Sea Level Rise
Sea level rise (SLR) is the increase in the volume of the global ocean, leading to higher surface levels relative to land. Driven primarily by thermal expansion of seawater as it warms and the melting of land-based ice (glaciers and ice sheets), SLR poses critical risks to coastal infrastructure, ecosystems, and human settlements.
Mechanisms
- Thermal Expansion: As ocean temperatures rise due to Global Warming, water molecules gain energy and spread apart.
- Cryosphere Melt: Disintegration of Greenland Ice Sheet and Antarctic Ice Sheet, along with global glacier retreat, adds freshwater mass to the oceans.
- Land Subsidence: Localized sinking of land due to groundwater extraction or sediment compaction exacerbates relative sea level rise.
Impacts & Adaptation
- Coastal Flooding: Increased frequency of nuisance flooding and catastrophic storm surge events.
- Saltwater Intrusion: Contamination of freshwater aquifers and agricultural soils.
- Ecosystem Loss: Degradation of Mangroves, wetlands, and coral reefs.
- Migration: Displacement of populations in low-lying island nations and coastal deltas.
Case Study: Port Phillip Bay
The dynamics of SLR are critical in understanding the geological and resource history of enclosed bays like Port Phillip Bay. As water levels fluctuate over geological timescales, they expose or submerge significant mineral deposits. Recent analysis highlights the potential for recovering submerged resources in these areas.
- See Port Phillip Bay & Melbourne: Submerged and Buried Gold Potential Report for detailed geological assessment regarding gold deposits beneath the bay and Melbourne, which may be accessed or exposed through changes in bay morphology and sediment levels.