Global Average Absolute Sea Level Change

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This dataset shows cumulative changes in sea level for the world’s oceans since 1880, based on a combination of long-term tide gauge measurements and recent satellite measurements. It also shows average absolute sea level change, which refers to the height of the ocean surface, regardless of whether nearby land is rising or falling. Satellite data are based solely on measured sea level, while the long-term tide gauge data include a small correction factor because the size and shape of the oceans are changing slowly over time. On average, the ocean floor has been gradually sinking since the last Ice Age peak, 20,000 years ago.

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As the temperature of the Earth changes, so does sea level. Temperature and sea level are linked for two main reasons: 1. Changes in the volume of water and ice on land (namely glaciers and ice sheets) can increase or decrease the volume of water in the ocean, and 2. As water warms, it expands slightly—an effect that is cumulative over the entire depth of the oceans.

Changing sea levels can affect human activities in coastal areas. Rising sea level inundates low-lying wetlands and dry land, erodes shorelines, contributes to coastal flooding, and increases the flow of salt water into estuaries and nearby groundwater aquifers. Higher sea level also makes coastal infrastructure more vulnerable to damage from storms.

The sea level changes that affect coastal systems involve more than just expanding oceans, however, because the Earth’s continents can also rise and fall relative to the oceans. Land can rise through processes such as sediment accumulation (the process that built the Mississippi River delta) and geological uplift (for example, as glaciers melt and the land below is no longer weighed down by heavy ice). In other areas, land can sink because of erosion, sediment compaction, natural subsidence (sinking due to geologic changes), groundwater withdrawal, or engineering projects that prevent rivers from naturally depositing sediments along their banks. Changes in ocean currents such as the Gulf Stream can also affect sea levels by pushing more water against some coastlines and pulling it away from others, raising or lowering sea levels accordingly.

After a period of approximately 2,000 years of little change, global average sea level rose throughout the 20th century, and the rate of change has accelerated in recent years. When averaged over all of the world’s oceans, absolute sea level has risen at an average rate of 0.06 inches per year from 1880 to 2013. Since 1993, however, average sea level has risen at a rate of 0.11 to 0.14 inches per year—roughly twice as fast as the long-term trend.

Date Created

2016

Last Modified

2016-08

Version

2016-08

Update Frequency

Annual

Temporal Coverage

1880-2015

Spatial Coverage

World

Source

John Snow Labs => Commonwealth Scientific and Industrial Research Organisation (CSIRO), National Oceanic and Atmospheric Administration (NOAA)

Source License URL

John Snow Labs Standard License

Source License Requirements

N/A

Source Citation

N/A

Keywords

Sea Level, Climate Change, Absolute Sea Level Change, Global Average Sea Level, Ocean Levels, Environment

Other Titles

Average Absolute Sea Level Change Worldwide, Average Cumulative Changes in Sea Level

NameDescriptionTypeConstraints
Measurement_YearYear of measurementdaterequired : 1
CSIRO_Adjusted_Sea_LevelCSIRO (Commonwealth Scientific and Industrial Research Organisation) adjusted sea level changes are the comulative changes (in inches) in sea level for the world’s oceans based on the combination of long-term tide gauge measurements and recent satellite measurements.numberlevel : Ratio
Lower_Error_BoundLower error bound sea level changes measured in inchesnumberlevel : Ratio
Upper_Error_BoundUpper error bound sea level changes measured in inchesnumberlevel : Ratio
NOAA_Adjusted_Sea_LevelNOAA (National Oceanic and Atmospheric Administration) adjusted sea level changes are the comulative changes (in inches) in sea levelnumberlevel : Ratio
Measurement_YearCSIRO_Adjusted_Sea_LevelLower_Error_BoundUpper_Error_BoundNOAA_Adjusted_Sea_Level
20148.598323546
20158.943307703
1880-0.9527559050.952755905
18981.0433070860.2677165351.818897636
18991.3385826760.5748031492.102362203
19001.1259842510.4055118111.846456691
19011.1102362190.4173228341.803149604
19021.2913385810.6102362201.972440943
19031.6062992110.9370078732.275590549
19041.2007874000.5354330701.866141730