ENVM3115 Lecture Notes - Lecture 5: Arable Land, Stoma, Market Failure
1 Jun 2018
School
Department
Course
Professor
Social and Economic Consequences and Responses
Recap extreme weather events
• Climate change does not cause weather events
- It changes the energy available to them
• Extreme weather event: exceeds the 90th percentile of variability as estimated from
base period
• Heatwaves in particular have very strong climate change signature
• Lots of uncertainty around exactly how climate change will impact the extreme events
• Predictions often show there will be greater variability
Heatwaves: become more frequent
Cyclones: no change sin frequency, but more severe
Tornadoes: could change in location and seasonality
Rainfall: more intense bursts of rain; perhaps greater gaps between rain events (=more
drought)
→ high variable & uncertain
Fire: significant increase in Forest Fire Danger Index
Permafrost: thaw, releasing methane and C02
Sea level rise
Regional Climate Shifts
• Changes in temperature and moisture availability and the poleward shift of isotherms
- Changes in agricultural suitability – cropping, grazing and viticulture
- Water availability for irrigation
- Economically important ecosystem and species range shifts in life cycle events
(e.g. fisheries)
• New species e.g. crocodiles, Irukandji jellyfish
• Changes in risk of damage from extreme weather events and sea level rise
Sea level rise
• Using 25-year precision satellite altimeter
• GMSL has risen 2.9mm/y
• Accelerating at 0.084 +/- 0.02 mm/y^2
• Could rise 65+/- 12 cm by 2100
• Equates to IPPC 5th Assessment report projections
Wet Bulb Globe temperature
• Measure of heat stress in direct sunlight
• Takes into account:
- Temperature
- Humidity
- Wind speed
- Sun angle
- Cloud cover (solar radiation)
• Military use WGBT to guide managing workload in direct sunlight
Human health – heat stress
• Body temperature is usually sustained in hot weather by sweating
• Fatal heat exhaustion in humans if local wet-bulb ambient temp exceeds 37˚c
• Core body temp = 37˚c. if >38˚c for several hours → heat stroke
• >42˚c even for short time is fatal
Heat Stress
• Conditions that prevent body heat dissipation
- Too hot
- Too humid
- Both
• 7 vital organs can be affected
• 5 psychological mechanisms
• 27 pathways heat can lead to organ failure and death
• exposure to heat → hypothalamus → cardiovascular response → dilates blood vessels
to redirect blood from core to periphery
→ can lead to inadequate blood flow to other organs
• cell damage from thermal & chemical injury
• dehydration (=thickens blood → increase coronary thrombosis & stroke)
Most vulnerable:
• compromised thermoregulatory capacity
- old, young, sick
• limited socio-economic capacity
• urban residents
• outdoor workers
→ but could happen to anyone
• power failures can increase vulnerability
Heatwaves in Australia
• Major heatwaves have caused more deaths since 1890 than bushfires, cyclones,
earthquakes, floods and severe storms combined
• During the heatwave in SE Australia in Jan/Feb 2009
- Emergency call outs
- Cases involving heat related illness
- Cardiac arrests
- 374 excess deaths were recorded, a 62% increase from previous year
• Mortality data: past four decades, increase in no. of deaths in summer, compared to
those in winter
Heat Stress
• Some parts of the world may become inhabitable
• Change in the number of ‘black flag’ days over 32.2˚c WBGT
Human health – trauma
• NSW study: decrease in annual rainfall by c. 300mm could increase suicide rate by
8%
• SA: admissions for mental, behavioural and cognitive disorders have been found to
increase by around 7% during heatwaves
Human health – disease
• Expansion of tropical diseases – malaria and dengue fever
• Food borne bacterial infections – salmonellosis
• Water borne infections – diarrhoea and parasites – cryptosporidium and giardia
• Animal borne disease – Lyme disease
Water supply and security
“Changes in water quantity and quality due to climate change are expected to affect food
availability, stability, access and utilisation.”
“Climate change affects the function and operation of existing water infrastructure – including
hydropower, structural flood defences, drainage and irrigation systems – as well as water
management practices.”
Food production and security
• Pests and diseases
• Biotechnology – genetic engineering and technologies for increased productivity and
pest, disease, drought and inundation resistance
• C02 effects on crops (increase leaf mass, reduced stomata size, reduced protein
content
• Arable land availability
• Extra-territorial farming/grazing land purchases
Document Summary
Recap extreme weather events: climate change does not cause weather events. Cyclones: no change sin frequency, but more severe. Rainfall: more intense bursts of rain; perhaps greater gaps between rain events (=more drought) Fire: significant increase in forest fire danger index. Regional climate shifts: changes in temperature and moisture availability and the poleward shift of isotherms. Changes in agricultural suitability cropping, grazing and viticulture. Economically important ecosystem and species range shifts in life cycle events (e. g. fisheries: new species e. g. crocodiles, irukandji jellyfish, changes in risk of damage from extreme weather events and sea level rise. Sea level rise: using 25-year precision satellite altimeter, gmsl has risen 2. 9mm/y, accelerating at 0. 084 +/- 0. 02 mm/y^2, could rise 65+/- 12 cm by 2100, equates to ippc 5th assessment report projections. Wet bulb globe temperature: measure of heat stress in direct sunlight, takes into account: Cloud cover (solar radiation: military use wgbt to guide managing workload in direct sunlight.
