ESCI 274 Lecture 1: Climate and Health

4 types of environmental hazards

1) Chemical hazards

2) Physical hazards

3) Biological hazards

4) Cultural hazards

Chemical hazards

* Includes both artificial and natural chemicals
* Exposure can come from household chemicals such as pesticides

Physical Hazards

* The sun's ultraviolet radiation is an example
* Too much exposure increases risk of skin cancer

Biological hazards

* Exposure to organisms that cause disease
* Some mosquitoes are vectors for certain pathogenic microbes, including those that cause malaria

Cultural hazards

* Decisions about how we behave as well as constraints pushed on us by socioeconomic factors
* Smoking is a decision that increases the likelihood of cancer.

Linear dose-response curve

* The number of animals killed or otherwise affected rises with the dose
* The point at which 50% of animals are killed is labeled lethal dose-50 or LD50.

Dose response curve with threshold

Below the threshold doses have no measurable effect

U-shaped dose response curve

* At low doses, the benefits of vitamin A increase with dose
* Until a threshold is reached for no further benefits
* After the threshold is reached if dose continues to increase, negative effects will occur

Ecosystem services

1) **Supporting** - Nutrient cycling, soil formation, primary production

2) **Provisioning** - Food, fresh water, wood and fiber, fuel 

3) **Regulating** - Climate regulation, flood regulation, disease regulation, water purification

4) **Cultural** - Aesthetic, spiritual, educational, recreational  

Level of health impacts that result from environmental/climate change

1) Increase in air pollution related illness

2) Increase in injury, death, and illness from extreme weather events

3) Increase in water-borne diseases

4) Increase in food-borne diseases

5) Vector-borne illness

6) Heat related illness and death

7) Decrease in cold-related deaths

‘Base periods’ when compiling climate data/maps (and how it influences how the data can be interpreted)

* A popular climatological baseline period is a 30-year "normal" period, as defined by the WMO
* The current WMO normal period is 1961-1990, which provides a standard reference for many impact studies

Tipping point

The point of no return

The 9 tipping points that the world has crossed

1) **Amazon rainforest** - frequent droughts

2) **Arctic sea ice** – massive losses 

3) **Atlantic circulation** – a slowdown since 1950s 

4) **Boreal forest** – increase in fires 

5) **Coral reef** – mass die-offs 

6) **Greenland ice sheet** – ice loss accelerating  

7) **Permafrost** – melting  

8) **West Antarctic ice sheet**  

9) **Wilkes basin** – east Antarctica ice loss accelerating  

Primary impacts of climate change

**(Direct health impacts)** - Floods, heatwaves, landslide increased exposure due to UV rays, exposure to pollutants

Secondary impacts of climate change

**(Ecosystem mediated health impacts)** - Altered infectious disease risk, food yields (malnutrition, stunting), depletion of natural medicine, mental health (personal, community), impacts of aesthetic/ cultural impoverishment 

Tertiary impacts of climate change

**(Indirect, deferred, and displaced health impacts)** - Diverse health consequences of livelihood loss, population displacement (including slum dwelling), conflict, inappropriate adapting and migration.

Impact of climate chnage on human health diagram

Climate change and health diagram

Risk analysis diagram

Pathways of contaminants through the environment diagram

Biogeochemical Cycles diagram