Risks and Opportunities of Climate Change for Humans and Ecological Systems

Climate change creates both risks (harmful outcomes) and opportunities (potential benefits) for humans and ecological systems. VCE Environmental Science requires analysis of these at a specific region or location, across five key areas.

1. Increase in Range of Exotic Species

Risk

• Warmer temperatures allow invasive species to expand their geographic range into previously inhospitable areas
• Species previously limited by cold winters can now overwinter in new regions
• Pathogens and parasites may spread into new host populations with no prior immunity
• Examples:
• Red imported fire ants (Solenopsis invicta): warming expands suitable habitat southward in Australia
• Cane toads: range expanding southward into NSW and potentially Victoria
• Varroa mite (European honeybee parasite): warmer conditions may enable spread in Australia
• New plant diseases reaching previously frost-protected areas

Opportunity

• Minimal — range expansion of exotic species is overwhelmingly negative for biodiversity

2. Changes in Plant Growing Seasons and Animal Breeding Cycles

Changes Observed

• Lengthening growing seasons in cooler regions: earlier spring green-up, later autumn senescence
• Earlier breeding in warm-season animals: some shorebirds, frogs and mammals breeding earlier
• Extended fire seasons in fire-prone regions due to longer periods of dry, hot conditions
• Shorter cold winters affecting vernalisation requirements for crops and native vegetation

Risks

• Plants and animals that evolved together may go out of synchrony if they respond differently to warming
• Fire danger periods extending = more fire risk, threatening biodiversity and property
• Coral bleaching risk increases as warm seasons lengthen (bleaching occurs when SST is elevated for extended periods)

Opportunities (regional)

• Some high-latitude or high-altitude regions benefit from longer growing seasons
• New crop varieties may become viable in cooler areas
• However, these gains are typically smaller than losses in more productive lower-latitude regions

3. Phenological Changes for Plant-Pollinator Interactions

Phenology is the study of the timing of biological events (flowering, migration, emergence).

The Mismatch Problem

• Climate change affects different species’ phenology at different rates
• If flowering times advance faster than pollinator emergence, or vice versa, a phenological mismatch occurs
• Plants may flower before their pollinators have emerged → reduced pollination → lower seed set → reduced plant reproduction

Examples

• European studies show many flowering plants advancing flowering dates by 2–10 days per decade
• Some bee species show lesser advancement in emergence dates → increasing mismatch
• Victorian example: Alpine daisies and their specialist native bee pollinators may fall out of synchrony as warming advances spring temperatures

Consequences

• Reduced seed production and reproduction in flowering plants (including food crops)
• Reduced food availability for pollinators
• Cascading effects on animals that depend on seeds and fruits
• Risk of local extinctions if mismatches are severe

4. Increasing Risks to Coastal Infrastructure from Sea Level Rise

Mechanisms

• Chronic inundation: Low-lying areas flooded more frequently during high tides (nuisance flooding)
• Storm surge amplification: Higher baseline sea levels mean storm surges reach further inland
• Erosion: Wave energy reaching higher up beaches and into dunes
• Saltwater intrusion: Fresh groundwater replaced by saline water

Australian Coastal Infrastructure at Risk

• Properties: CSIRO estimates over 160,000 Australian homes are at risk from 1.1 m sea level rise
• Infrastructure: Roads, rail, ports, airports, wastewater treatment facilities
• Tourism assets: Beaches, Great Barrier Reef infrastructure
• Examples: Pacific Island nations face potential abandonment; Tuvalu, Kiribati at extreme risk

Opportunity

• Forces upgrade and redesign of coastal infrastructure with greater resilience
• Investment in coastal restoration (mangroves, reefs) as natural buffers

5. Reduction in Agricultural Production Due to Warmer and Drier Conditions

Mechanisms

• Heat stress: Crops above their thermal optimum have reduced yields; livestock productivity declines
• Drought: Reduced and more variable rainfall reduces soil moisture and irrigated water availability
• Altered growing seasons: Frost-dependent crops (some fruits) may be affected by fewer chill hours
• Increased pest and disease pressure: Warmer conditions favour some agricultural pests and fungal pathogens

Australian Agricultural Impacts

• Wheat production in southern Australia projected to decline significantly under warming and drying trends
• Dairy and beef production facing heat stress and reduced pasture productivity
• Grape growing regions shifting southward (e.g. Tasmanian wine production increasing)
• Murray-Darling Basin irrigation agriculture under pressure from reduced river flows

Opportunity

• Some currently frost-limited crops may become viable in cooler regions
• New market opportunities for heat-tolerant varieties
• Precision agriculture technologies can improve efficiency under variable rainfall

VCAA FOCUS: VCAA expects students to discuss climate change risks in the context of a specific named region. Ensure your examples are geographically specific (e.g. Victorian alpine region, Great Barrier Reef, Murray-Darling Basin) rather than generic global statements.