Sea level change refer to the rise or fall in the average level of the ocean surface relative to the land over time. This phenomenon is caused by a combination of factors, including the thermal expansion of seawater, the melting of ice sheets and glaciers, and changes in ocean currents and weather patterns.
Over the past century, global sea levels have risen by approximately 20 cm (8 inches), and the rate of rise has increased in recent decades. This is largely due to the warming of the planet, which causes the thermal expansion of seawater and the melting of ice sheets and glaciers. As a result, coastal areas are at risk of flooding, and low-lying islands and coastal communities are particularly vulnerable to the impacts of sea level rise.
In addition to the impacts on human populations, sea level changes can also have significant ecological impacts. For example, rising sea levels can lead to the loss of coastal wetlands, which provide important habitats for a variety of plant and animal species. They can also lead to the erosion of beaches and coastal cliffs, which can threaten the stability of buildings and infrastructure.
Overall, sea level changes are an important aspect of global climate change, and efforts to mitigate and adapt to these changes are critical for the long-term sustainability of human populations and the natural environment.
Causes of Sea level change
Sea level changes are caused by a variety of natural and human factors. Some of the main causes of sea level changes include:
- Thermal expansion of seawater: As the planet warms, seawater expands and takes up more space, causing sea levels to rise.
- Melting of glaciers and ice caps: Melting of glaciers and ice caps can add water to the oceans, contributing to sea level rise.
- Melting of ice sheets: The melting of ice sheets in Greenland and Antarctica is a major contributor to sea level rise. These ice sheets hold vast amounts of water and, as they melt, they can cause significant increases in sea levels.
- Changes in ocean currents: Changes in ocean currents can cause sea levels to rise or fall in different regions of the world.
- Land subsidence: In some regions, land is subsiding, or sinking, which can cause sea levels to appear to rise even if the water level is unchanged.
- Human activities: Human activities such as groundwater pumping and the construction of large dams can cause land subsidence, which in turn can contribute to sea level rise. In addition, the burning of fossil fuels and the release of greenhouse gases into the atmosphere contribute to global warming, which is a major driver of sea level rise.
It is important to note that sea level changes are a complex and dynamic process, and understanding the factors that contribute to these changes is essential for developing effective strategies to mitigate and adapt to their impacts.