What is mean sea level?
“Mean sea level” refers to the average height of the ocean's surface over a period of time. It is usually measured over many years to account for variations caused by tides, waves, and other short-term factors.
Global mean sea level provides an overall view of changes in sea level on a global scale and is typically calculated by combining data from satellite altimetry and global network of
tide gauges.
According to Singapore’s Third National Climate Change Study, global mean sea level is expected to rise from 0.23 to 1.15 metres (m) by 2100, or up to around 2m by 2150.
Local mean sea level, on the other hand, refers to the mean sea level at a specific location or region and is typically calculated using individual tide gauge measurements. This is also known as relative sea level.
Caption: Differences between global and local sea level. (Source: Earth Observatory of Singapore)
Global sea level offers a high-level perspective on trends in sea-level change and is valuable in comprehending global-scale phenomena like climate change.
In comparison, local sea level is more relevant for assessing the impacts of sea level change at specific coastal areas or regions.
Both factors are important for understanding the complexities of sea level dynamics and their implications for coastal communities and ecosystems.