Since 1993, satellites have kept careful watch over the world\u2019s oceans, allowing scientists a clear view of how they are behaving. What they have revealed is alarming.<\/p>\n
Sea level rise was unexpectedly high last year, according to a recent NASA analysis<\/a> of satellite data.<\/p>\n More concerning, however, is the longer-term trend. The rate of annual sea level rise has more than doubled over the past 30 years, resulting in the global sea level increasing 4 inches<\/a> since 1993.<\/p>\n \u201cIt\u2019s like we\u2019re putting our foot on the gas pedal,\u201d said Benjamin Hamlington, a research scientist in the Sea Level and Ice Group at NASA\u2019s Jet Propulsion Laboratory. While other climate signals fluctuate, global sea level has a \u201cpersistent rise,\u201d he told CNN.<\/p>\n It spells trouble for the future. Scientists have a good idea how much average sea level will rise by 2050 \u2014 around 6 inches<\/a> globally, and as much as 10 to 12 inches<\/a> in the US. Past 2050, however, things get very fuzzy.<\/p>\n \u201cWe have such a huge range of uncertainty,\u201d said Dirk Notz, head of sea ice at the University of Hamburg. \u201cThe numbers are just getting higher and higher and higher very quickly.\u201d<\/p>\n The world could easily see an extra 3 feet of sea level rise by 2100, he told CNN; it could also take hundreds of years to reach that level. Scientists simply don\u2019t know enough yet to project what will happen.<\/p>\n What scientists are crystal clear about is the reason for the rise: human-caused global warming.<\/p>\n Oceans absorb roughly 90% of the excess heat primarily produced by burning fossil fuels, and as water heats up it expands. Heat in the oceans and atmosphere is also driving melting of the Greenland<\/a> and Antarctic ice sheets<\/a>, which together hold enough fresh water to raise global sea levels by around 213 feet.<\/p>\n Melting ice sheets have driven roughly two-thirds<\/a> of longer-term sea level rise, although last year \u2014 the planet\u2019s hottest on record \u2014 the two factors flipped, making ocean warming the main driver.<\/p>\n Melting icebergs crowd the Ilulissat Icefjord on July 15, 2024 near Ilulissat, Greenland. – Sean Gallup\/Getty Images<\/p>\n It\u2019s likely that an increase of about 3 feet is already locked in, Notz said, because \u201cwe have pushed the system too hard.\u201d The big question is, how quickly will it happen?<\/p>\n Ice sheets are the biggest uncertainty, as it\u2019s not clear how fast they\u2019ll react as the world heats up \u2014 whether they\u2019ll melt steadily or reach a tipping point and rapidly collapse.<\/p>\n From studying things like ice cores and sediments, scientists know sudden and dramatic melting<\/a> happened thousands of years ago, Notz said, but it\u2019s still unclear how processes may unfold over the next decades and centuries.<\/p>\n Antarctica is \u201cthe elephant in the room,\u201d he said. Alarming changes<\/a> are unfolding on this vast icy continent, which holds enough water to raise levels by 190 feet.<\/p>\n Notz describes the ice sheet as an \u201cawakening giant:\u201d It takes a long time to wake up but once awake, \u201cit\u2019s very, very difficult to put it back to sleep.\u201d<\/p>\n Sea ice floats in the Antarctic Peninsula region, on November 4, 2017, above Antarctica. Scientists are concerned the West Antarctic Ice Sheet may be in a state of irreversible decline directly contributing to rising sea levels. – Mario Tama\/Getty Images<\/p>\n It will take time for scientists to unravel what the future holds for the ice sheets and what that means for sea level rise.<\/p>\n \u201cThere\u2019ll be big uncertainties that persist for decades,\u201d said Robert Nicholls, professor of climate adaptation at the University of East Anglia.<\/p>\n Where is most vulnerable?<\/p>\n The ocean is not flat like a bathtub and there are big variations in the way sea level rise is experienced.<\/p>\n Some parts of the world see higher levels because of a tangle of factors, including regional currents, erosion and land shifts \u2014 some due to natural processes such as tectonic plate movements, others to human activities including fossil fuel and groundwater extraction.<\/p>\n Flood waters inundate a neighborhood on June 13, 2024, in Hallandale Beach, Florida. – Joe Raedle\/Getty Images<\/p>\n A family travel by boat to their home after it flooded during Hurricane Ida on August 31, 2021 in Barataria, Louisiana. – Brandon Bell\/Getty Images<\/p>\n The US coastlines are tracking above global average and toward the upper end of climate model projections, NASA\u2019s Hamlington said.<\/p>\n The Gulf Coast, where land is sinking in large part due to the extraction of oil, gas and groundwater, is a hotspot.<\/p>\n Louisiana is particularly vulnerable as climate change-driven sea level rise meets fast-sinking land. The state has one of the highest rates of land loss in the world<\/a>, with some areas experiencing relative sea level rise nearly four times the global rate.<\/p>\n Outside the United States, low-lying Pacific island nations bear the brunt of sea level rise, which already poses a threat to their existence.<\/p>\n Over the next three decades, islands such as Tuvalu, Kiribati and Fiji will experience at least 6 inches of sea level rise<\/a> even if the world reduces planet-heating pollution, according to NASA.<\/p>\n What are the impacts?<\/p>\n The world\u2019s coastal communities were built with an understanding of where high tides normally reach. \u201cNow we\u2019re shifting that normal\u201d and even tiny shifts can cause big impacts, Hamlington said.<\/p>\n Already, coastal flooding is increasing, even in the absence of big storms or heavy rainfall. High tide flooding is now happening two to three times more often since 1990 along most US Atlantic and Gulf coastlines, said William Sweet, an oceanographer at the National Oceanic and Atmospheric Administration.<\/p>\n Sea level rise also contributes to coastal erosion, chokes sewage systems and causes salty water to seep into underground freshwater supplies.<\/p>\n Rising seas won\u2019t be felt equally. In some places, 6 inches might mean more frequent flooding during high tides; in others, it could lead to constant inundation, with water covering streets and coastal land for months at a time. The difference depends on a range of factors, including land shifts.<\/p>\n The world can adapt to slow sea level rise, Notz said: \u201cWe might have to relocate cities; you might have to move people around,\u201d but there are ways to build and prepare.<\/p>\n This is already happening. \u201cEntire villages in Fiji have been formally relocated,\u201d said Fijian activist George Nacewa, from climate group 350.org, \u201cthe incoming tides are flooding our roads and inundating our crops.\u201d<\/p>\n However, if the pace accelerates rapidly, \u201cit will be very, very difficult to adapt to, because things unfold too quickly,\u201d he said. As ever, it will be the most vulnerable who feel the biggest impacts, he added.<\/p>\n Residents wade through the flooded streets in Fiji’s capital city of Suva on December 16, 2020, ahead of super Cyclone Yasa. – Leon Lord\/AFP\/Getty Images<\/p>\n Seawater floods past a sea wall into the community of Veivatuloa Village, Fiji, July 16, 2022. – Loren Elliott\/Reuters<\/p>\n Many parts of the world aren\u2019t well prepared. Sea level rise is an \u201cunderappreciated\u201d problem as \u201cit\u2019s hard to grasp the implications\u201d of even a few inches of rise, the University of East Anglia\u2019s Nicholls said.<\/p>\n Humans still have control over how fast sea level rises over the next decades and centuries by cutting emissions, Notz noted.<\/p>\n Global levels of planet-heating pollution, however, continue to tick up and the Trump administration is racing to undo climate policies, including slashing Earth science research at NASA<\/a>, sweeping staff cuts at NOAA and withdrawing the US<\/a> from global climate action.<\/p>\n \u201cOne of the big concerns with the current US administration is that they won\u2019t renew satellites,\u201d Nicholls said. This would take eyes off the oceans at a crucial time.<\/p>\n What the world chooses to do is an ethical issue, said Notz.<\/p>\n \u201cThe kind of sea level rise that we have to deal with is so much smaller compared to what future generations have to face,\u201d he said; the real catastrophe will come further down the road when those who have caused the problem are no longer around.<\/p>\n![\"Melting](\"https:\/\/www.europesays.com\/uk\/wp-content\/uploads\/2025\/05\/b7628193c12062e4df24df0518834327.jpeg\"\/)
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