Sea Level

Oceans
This indicator describes how sea level has changed over time.

This indicator describes how sea level has changed over time. The indicator describes two types of sea level changes: absolute and relative.

Figures

Figure 1. Global Average Absolute Sea Level Change, 1880-2023

Data source: CSIRO, 2017; NOAA, 20244,5
Web update: June 2024

Figure data (CSV) EPA source data (CSV)

This graph 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. This figure 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.) The shaded band shows the likely range of values, based on the number of measurements collected and the precision of the methods used.

Show the data behind this figure
Year CSIRO (inches) CSIRO lower bound (inches) CSIRO upper bound (inches) NOAA (inches)
1880 0.00 -0.95 0.95 NA
1881 0.22 -0.73 1.17 NA
1882 -0.44 -1.35 0.46 NA
1883 -0.23 -1.13 0.67 NA
1884 0.59 -0.28 1.46 NA
1885 0.53 -0.33 1.39 NA
1886 0.44 -0.38 1.26 NA
1887 0.22 -0.60 1.04 NA
1888 0.30 -0.52 1.12 NA
1889 0.36 -0.46 1.18 NA
1890 0.44 -0.37 1.26 NA
1891 0.37 -0.44 1.19 NA
1892 0.50 -0.31 1.31 NA
1893 0.69 -0.11 1.48 NA
1894 0.30 -0.55 1.15 NA
1895 0.77 -0.08 1.62 NA
1896 0.47 -0.37 1.30 NA
1897 0.67 -0.15 1.49 NA
1898 1.04 0.27 1.82 NA
1899 1.34 0.57 2.10 NA
1900 1.13 0.41 1.85 NA
1901 1.11 0.42 1.80 NA
1902 1.29 0.61 1.97 NA
1903 1.61 0.94 2.28 NA
1904 1.20 0.54 1.87 NA
1905 0.98 0.38 1.59 NA
1906 1.25 0.67 1.83 NA
1907 1.20 0.61 1.78 NA
1908 1.10 0.53 1.67 NA
1909 1.28 0.70 1.85 NA
1910 1.27 0.70 1.85 NA
1911 1.60 1.04 2.16 NA
1912 1.48 0.92 2.04 NA
1913 1.55 0.99 2.10 NA
1914 1.80 1.25 2.34 NA
1915 2.11 1.57 2.64 NA
1916 2.03 1.52 2.54 NA
1917 1.85 1.35 2.36 NA
1918 1.79 1.29 2.29 NA
1919 1.85 1.35 2.35 NA
1920 1.91 1.39 2.42 NA
1921 1.99 1.47 2.50 NA
1922 1.95 1.43 2.47 NA
1923 2.00 1.49 2.51 NA
1924 1.71 1.20 2.23 NA
1925 1.79 1.26 2.33 NA
1926 2.05 1.51 2.59 NA
1927 2.00 1.50 2.51 NA
1928 1.85 1.37 2.33 NA
1929 1.91 1.43 2.38 NA
1930 2.06 1.59 2.54 NA
1931 2.05 1.57 2.53 NA
1932 2.27 1.80 2.74 NA
1933 2.44 1.98 2.91 NA
1934 2.23 1.76 2.70 NA
1935 2.45 1.98 2.92 NA
1936 2.30 1.83 2.76 NA
1937 2.52 2.06 2.98 NA
1938 2.62 2.16 3.09 NA
1939 2.83 2.35 3.31 NA
1940 2.62 2.18 3.06 NA
1941 3.10 2.67 3.52 NA
1942 3.10 2.67 3.52 NA
1943 3.10 2.67 3.52 NA
1944 2.85 2.43 3.27 NA
1945 2.96 2.54 3.38 NA
1946 3.25 2.83 3.67 NA
1947 3.37 3.00 3.75 NA
1948 3.56 3.20 3.93 NA
1949 3.51 3.18 3.84 NA
1950 3.60 3.29 3.91 NA
1951 3.97 3.67 4.28 NA
1952 3.87 3.57 4.17 NA
1953 4.04 3.75 4.34 NA
1954 3.93 3.64 4.22 NA
1955 3.96 3.69 4.24 NA
1956 3.76 3.49 4.04 NA
1957 4.29 4.02 4.56 NA
1958 4.35 4.09 4.61 NA
1959 4.36 4.10 4.61 NA
1960 4.50 4.24 4.76 NA
1961 4.75 4.49 5.01 NA
1962 4.54 4.28 4.80 NA
1963 4.48 4.22 4.74 NA
1964 4.17 3.91 4.43 NA
1965 4.61 4.35 4.87 NA
1966 4.40 4.14 4.66 NA
1967 4.45 4.20 4.71 NA
1968 4.48 4.22 4.75 NA
1969 4.75 4.48 5.03 NA
1970 4.68 4.40 4.95 NA
1971 4.88 4.61 5.15 NA
1972 5.24 4.97 5.51 NA
1973 5.00 4.74 5.27 NA
1974 5.47 5.20 5.74 NA
1975 5.41 5.15 5.67 NA
1976 5.37 5.10 5.64 NA
1977 5.30 5.04 5.56 NA
1978 5.56 5.29 5.82 NA
1979 5.36 5.10 5.63 NA
1980 5.60 5.34 5.85 NA
1981 6.09 5.83 6.34 NA
1982 5.86 5.61 6.11 NA
1983 6.19 5.93 6.44 NA
1984 6.15 5.91 6.40 NA
1985 5.75 5.50 6.00 NA
1986 5.77 5.52 6.02 NA
1987 5.80 5.55 6.04 NA
1988 5.98 5.73 6.23 NA
1989 6.16 5.91 6.41 NA
1990 6.25 5.99 6.50 NA
1991 6.35 6.09 6.60 NA
1992 6.37 6.11 6.63 NA
1993 6.30 6.04 6.56 6.31
1994 6.51 6.25 6.77 6.49
1995 6.62 6.36 6.88 6.71
1996 6.78 6.52 7.04 6.85
1997 7.06 6.80 7.32 7.00
1998 6.67 6.40 6.94 6.96
1999 7.00 6.74 7.27 6.93
2000 7.06 6.79 7.32 7.09
2001 7.27 7.01 7.54 7.30
2002 7.37 7.10 7.63 7.37
2003 7.73 7.46 8.00 7.50
2004 7.71 7.44 7.98 7.57
2005 7.72 7.45 7.98 7.72
2006 7.89 7.62 8.15 7.80
2007 7.96 7.68 8.24 7.80
2008 8.30 8.04 8.57 7.96
2009 8.53 8.26 8.80 8.10
2010 8.83 8.56 9.11 8.16
2011 8.90 8.60 9.19 8.10
2012 9.24 8.92 9.57 8.49
2013 8.91 8.56 9.26 8.59
2014 NA NA NA 8.72
2015 NA NA NA 9.06
2016 NA NA NA 9.19
2017 NA NA NA 9.24
2018 NA NA NA 9.34
2019 NA NA NA 9.59
2020 NA NA NA 9.70
2021 NA NA NA 9.89
2022 NA NA NA 9.97
2023 NA NA NA 10.20

Figure 2. Relative Sea Level Change Along U.S. Coasts, 1960-2023

Data source: NOAA, 20246
Web update: June 2024

Figure data (CSV) EPA source data (CSV)

This map shows cumulative changes in relative sea level from 1960 to 2023 at tide gauge stations along U.S. coasts. Relative sea level reflects changes in sea level as well as land elevation.

EPA draws this figure as a map of the 72 tide gauge stations. The stations stretch from Kwajalein in the Marshall Islands to Bermuda and cluster tightly along the Mid-Atlantic coast, so each station is drawn here as one row on the change axis, read from the largest rise at the top to the largest fall at the bottom. Every station EPA maps is on the chart.

Show the data behind this figure
Station State Latitude Longitude Relative sea level change, 1960–2023 (inches)
Grand Isle Louisiana 29.2633°N 89.9567°W 22.72
Galveston Bay Entrance Texas 29.3575°N 94.7247°W 16.27
Rockport Texas 28.0217°N 97.0467°W 14.86
Texas Point Texas 29.6893°N 93.8418°W 14.34
Yorktown Virginia 37.2265°N 76.4788°W 11.93
Sewells Point Virginia 36.9428°N 76.3286°W 11.88
Port Isabel Texas 26.0612°N 97.2155°W 10.71
Sandy Hook New Jersey 40.4669°N 74.0094°W 10.49
Atlantic City New Jersey 39.3567°N 74.4181°W 10.44
South Padre Island Texas 26.0731°N 97.1675°W 10.34
Solomons Island Maryland 38.3172°N 76.4508°W 10.02
Cambridge Maryland 38.5725°N 76.0617°W 9.85
Kiptopeke Virginia 37.1652°N 75.9884°W 9.80
Reedy Point Delaware 39.5583°N 75.5719°W 9.65
Annapolis Maryland 38.9833°N 76.4816°W 9.43
Lewes Delaware 38.7828°N 75.1193°W 9.20
Freeport Harbor Texas 28.9357°N 95.2942°W 8.95
Fort Pulaski Georgia 32.0347°N 80.903°W 8.95
Beaufort North Carolina 34.7173°N 76.6707°W 8.81
Montauk New York 41.0483°N 71.9594°W 8.76
Washington D. C. 38.8733°N 77.0217°W 8.66
Charleston South Carolina 32.7808°N 79.9236°W 8.63
Springmaid Pier South Carolina 33.6556°N 78.9164°W 8.16
Baltimore Maryland 39.2667°N 76.5783°W 8.11
Virginia Key Florida 25.7314°N 80.1618°W 7.84
Philadelphia Pennsylvania 39.9331°N 75.142°W 7.71
Hilo Hawaii 19.7303°N 155.056°W 7.71
St. Petersburg Florida 27.7611°N 82.6269°W 7.66
Woods Hole Massachusetts 41.5236°N 70.6711°W 7.61
Boston Massachusetts 42.3539°N 71.0503°W 7.29
The Battery New York 40.7006°N 74.0142°W 7.24
Newport Rhode Island 41.5043°N 71.3261°W 7.24
Mayport Florida 30.3982°N 81.4279°W 7.17
New London Connecticut 41.3614°N 72.09°W 7.12
Wilmington North Carolina 34.2275°N 77.9536°W 6.77
Pensacola Florida 30.4044°N 87.2112°W 6.67
Kings Point New York 40.8103°N 73.7649°W 6.62
Key West Florida 24.5557°N 81.8079°W 6.47
Providence Rhode Island 41.8072°N 71.4007°W 6.35
Bar Harbor Maine 44.3922°N 68.2043°W 5.95
Cedar Key Florida 29.135°N 83.0317°W 5.83
Fernandina Beach Florida 30.6714°N 81.4658°W 5.66
Eastport Maine 44.9046°N 66.9829°W 5.66
Biological Station Bermuda 32.37°N 64.695°W 5.61
San Diego California 32.7156°N 117.177°W 5.53
Kahului Hawaii 20.8949°N 156.469°W 5.48
Seavey Island Maine 43.0797°N 70.7411°W 5.38
Seattle Washington 47.6026°N 122.339°W 5.16
Wake Island Pacific Ocean 19.2906°N 166.6175°E 5.13
Kwajalein Marshall Islands 8.7317°N 167.7361°E 5.11
La Jolla California 32.8669°N 117.257°W 5.08
Magueyes Island Puerto Rico 17.9701°N 67.0464°W 4.99
San Francisco California 37.8063°N 122.466°W 4.94
Portland Maine 43.6581°N 70.2442°W 4.84
Nawiliwili Hawaii 21.9544°N 159.356°W 4.44
Mokuoloe Hawaii 21.4331°N 157.79°W 4.12
Midway Atoll Pacific Ocean 28.2117°N 177.36°W 3.87
Santa Monica California 34.0083°N 118.5°W 3.84
Honolulu Hawaii 21.3033°N 157.865°W 3.82
Friday Harbor Washington 48.5453°N 123.013°W 2.95
Los Angeles California 33.7199°N 118.273°W 2.65
Port San Luis California 35.1767°N 120.76°W 2.51
Alameda California 37.772°N 122.3°W 2.28
Astoria Oregon 46.2073°N 123.768°W -0.35
Ketchikan Alaska 55.3319°N 131.626°W -0.89
Crescent City California 41.7456°N 124.184°W -1.93
Neah Bay Washington 48.3707°N 124.602°W -4.24
Adak Island Alaska 51.8606°N 176.638°W -6.00
Sitka Alaska 57.0517°N 135.342°W -6.08
Unalaska Alaska 53.8792°N 166.54°W -10.62
Juneau Alaska 58.2988°N 134.411°W -33.31
Skagway Alaska 59.4508°N 135.328°W -44.74

Key Points

  • After a period of approximately 2,000 years of little change (not shown here), global average sea level rose throughout the 20th century, and the rate of change has accelerated in recent years.2 When averaged over all of the world’s oceans, absolute sea level rose at an average rate of 0.06 inches per year from 1880 to 2013 (Figure 1). Since 1993, however, average sea level rose at a rate of 0.12 inches per year—roughly twice as fast as the long-term trend.
  • Relative sea level rose along much of the U.S. coastline between 1960 and 2023, particularly the Mid-Atlantic coast and parts of the Gulf coast, where some stations recorded increases of more than 8 inches (Figure 2). Meanwhile, relative sea level fell at some locations in Alaska and the Pacific Northwest. At those sites, even though absolute sea level has risen, land elevation has risen more rapidly.
  • While absolute sea level has increased steadily overall, particularly in recent decades, regional trends vary, and absolute sea level has decreased in some places.3 Relative sea level also has not risen uniformly because of regional and local changes in land movement and long-term changes in coastal circulation patterns.

Background

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 (see the Glaciers indicator).
  2. As water warms, it expands slightly—an effect that is cumulative over the entire depth of the oceans (see the Ocean Heat indicator).

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.

Scientists account for these types of changes by measuring sea level change in two different ways. Relative sea level change refers to how the height of the ocean rises or falls relative to the land at a particular location. In contrast, absolute sea level change refers to the height of the ocean surface above the center of the earth, without regard to whether nearby land is rising or falling. Evidence suggests sea level along the U.S. coastline will rise 10 to 12 inches by 2050—as much as the rise measured from 1920 to 2020.1 (The 10 to 12 inches are an average: differences in both land and ocean height mean the rise will vary regionally along U.S. coasts.)

About the Indicator

This indicator presents trends in sea level based on measurements from tide gauges and from satellites that orbit the Earth. Tide gauges measure relative sea level change at points along the coast, while satellite instruments measure absolute sea level change over nearly the entire ocean surface. Many tide gauges have collected data for more than 100 years, while satellites have collected data since the early 1990s.

Figure 1 shows annual absolute sea level change averaged over the entire Earth’s ocean surface. The long-term trend is based on tide gauge data that have been adjusted to show absolute global trends through calibration with recent satellite data. This long-term data set has been calculated through 2013, while satellite data are now available through the end of 2023. Figure 2 shows trends at a more local scale, highlighting the 1960 to 2023 change in relative sea level at 72 tide gauges along the Atlantic, Pacific, and Gulf coasts of the United States.

Indicator Notes

Relative sea level trends represent a combination of absolute sea level change and any local land movement. Tide gauge measurements such as those in Figure 2 generally cannot distinguish between these two different influences without an accurate measurement of vertical land motion nearby.

Some changes in relative and absolute sea level can be due to multi-year cycles such as El Niño and La Niña, which affect coastal ocean temperatures, salt content, wind patterns, atmospheric pressure (and thus storm tracks), and currents. Obtaining a reliable trend can require many years of data, which is why the satellite record in Figure 1 has been supplemented with a longer-term reconstruction based on tide gauge measurements.

Data Sources

Absolute sea level trends were provided by Australia’s Commonwealth Scientific and Industrial Research Organisation and the National Oceanic and Atmospheric Administration. These data are based on measurements collected by satellites and tide gauges. Relative sea level data are available from the National Oceanic and Atmospheric Administration, which publishes an interactive online map (https://tidesandcurrents.noaa.gov/sltrends/sltrends.html) with links to detailed data for each tide gauge.

Technical Documentation

References

  1. Sweet, W. V., Hamlington, B. D., Kopp, R. E., Weaver, C. P., Barnard, P. L., Bekaert, D., Brooks, W., Craghan, M., Dusek, G., Frederikse, T., Garner, G., Genz, A. S., Krasting, J. P., Larour, E., Marcy, D., Marra, J. J., Obeysekera, J., Osler, M., Pendleton, M., … Zuzak, C. (2022). Global and regional sea level rise scenarios for the United States: Updated mean projections and extreme water level probabilities along U.S. coastlines (NOAA Technical Report NOS 01). National Oceanic and Atmospheric Administration. https://oceanservice.noaa.gov/hazards/sealevelrise/sealevelrise-tech-report.html
  2. Sweet, W. V., Horton, R., Kopp, R. E., LeGrande, A. N., & Romanou, A. (2017). Chapter 12: Sea level rise. In USGCRP (U.S. Global Change Research Program), Climate science special report: Fourth National Climate Assessment, volume I (pp. 333–363). https://doi.org/10.7930/J0VM49F2
  3. Sea Level Research Group. (2024). Trend map. Retrieved May 17, 2024, from https://sealevel.colorado.edu/trend-map
  4. CSIRO (Commonwealth Scientific and Industrial Research Organisation). (2017). Update to data originally published in: Church, J. A., & White, N. J. (2011). Sea-level rise from the late 19th to the early 21st century. Surveys in Geophysics, 32, 585–602. www.cmar.csiro.au/sealevel/sl_data_cmar.html
  5. NOAA (National Oceanic and Atmospheric Administration). (2024). Laboratory for Satellite Altimetry: Sea level rise. Retrieved March 1, 2024, from www.star.nesdis.noaa.gov/sod/lsa/SeaLevelRise/LSA_SLR_timeseries_global.php
  6. NOAA (National Oceanic and Atmospheric Administration). (2024). Update to data originally published in: NOAA. (2009). Sea level variations of the United States 1854–2006 (NOAA Technical Report NOS CO-OPS 053). www.tidesandcurrents.noaa.gov/publications/Tech_rpt_53.pdf

Text on this page is EPA’s own published wording (a U.S. Government work, not subject to domestic copyright), extracted from EPA’s published indicator page and verified paragraph by paragraph against the archived HTML. Data, chart code, and the full extraction pipeline are maintained in the sea-level repository, which this page reads its data from directly.

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