Sea level rise and sea level variability are two related but distinct phenomena that affect the level of the world’s oceans. Here’s a brief explanation of each:
Sea level rise: Sea level rise refers to the long-term increase in the average level of the world’s oceans. This rise is primarily caused by two factors: the thermal expansion of seawater as it warms and the melting of glaciers and ice caps on land, which adds water to the oceans. According to the Intergovernmental Panel on Climate Change (IPCC), sea levels have risen by about 15 cm (6 inches) since the late 19th century, and are projected to rise by between 26 and 82 cm (10 to 32 inches) by the end of the 21st century, depending on future greenhouse gas emissions.
Sea level variability: Sea level variability refers to the shorter-term changes in the level of the world’s oceans that occur due to a range of factors, including tides, storm surges, and ocean currents. Sea level variability can occur over timescales ranging from hours to decades, and can have significant impacts on coastal areas, including flooding and erosion.
While sea level rise and sea level variability are distinct phenomena, they are closely related, as sea level rise can exacerbate the impacts of sea level variability on coastal areas. For example, as sea levels rise, storm surges and high tides can cause more frequent and severe flooding in low-lying coastal areas, leading to erosion and other forms of damage.
Understanding sea level rise and sea level variability is important for developing strategies to mitigate their impacts on coastal communities and infrastructure. This includes measures such as coastal protection and adaptation, as well as efforts to reduce greenhouse gas emissions and limit the long-term impacts of sea level rise.
Impacts of sea level rise: As sea levels continue to rise, the impacts on coastal areas are becoming increasingly severe. This includes increased flooding and erosion, loss of habitats, and damage to infrastructure such as buildings, roads, and bridges. The impacts of sea level rise are particularly significant in low-lying areas, including many small island nations, where even small increases in sea level can have devastating consequences.
Causes of sea level variability: Sea level variability can be caused by a range of factors, including tides, waves, and ocean currents. For example, ocean currents such as the Gulf Stream can cause sea levels to rise along the eastern coast of the United States, while tides and storm surges can cause short-term increases in sea level in coastal areas.
Monitoring sea level: To understand and respond to sea level rise and sea level variability, it is important to have accurate and reliable data on sea level changes. This includes data from tide gauges and satellite measurements, which are used to monitor sea level changes over time and to identify trends and patterns.
Mitigating the impacts: There are a range of strategies that can be used to mitigate the impacts of sea level rise and sea level variability. These include coastal protection measures such as sea walls and beach nourishment, as well as land-use planning and other measures to reduce the vulnerability of coastal communities and infrastructure. Additionally, efforts to reduce greenhouse gas emissions and limit the long-term impacts of climate change are also important for addressing sea level rise.
In summary, sea level rise and sea level variability are two related but distinct phenomena that affect the level of the world’s oceans. While sea level rise is primarily caused by long-term changes in the climate system, sea level variability can be caused by a range of shorter-term factors. Understanding these phenomena and their impacts is important for developing strategies to mitigate the impacts on coastal communities and infrastructure.