Sea level rise

Definition

Sea level rise refers to the increasing average level of the world's oceans due to various factors, including thermal expansion of seawater as it warms and the melting of glaciers and ice sheets. This phenomenon is closely linked to climate change, as rising global temperatures contribute to these processes, affecting coastal ecosystems, human settlements, and geomorphic systems globally.

5 Must Know Facts For Your Next Test

1. Global sea levels have risen by approximately 8-9 inches since 1880, with a significant acceleration observed in recent decades.
2. Melting polar ice sheets and glaciers contribute over half of the current rate of sea level rise, with projections indicating that this could increase substantially if global warming continues.
3. Rising sea levels threaten low-lying coastal areas, leading to increased flooding, loss of habitat, and displacement of communities.
4. Climate change has also intensified storm surges, making coastal areas more vulnerable to flooding during extreme weather events.
5. Some regions experience different rates of sea level rise due to factors like ocean currents, land subsidence, and geological activity.

Review Questions

• How does thermal expansion of seawater contribute to sea level rise?
  • Thermal expansion occurs when water warms up and takes up more space. As global temperatures increase due to climate change, the oceans absorb heat, causing seawater to expand. This process is a significant contributor to sea level rise, accounting for nearly half of the observed increase in sea levels since the late 19th century. Understanding thermal expansion is crucial for predicting future sea level trends and impacts.
• Discuss the implications of sea level rise on coastal geomorphic systems and human settlements.
  • Sea level rise significantly impacts coastal geomorphic systems by altering sediment transport, increasing erosion rates, and transforming landforms. Human settlements in low-lying coastal areas face risks such as flooding and saltwater intrusion into freshwater supplies. As sea levels continue to rise, cities may need to implement adaptive measures like constructing seawalls or investing in managed retreat strategies to protect infrastructure and communities from the encroaching ocean.
• Evaluate the potential future scenarios for sea level rise based on current climate models and their broader environmental consequences.
  • Current climate models project that sea levels could rise anywhere from 1 to over 6 feet by the end of the century if greenhouse gas emissions continue at current rates. This scenario poses severe environmental consequences, including widespread habitat loss for both terrestrial and marine species, increased salinity in estuaries affecting local ecosystems, and heightened vulnerability of coastal populations. The potential for rapid changes underscores the urgency for effective climate policies aimed at mitigation and adaptation strategies.

Related terms

Thermal expansion: The process by which water expands as it warms, contributing to sea level rise.

Glacial melt: The melting of glaciers and ice sheets, primarily in Greenland and Antarctica, which adds freshwater to the oceans and raises sea levels.

Coastal erosion: The wearing away of land along the coastline, which can be accelerated by rising sea levels and increased storm intensity.