Urbanization Heat island effect, more efficient disease transfer –Socio-economic Rich get richer, poor get poorer