Absolute sea level rise

Definition

Absolute sea level rise refers to the increase in the overall height of the ocean surface measured relative to a fixed point on land. This phenomenon is primarily caused by two key factors: thermal expansion of seawater as it warms and the addition of water from melting ice sheets and glaciers. Understanding absolute sea level rise is essential for assessing regional variations, as different areas experience varying rates due to factors like land subsidence, ocean currents, and local climate conditions.

5 Must Know Facts For Your Next Test

1. Global average absolute sea level has risen about 8-9 inches since the late 19th century, with projections suggesting further increases in the future.
2. Regions experiencing significant glacial melt, such as Greenland and Antarctica, are contributing disproportionately to absolute sea level rise compared to areas with stable ice.
3. Local geological processes, like subsidence or uplift, can significantly affect how much absolute sea level rise is felt in different coastal areas.
4. Thermal expansion accounts for roughly half of the observed sea level rise, highlighting the importance of ocean warming in this phenomenon.
5. Satellite altimetry has become a crucial tool for measuring absolute sea level rise, providing accurate data on global ocean heights over time.

Review Questions

• What are the primary causes of absolute sea level rise and how do they differ from relative sea level changes?
  • The primary causes of absolute sea level rise are thermal expansion of seawater due to warming and glacial melt from ice sheets and glaciers. In contrast, relative sea level changes include local factors such as land subsidence or uplift that can cause variations in sea level experienced at a specific location. While absolute sea level rise refers to a global measurement, relative changes consider localized influences that can either amplify or mitigate the effects of global trends.
• How do regional variations in absolute sea level rise impact coastal communities differently around the world?
  • Regional variations in absolute sea level rise can lead to unequal impacts on coastal communities based on local conditions. For example, areas experiencing significant land subsidence may face more severe flooding risks than regions with stable land. Additionally, places heavily reliant on glacial melt may see rapid changes in their coastlines compared to others. Understanding these differences is crucial for developing targeted adaptation strategies that address each community's unique vulnerabilities and needs.
• Evaluate the long-term implications of continuous absolute sea level rise on ecosystems and human infrastructure.
  • Continuous absolute sea level rise poses significant long-term implications for both ecosystems and human infrastructure. Ecosystems such as coastal wetlands and mangroves face threats from increased salinity and habitat loss, which can disrupt biodiversity. For human infrastructure, rising seas can lead to increased flooding and erosion, impacting roads, homes, and critical facilities. As populations grow in coastal areas, planning for resilience against these ongoing changes will be vital for sustainable development and disaster preparedness.

Related terms

thermal expansion: The increase in volume of seawater as it warms, contributing to rising sea levels.

glacial melt: The process of glaciers and ice sheets losing mass due to warming temperatures, adding freshwater to the oceans.

relative sea level rise: The change in sea level experienced at a specific location, which can differ from absolute sea level rise due to local land movement and other factors.