Environment

25-year study shows sea level rise is accelerating

A new study of 25 years' worth of data has found that the rate of sea level rise is accelerating
A new study of 25 years' worth of data has found that the rate of sea level rise is accelerating
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A new study of 25 years' worth of data has found that the rate of sea level rise is accelerating
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A new study of 25 years' worth of data has found that the rate of sea level rise is accelerating

A team of scientists has studied 25 years' worth of satellite data, and calculated that the sea level isn't rising at a steady rate, it's accelerating. If the trend continues, the total sea level rise could be twice as high as previous projections by 2100.

It's been observed for decades that the sea level is rising, with the waves lapping about 2.6 in (6.6 cm) higher on average in 2014 than they were in 1993. To study just how fast it's rising, the researchers looked at altimeter measurements gathered over the last 25 years by satellites such as TOPEX/Poseidon and the three Jason satellites, as well as ground-based tide gauge data and climate simulations.

Altogether, the researchers calculated that the rate of sea level rise is accelerating by about 0.08 mm per year. If left unchecked, that trend could mean the seas would rise by at least 10 mm per year by the end of the century, which would wreak plenty of havoc on the world's coastal cities.

"This acceleration, driven mainly by accelerated melting in Greenland and Antarctica, has the potential to double the total sea level rise by 2100 as compared to projections that assume a constant rate — to more than 60 cm (23.6 in) instead of about 30 (11.8 in)," says Steve Nerem, lead researcher on the project. "And this is almost certainly a conservative estimate. Our extrapolation assumes that sea level continues to change in the future as it has over the last 25 years. Given the large changes we are seeing in the ice sheets today, that's not likely."

Satellite altimeter data alone doesn't paint a clear enough picture, due to fluctuations caused by El Niño and La Niña weather patterns, and events like volcanic eruptions. To see through these outliers to the underlying trend, the scientists used climate models that determine how much of an effect these events would have. Tide gauge data, gathered by ground-based stations all over the world, can also chip in to counter any potential errors in the altimeter readings.

"The tide gauge measurements are essential for determining the uncertainty in the GMSL (global mean sea level) acceleration estimate," says Gary Mitchum, co-author of the study. "They provide the only assessments of the satellite instruments from the ground."

The researchers say that their findings are just the beginning. The 25-year period studied so far is long enough for the acceleration to be detected, but further data will be gathered by the ongoing Jason-3 project and other altimetry satellites, as well as more advanced ground stations.

The research team involved scientists from the Cooperative Institute for Research in Environmental Sciences (CIRES), the University of Colorado Boulder, the University of South Florida, NASA Goddard Space Flight Center, Old Dominion University, and the National Center for Atmospheric Research.

The study was published in the journal Proceedings of the National Academy of Sciences.

Source: CIRES

12 comments
aksdad
Standard practice for climate alarmists: if the data doesn’t support your narrative, torture it until it does. Measurements of sea level by satellite started in 1993, 25 years ago. Records of sea level rise by tide gauges go back to 1870, almost 150 years. You can see both at https://climate.nasa.gov/vital-signs/sea-level/. In neither record is there any obvious acceleration of sea level rise, which has been inconvenient for the alarmist’s story that sea level rise is accelerating. There are brief periods during major El Niños when it increases for a year or two followed by level—or even decreasing—sea levels, but the long-term trend over the last 150 years has been fairly consistent. The only “acceleration” in sea level rise was clear back around 1930, long before human CO2 emissions could have had any measurable effect on climate. The really funny thing about satellite measurements and this flawed study is that satellite telemetry isn’t anywhere close to millimeter precision. The ostensibly sub-millimeter precision (3.2 mm/yr) is an artifact of statistical analysis. The even funnier thing is that up until just a few days ago, NOAA and NASA (and CU website at http://sealevel.colorado.edu/) reported the 25-year trend as 3.4 mm/yr but they have just adjusted it downward to 3.1 mm/yr. In other words their own data shows global sea level rise DECELERATED slightly, but only those who have been paying atttention regularly would know that.
over_there
when climate research dosnt give the answer you want its always el nino hiding the true effects except for when the numbers were all wrong and you had to correct them to match the changes you want to find.
Nik
When studying statistics at engineering college, it was commented, that you can prove just about anything with statistics, but whatever you prove may have absolutely no connection with reality, as it depends on what methods you choose to manipulate them. My home town is on a tidal estuary, and there has been no noticeable rise in sea level there. in some places, the road alongside the estuary is at almost high tide level, and used to be flooded on extra high tides. That has not happened in many years. In fact large areas of mudflats are now covered in grass, which would tend to indicate a fall in average sea level, rather than a rise. ('When the observed facts do not fit the theory, then no matter how elegant the theory, the theory is wrong!'....... Richard Feynman.)
VincentWolf
Nik: Your making the assumption that the ground itself has not risen. Perhaps the grass is showing because other areas have subsided and your 'grass' area has risen. Bad logic.
Catweazle
"This acceleration, driven mainly by accelerated melting in Greenland and Antarctica" Really... "Greenland Ice Sheet's 2017 weigh-in suggests a small increase in ice mass" https://www.climate.gov/news-features/understanding-climate/greenland-ice-sheets-2017-weigh-suggests-small-increase-ice-mass "Mass gains of the Antarctic ice sheet exceed losses" https://www.cambridge.org/core/journals/journal-of-glaciology/article/mass-gains-of-the-antarctic-ice-sheet-exceed-losses/983F196E23C3A6E7908E5FB32EB42268
Biker Bill
I can't speak for the rest of the planet, but I have lived on a bluff in Encinitas, California for over 60 years. We were told that our bluff would erode away and our home would end up in the pacific ocean. I'm still here, my home is still here, and the bluff looks exactly the same as it did 60 years ago. So I see no evidence that the ocean waters are rising. The only thing that has risen dramatically is the value of my property.
christopher
There is not 25years of useable satellite data, and the data there is gets calibrated from one spot on land, and as everyone knows, every spot of land on earth is moving either up or down itself, including the shorelines of every city on the coast, and they're not all going the same direction. On Australia's east coast, for example, the land is rising relative to the sea. Get some perspective everyone.
guzmanchinky
Hard to believe how many deniers read a science site like Newatlas. Yes sea levels are rising, it is easy to measure, and they will rise more quickly. What's even more troubling is the level of ignorance about how a few anecdotal observations by laypeople serves to confirm their political agenda. I for one will not be investing in low lying land anytime soon...
bwana4swahili
At least there is an upside to this trend! When all the ice on Earth is melted, sea levels can't go any higher...
ljaques
OHMIGODWEREALLGONNADIE...again. Brought to you by people who have taken "climate change studies" in the Uni. How could it not be so?