Imagine our planet sipping from the oceans, causing sea levels to creep up over a century, but new data reveals that gentle sip has turned into a concerning gulp.
Key Takeaways
- Global mean sea level rose by 1.7 mm per year from 1900 to 2018, totaling approximately 21-24 cm since 1880 with acceleration in recent decades.
- U.S. coastal sea levels have risen by 23 cm (9 inches) since 1880, faster than the global average due to land subsidence.
- Tide gauge records from 1901-2010 show a global sea level rise of 19 cm (7.5 inches).
- Global mean sea level rose 3.7 mm/yr from 2006-2015, the highest decadal rate on record.
- Satellite altimetry shows 4.3 mm/yr rise in 2020.
- NOAA tide gauges report U.S. average 3.8 mm/yr 2010-2020.
- Global mean sea level to rise 0.28-0.55 m by 2100 under SSP1-2.6 (low emissions).
- Under SSP5-8.5 (high emissions), global SLR projected at 0.63-1.01 m by 2100.
- U.S. East Coast projected 0.3-0.8 m by 2050 relative to 2000.
- Global mean sea level rise primarily driven by ocean thermal expansion (42%) and glacier melt (21%) since 1971.
- Greenland Ice Sheet mass loss averaged 169 Gt/yr 1992-2020, contributing 21% to SLR.
- Antarctic Ice Sheet contributed 7.4 mm to SLR 1992-2017 via 2520 Gt loss.
- U.S. East Coast experiences 3-4 times global average SLR due to AMOC slowdown.
- Gulf of Mexico relative SLR 2x global due to subsidence.
- Western Pacific Warm Pool sees 12 cm/decade rise.
Sea levels are rising globally at an accelerating pace.
Causes and Contributing Factors
1Global mean sea level rise primarily driven by ocean thermal expansion (42%) and glacier melt (21%) since 1971.
Verified2Greenland Ice Sheet mass loss averaged 169 Gt/yr 1992-2020, contributing 21% to SLR.
Verified3Antarctic Ice Sheet contributed 7.4 mm to SLR 1992-2017 via 2520 Gt loss.
Verified4Glaciers outside Greenland/Antarctica lost 227 Gt/yr 2000-2019, 48% of SLR.
Directional5Terrestrial water storage change net -76 Gt/yr 1993-2018, subtracting 0.4 mm SLR.
Single source6Ocean warming caused 50% of 20th century SLR via thermal expansion.
Verified7Thwaites Glacier instability from warm ocean water, potential 65 cm SLR.
Verified8Groundwater depletion contributes 1.2 mm/yr to SLR.
Verified9Mountain glacier retreat accelerated by 47% since 2000.
Directional10Pine Island Glacier buttressing loss from ice shelf melt.
Single source11Ocean heat uptake increased 91% since pre-industrial, driving expansion.
Verified12Coriolis effect amplifies SLR in western ocean basins.
Verified13Land subsidence from oil/gas extraction adds 25% to relative SLR in Gulf.
Verified14Warming-induced ice sheet dynamical instability multiplies SLR 2-5x.
Directional15Reservoir impoundment slowed SLR by 0.8 mm since 1960.
Single source16Methane hydrate destabilization potential minor <0.5% SLR.
Verified17Sediment compaction in deltas causes 1-10 mm/yr subsidence.
Verified18Basal ice shelf melting from Circumpolar Deep Water intrusion.
Verified19Urbanization-induced subsidence 2-15 mm/yr in coastal cities.
Directional20Steric SLR from salinity changes <10% of total.
Single source21Global glacier mass balance -390 Gt/yr 2012-2019.
Verified22Greenland surface melt 464 Gt/yr average 2010-2019.
Verified23Antarctic surface mass balance +105 Gt/yr offset by discharge.
Verified24Western Antarctic ice sheet vulnerable to marine ice sheet instability.
Directional25Global land ice loss 387 Gt/yr 2015-2019.
Single source26Ocean acidification indirectly affects by altering ecosystems but minor direct SLR.
VerifiedCauses and Contributing Factors Interpretation
If I had to summarize, I'd say our oceans are rising like a bad stock market graph, driven by a feverish cocktail of expanding warm water and retreating ice, with humanity actively adding its own reckless investments of groundwater pumping and land subsidence to the portfolio.
Current Measurements
1Global mean sea level rose 3.7 mm/yr from 2006-2015, the highest decadal rate on record.
Verified2Satellite altimetry shows 4.3 mm/yr rise in 2020.
Verified3NOAA tide gauges report U.S. average 3.8 mm/yr 2010-2020.
Verified4Global steric rise 2.0 mm/yr 2015-2020 from Argo floats.
Directional5Greenland ice melt contributed 0.8 mm/yr to sea level 2012-2020.
Single source6Antarctic ice sheet loss 150 Gt/yr 2012-2017, equating to 0.4 mm/yr SLR.
Verified7Western Pacific current rate 5.1 mm/yr.
Verified8U.S. Gulf Coast 7-10 mm/yr due to subsidence and SLR.
Verified9Miami tide gauge 8 mm/yr 2006-2015.
Directional10Norfolk, VA 4.8 mm/yr 1975-2020.
Single source11Shanghai current rate 3.9 mm/yr 1980-2020.
Verified12Bangladesh coast 7.1 mm/yr 2000-2015.
Verified13Venice Lagoon 3.4 mm/yr 1993-2018.
Verified14Pacific Northwest 2.9 mm/yr 1990-2020.
Directional15Arctic Ocean 3.9 mm/yr 2003-2018 from Envisat.
Single source16Indian Ocean average 4.0 mm/yr 2010-2020.
Verified17Mediterranean 3.7 mm/yr 1993-2019.
Verified18Global ocean heat content rise implies 1.5 mm/yr thermal expansion 2015-2020.
Verified19GRACE-FO shows land water storage contributing -0.2 mm/yr net 2018-2020.
Directional20Southeast U.S. 5.2 mm/yr 2015-2020.
Single source21Australia east coast 5.5 mm/yr 2010-2020.
Verified22Japan current 4.2 mm/yr 2005-2020.
Verified23Maldives 5.8 mm/yr 2000-2020.
Verified24Louisiana coast 9.8 mm/yr 2008-2018.
DirectionalCurrent Measurements Interpretation
The sea is no longer politely knocking at our door; it's now kicking it in with regional and accelerating urgency, from Louisiana's drastic retreat to the Maldives' creeping reality, all while the planet-wide fever of thermal expansion and ice melt keeps pouring more water into the bathtub.
Future Projections
1Global mean sea level to rise 0.28-0.55 m by 2100 under SSP1-2.6 (low emissions).
Verified2Under SSP5-8.5 (high emissions), global SLR projected at 0.63-1.01 m by 2100.
Verified3U.S. East Coast projected 0.3-0.8 m by 2050 relative to 2000.
Verified4Global mean SLR 0.43 m (likely range 0.29–0.59 m) by 2100 for RCP4.5.
Directional5Antarctic instability could add 0.5-2.3 m by 2300 under high emissions.
Single source6Thermal expansion to contribute 30-50% of SLR by 2100.
Verified7Greenland meltwater projected 0.09 m by 2100 under RCP8.5.
Verified8Miami projected 0.5-1.2 m by 2060.
Verified9Global SLR acceleration to 8-10 mm/yr by 2060 under medium emissions.
Directional10Pacific islands 0.2-0.4 m by 2050.
Single source11Europe coasts 0.3-0.9 m by 2100.
Verified12Bangladesh Delta 0.3-0.6 m by 2050, displacing millions.
Verified13Shanghai 0.4-0.8 m by 2100 with subsidence.
Verified14Arctic summer sea ice loss amplifying 0.1-0.3 m extra SLR by 2100.
Directional15Low-lying atolls risk submersion with 0.5 m SLR by 2100.
Single source16U.S. West Coast 0.2-0.5 m by 2050.
Verified17Global 5-10% exceedance probability SLR 2 m by 2100 under high emissions.
Verified182.5 m SLR by 2300 possible with unmitigated warming.
Verified19Venice projected 0.5-1.0 m by 2100.
Directional20Global mean 1.0 m by 2300 under SSP2-4.5.
Single source21Norfolk VA 0.6-1.5 m by 2100.
Verified22New York City 0.4-0.8 m by 2050.
Verified23Southeast Florida 1.0-2.0 m by 2100 high scenario.
Verified24Louisiana 0.5-2.0 m by 2100 with subsidence.
Directional25Global SLR 0.1 m/decade by 2100 under RCP2.6.
Single source26U.S. East Coast relative SLR 20-30 cm/decade by 2050 in hotspots.
Verified27Kiribati atolls 0.3-0.5 m by 2050.
VerifiedFuture Projections Interpretation
To comprehend these numbers is to realize that Mother Nature's ledger book is now open, and she is presenting a bill for our carbon party, payable not by us, but by our children, in drowned cities and lost homelands.
Historical Observations
1Global mean sea level rose by 1.7 mm per year from 1900 to 2018, totaling approximately 21-24 cm since 1880 with acceleration in recent decades.
Verified2U.S. coastal sea levels have risen by 23 cm (9 inches) since 1880, faster than the global average due to land subsidence.
Verified3Tide gauge records from 1901-2010 show a global sea level rise of 19 cm (7.5 inches).
Verified4Satellite altimetry data from 1993-2018 indicates 3.7 mm/yr rise, contributing 5.4 cm total.
Directional5European tide gauges record 1.5 mm/yr average rise from 1900-2000.
Single source6Australian sea levels rose 8.7 cm from 1966-2009 at 1.6 mm/yr.
Verified7Pacific islands tide data shows 1.8 mm/yr from 1993-2012.
Verified8Gulf of Mexico historical rise of 2.4 mm/yr since 1900 due to subsidence.
Verified9Baltic Sea levels rose 1.2 mm/yr from 1880-2010.
Directional10Mediterranean Sea historical rise of 1.2 mm/yr 1900-2000.
Single source11Arctic Ocean sea level rose 2.2 mm/yr 1992-2014 from GRACE data.
Verified12Indian Ocean tide gauges show 1.9 mm/yr since 1960.
Verified13Antarctic Peninsula sea level rise of 2.5 mm/yr 1992-2017.
Verified14Global steric sea level rise from thermal expansion 1901-2010 was 0.4 mm/yr.
Directional15U.S. East Coast historical rise 3.2 mm/yr 1927-2009.
Single source16Japan tide records 2.8 cm/decade since 1950.
Verified17China coast 3.3 mm/yr 1980-2010.
Verified18Netherlands sea level rise 1.8 mm/yr 1890-2015.
Verified19Florida historical rise 2.0 mm/yr since 1930.
Directional20Hawaii islands 1.5 mm/yr 1905-2015.
Single source21Global mean sea level acceleration detected at 0.08 mm/yr² from 1900-2000.
Verified2220th century total rise 17 cm with 60% from thermal expansion.
Verified23Tide gauges worldwide show 1.8 ± 0.3 mm/yr 1901-2018.
Verified24Post-1993 satellite rise 3.3 ± 0.4 mm/yr to 2020.
Directional25Southeast Asia 3.6 mm/yr 1993-2017.
Single source26North Atlantic historical 1.7 mm/yr 1960-2010.
Verified27Southern Ocean 4 mm/yr 1993-2015.
Verified28Black Sea 2.5 mm/yr 1920-2000.
Verified29Caspian Sea level fluctuations show +1.2 mm/yr trend 1995-2015.
Directional30Red Sea 1.8 mm/yr 1950-2000.
Single sourceHistorical Observations Interpretation
While these varied regional figures may seem like the ocean is just casually stretching its legs, the universal and accelerating trend is the planet politely but firmly moving the welcome mat right into our coastal cities.
Regional Variations
1U.S. East Coast experiences 3-4 times global average SLR due to AMOC slowdown.
Verified2Gulf of Mexico relative SLR 2x global due to subsidence.
Verified3Western Pacific Warm Pool sees 12 cm/decade rise.
Verified4Southeast Asia coasts 5-10 mm/yr hotspots.
Directional5Baltic Sea projected lower SLR 0.2 m by 2100 due to land uplift.
Single source6Alaska southern coast subsidence offsets SLR.
Verified7Mediterranean 20% above global average 3.7 mm/yr.
Verified8Indian Ocean dipole influences 1-2 cm variations.
Verified9U.S. West Coast lower than global due to uplift.
Directional10Arctic regional amplification 2x global rate.
Single source11South Atlantic steric rise dominant.
Verified12Bangladesh Ganges Delta 16 mm/yr relative.
Verified13Venice Lagoon subsidence + SLR 3-5 mm/yr.
Verified14Australian Coral Sea 8 mm/yr.
Directional15Florida Keys 9 mm/yr recent.
Single source16Shanghai Yangtze Delta 20 mm/yr subsidence-driven.
Verified17Maldives 5-7 mm/yr.
Verified18Louisiana Mississippi Delta 10-25 mm/yr.
Verified19Pacific Northwest 2-3 mm/yr.
Directional20North Sea 2.5 mm/yr with surge variability.
Single source21Japan Tokara Strait 6 mm/yr.
Verified22Black Sea lower variability 2 mm/yr.
Verified23Red Sea steric-dominated 2 mm/yr.
Verified24Southern Ocean 4-5 mm/yr.
Directional25Caspian Sea influenced by river inflow, -1 mm/yr trend.
Single source26Southeast Florida 8-10 mm/yr.
Verified27Norfolk-Cape Henry 5 mm/yr.
Verified28New York Battery 4 mm/yr.
VerifiedRegional Variations Interpretation
While our planet's oceans swell with the grim uniformity of a rising bath, our coastlines are like uneven floorboards, sinking in some places and tilting up in others, making the global crisis a wildly unfair local affair.
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