Coastal processes result in submersion when ocean water covers coastal areas, either temporarily during powerful storms or permanently due to rising sea levels.
Understanding Coastal Submersion
Submersion specifically refers to events where coastal regions and even islands are completely covered by ocean water. The reference explains that this can happen through different processes:
- Temporary Submersion: Often occurs during powerful storms.
- Permanent Submersion: Becoming increasingly common due to rising global sea levels.
Key Coastal Processes Leading to Submersion
Based on the reference, the two primary coastal processes causing submersion are:
Powerful Coastal Storms
During intense storms like hurricanes, a significant volume of ocean water can be pushed towards the coast. This phenomenon, known as storm surge, causes the sea level to rise dramatically and rapidly above its normal level.
- Mechanism: Strong winds and low atmospheric pressure associated with the storm lift the water surface and drive it inland.
- Outcome: Coastal areas are inundated and completely covered by ocean water.
- Duration: Typically temporary; the coast is usually exposed again above sea level once the storm passes and the surge recedes.
Rising Sea Levels
A more concerning and long-term process leading to submersion is the gradual increase in average global sea levels. This rise is primarily driven by climate change, causing thermal expansion of seawater and the melting of glaciers and ice sheets.
- Mechanism: The baseline level of the ocean steadily creeps upward over time.
- Outcome: Coastal areas situated at low elevations become progressively closer to sea level.
- Duration: Permanent; rising sea levels are causing many areas to become submerged permanently. As the sea level rises, previously dry land remains covered by water even during normal tides.
Comparing Types of Submersion
Here's a simple comparison of the two main ways coastal processes cause submersion:
| Feature | Submersion due to Storms | Submersion due to Rising Sea Levels |
|---|---|---|
| Cause | Powerful coastal storms (e.g., hurricanes), storm surge | Long-term increase in average sea level |
| Duration | Temporary | Permanent |
| Recovery | Coast returns above sea level after storm passes | Area remains covered by water |
| Primary Force | Storm-driven water surge | Gradual increase in baseline ocean volume/level |
Both processes highlight how dynamic coastal environments are and the significant impact ocean water levels can have on land. While storm-induced submersion is a recurring hazard, submersion caused by rising sea levels represents a more fundamental and lasting transformation of the coastline.
