Research team detects an acceleration in the 25-year satellite sea level record

February 12, 2018, University of Colorado at Boulder
Credit: CC0 Public Domain

Global sea level rise is not cruising along at a steady 3 mm per year, it's accelerating a little every year, like a driver merging onto a highway, according to a powerful new assessment led by CIRES Fellow Steve Nerem. He and his colleagues harnessed 25 years of satellite data to calculate that the rate is increasing by about 0.08 mm/year every year—which could mean an annual rate of sea level rise of 10 mm/year, or even more, by 2100.

"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 instead of about 30." said Nerem, who is also a professor of Aerospace Engineering Sciences at the University of Colorado Boulder. "And this is almost certainly a conservative estimate," he added. "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."

If the oceans continue to change at this pace, sea level will rise 65cm (26 inches) by 2100—enough to cause significant problems for coastal cities, according to the new assessment by Nerem and several colleagues from CU Boulder, the University of South Florida, NASA Goddard Space Flight Center, Old Dominion University, and the National Center for Atmospheric Research. The team, driven to understand and better predict Earth's response to a warming world, published their work today in the journal Proceedings of the National Academy of Sciences.

Rising concentrations of greenhouse gases in Earth's atmosphere increase the temperature of air and water, which causes sea level to rise in two ways. First, warmer water expands, and this "thermal expansion" of the oceans has contributed about half of the 7 cm of global mean we've seen over the last 25 years, Nerem said. Second, melting land ice flows into the ocean, also increasing sea level across the globe.

These increases were measured using satellite altimeter measurements since 1992, including the U.S./European TOPEX/Poseidon, Jason-1, Jason-2, and Jason-3 satellite missions. But detecting acceleration is challenging, even in such a long record. Episodes like volcanic eruptions can create variability: the eruption of Mount Pinatubo in 1991 decreased global mean sea level just before the Topex/Poseidon satellite launch, for example. In addition, can fluctuate due to climate patterns such as El Niños and La Niñas (the opposing phases of the El Niño Southern Oscillation, or ENSO) which influence ocean temperature and global precipitation patterns.

Twenty-five years of satellite data confirm rising sea levels
Jason-3 satellite mission helped detect an acceleration in sea level rise. Credit: NOAA

So Nerem and his team used climate models to account for the volcanic effects and other datasets to determine the ENSO effects, ultimately uncovering the underlying sea-level rate and acceleration over the last quarter century. They also used data from the GRACE satellite gravity mission to determine that the acceleration is largely being driven by melting ice in Greenland and Antarctica.

The team also used tide gauge data to assess potential errors in the altimeter estimate. "The tide gauge measurements are essential for determining the uncertainty in the GMSL (global mean sea level) acceleration estimate," said co-author Gary Mitchum, USF College of Marine Science. "They provide the only assessments of the satellite instruments from the ground." Others have used tide gauge data to measure GMSL acceleration, but scientists have struggled to pull out other important details from tide-gauge data, such as changes in the last couple of decades due to more active ice sheet melt.

"This study highlights the important role that can be played by satellite records in validating climate model projections," said co-author John Fasullo, a climate scientist at the National Center for Atmospheric Research. "It also demonstrates the importance of climate models in interpreting records, such as in our work where they allow us to estimate the background effects of the 1991 eruption of Mount Pinatubo on global sea level."

Although this research is impactful, the authors consider their findings to be just a first step. The 25-year record is just long enough to provide an initial detection of acceleration—the results will become more robust as the Jason-3 and subsequent altimetry satellites lengthen the time series.

Ultimately, the research is important because it provides a data-driven assessment of how sea level has been changing, and this assessment largely agrees with projections using independent methods. Future research will focus on refining the results in this study with longer time series, and extending the results to regional , so they can better predict what will happen in your backyard.

Explore further: Volcanic eruption masked acceleration in sea level rise

More information: R. S. Nerem el al., "Climate-change–driven accelerated sea-level rise detected in the altimeter era," PNAS (2018). www.pnas.org/cgi/doi/10.1073/pnas.1717312115

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JamesG
1 / 5 (18) Feb 12, 2018
And yet Pacific Islands are actually growing. Weird.
Kalopin
1 / 5 (15) Feb 12, 2018
...would like to make formal request for NASA, USGS, NOAA,... to conduct planetary weight and balance to determine the possibility for another Lunar impact...

... too much water-weight near the equator and not enough ice at the poles will cause planetary imbalance, alternating polar vortices, excessive wobble on axis, allowing the Moon to, once again, impact...
leetennant
5 / 5 (15) Feb 12, 2018
...would like to make formal request for NASA, USGS, NOAA,... to conduct planetary weight and balance to determine the possibility for another Lunar impact...

... too much water-weight near the equator and not enough ice at the poles will cause planetary imbalance, alternating polar vortices, excessive wobble on axis, allowing the Moon to, once again, impact...


We need research into the unicorns STAT
leetennant
5 / 5 (20) Feb 12, 2018
And yet Pacific Islands are actually growing. Weird.


I'm assuming you're talking about this article https://phys.org/...ger.html

You know that confirmation basis is working overtime when you can read that and decide that all Pacific Islands are growing. Tuvalu is just one and with sea level rises in that area of the world double the rate elsewhere, there's clearly some other phenomena going on, probably volcanic. These areas are not geologically stable. That does not necessarily translate to good news.
Kalopin
1.7 / 5 (6) Feb 12, 2018
And yet Pacific Islands are actually growing. Weird.

I'm assuming you're talking about this article https://phys.org/...ger.html
You know that confirmation basis is working overtime when you can read that and decide that all Pacific Islands are growing. Tuvalu is just one and with sea level rises in that area of the world double the rate elsewhere, there's clearly some other phenomena going on, probably volcanic. These areas are not geologically stable. That does not necessarily translate to good news.

...the western edge of the Pacific plate is rising, from pressure of the Juan de Fuca, Nazca and American plates riding up on top...
...and, if it doesn't split, where it is already cracked, from the Aleutian islands to the Hawaiian islands, which would also be very catastrophic, then it will eventually ride up on the Eurasian plate, sinking the islands of Japan, Taiwan, Korean peninsula, much of China and a great amount of Russia..
greenonions1
5 / 5 (13) Feb 12, 2018
leetenant
I'm assuming you're talking about this article https://phys.org/...ger.html
And if you notice the rush by aksdad, and captbob to declare that sea level rise is not accelerating - despite presented data to the contrary. Today's article is just another piece in the puzzle.

So will they ever give up - and say 'wow - maybe the scientists knew what they were talking about?'
Caliban
5 / 5 (12) Feb 12, 2018

[...]American plates riding up on top...
...and, if it doesn't split, where it is already cracked, from the Aleutian islands to the Hawaiian islands, which would also be very catastrophic, then it will eventually ride up on the Eurasian plate, sinking the islands of Japan, Taiwan, Korean peninsula, much of China and a great amount of Russia]


@kalopin,

Sure, what you say is true, but only so far as it goes.

There is much greater complexity involved than you have pointed out, and the timescale is literally Geologic. None of your predictions will happen any time soon, as we are talking about events that will occur in millions or tens of millions of years.

Far more likely in the next hundreds-to-kilo years are supervolcanic eruptions or megaquakes, both of which appear to be somewhat overdue based upon the geologic record.

And, of course, AGW --which is happening RIGHT NOW.
Kalopin
1 / 5 (2) Feb 12, 2018
https://phys.org/...sgs.html "...Japan's recent massive earthquake, one of the largest ever recorded, appears to have moved the island by about eight feet (2.4 meters), the US Geological Survey said..."
"...but a colossal earthquake can provide enough of a jolt to dramatically move the plates, with catastrophic consequences.
"With an earthquake this large, you can get these huge ground shifts," Earle said. "On the actual fault you can get 20 meters (65 feet) of relative movement, on the two sides of the fault."

I don't know, eight feet from one sequence of events?

...please, if you may find time, go through my findings, as I believe there may be somewhat of a time discrepancy? https://www.linke...ny-hood/
..."geologic timescale" for many features actually spans a much shorter time period...
[believe this-"truth is stranger than fiction" but evidence speaks for itself.
HeloMenelo
4.7 / 5 (13) Feb 13, 2018
Antigoracle keeps churning out new puppets like french fries. Clearly one of hi latest puppets jamesg, rushing to conclusions he has yet to even comprehend, it seems everything he cannot understand seems 'weird' to him, try understanding the word science before babbling claptrap.

Perhaps i should leave a comment after all on that chimpanzee self control article ? ;)
aksdad
1.4 / 5 (9) Feb 13, 2018
Ha ha ha haaaaa! NASA and the University of Colorado at Boulder just updated their 25-year trend estimates and revised them DOWNWARD from 3.4 mm/yr to 3.2 mm and 3.1 mm/yr, respectively. See here:

NASA: https://climate.n...a-level/

CU: http://sealevel.colorado.edu/

So I guess in climate alarmism's opposite world, a decreasing trend is called "acceleration", rotl! Proof, once again, that climate alarmists are experts at getting their "models" to describe their fantasy world rather than the actual world the rest of us live in. Alert human rights organizations; there is some serious data torture going on here.
aksdad
1.9 / 5 (9) Feb 13, 2018
For your enjoyment, here is University of Colorado at Boulder's Sea Level Research Group page from February 9:

http://sealevel.colorado.edu/" title="http://web.archive.org/web/20180209002147/http://sealevel.colorado.edu/" rel="nofollow" target="_blank">http://web.archiv...ado.edu/

And here it is today:

http://sealevel.colorado.edu/

The 25 year trend from satellite telemetry was revised downward from 3.4 mm/yr to 3.1 mm/yr. With no trace of irony they post underneath the graph that sea level rise is accelerating. Doh!

Meanwhile the tide gauge data going back almost 150 years shows average global sea level rise is about 1.5 mm/yr.

https://climate.n...a-level/

(2nd graph, 200 mm / 130 years = 1.54 mm/yr)

Who you gonna believe? A study done by climate alarmists with computer models designed to produce a preconceived outcome or your own lying eyes?
aksdad
1 / 5 (7) Feb 13, 2018
Hmmm this website has trouble displaying the Internet Archive URL. Once again, for sealevel.colorado.edu from February 9, 2017:

http://web.archiv...ado.edu/

If that doesn't work, go to web.archive.edu and look up sealevel.colorado.edu for February 9, 2017 (or earlier).
aksdad
1 / 5 (7) Feb 13, 2018
Sorry, that's February 9, 2018. Any date in the last couple years will show the same thing, 3.4 mm/yr sea level rise. It was revised sometime in the last few days to show 3.1 mm/yr. Which works out to 13.4 inches (now 12.2 inches) per century, still way above the 1.54 mm/yr from tide gauges (6.1 inches per century), for which there is a record stretching back almost 150 years.

Let's not forget that at the peak of the prior warm interglacial period 125,000 years ago that sea levels were 4 to 6 meters (13 to 20 feet) higher, all without "human-caused" warming. So at current rates, we'll hit those levels in another 1300 to 2600 years. Better start puttting up sandbags.

https://www.giss....nitz_09/
humy
5 / 5 (11) Feb 13, 2018
And yet Pacific Islands are actually growing. Weird.

JamesG

No it isn't 'weird' in the slightest.
Firstly, they are not all growing; just like most islands across the world, many are currently strinking.
Secondly, it is well known that some islands are growing despite current sea level rise because either the movement of tectonic plates or volcanism, exactly as predicted, is causing them to rise at a faster rate than current sea level rise. There is no mystery here and everything here confirms that the sea level is rising.
antialias_physorg
5 / 5 (13) Feb 13, 2018
And yet Pacific Islands are actually growing. Weird.

Ya know, that's an argument on the level of "The sun exists, yet every night it gets dark. Weird"

Not even a toddler would argue that way. Are you a mental toddler?
TechnoCreed
5 / 5 (3) Feb 13, 2018
aksdad used way too many words to demonstrate that there are discrepancies between dataset from one year to another in sea level rise. Indeed, those datasets need to be readjusted when they diverge from altimetry measurements. The best way to follow sea level rise is to go to this web page: https://www.aviso...ges.html What is amazing about it is that you can select a specific time period... or simply click on the last five years to see what is recently happening with sea level rise.
MR166
1 / 5 (5) Feb 13, 2018
Also note that the rate changed the most during the 2013-2016 time period. That was an El Nino period. This is considered weather due to the short time span. Projecting out an average after just hitting a peak is known as cherry picking one's data.
Kalopin
1 / 5 (3) Feb 13, 2018
https://www.energ...in-2018/
"...Increased production from tight rock formations within the Permian region in Texas and New Mexico accounts for 0.8 million b/d of the expected 1.2 million b/d of crude oil production growth from December 2017 to December 2019. EIA expects most of the remaining 0.3 million b/d of growth to come from the Federal Gulf of Mexico, as seven new projects are expected to come online by the end of 2019..."

[...yea, ask me how this is relevant... ;-]
MR166
1.5 / 5 (8) Feb 13, 2018
Thanks for the links Askdad. Using NASA's very own site it is obvious that they cannot even measure sea level change within 1.5 mm/year. If they could the satellite and tide gauge's rate of change would match. Yet these clowns claim to be able to measure the rate of change of the rate of change to .08mm/year accuracy from only 25 years worth of data. They then have the nerve to project their invalid result out 75 years and tell us we are all going to die.

Oh this has to be correct it is peer reviewed. Yea, right!!!!
TrollBane
5 / 5 (3) Feb 13, 2018
"[...yea, ask me how this is relevant... ;-]
"
Nah, I'll just give it the one-rating it deserves. :-]
MR166
1 / 5 (5) Feb 14, 2018
More than likely the orbit of the satellite is declining by 1.5 mm/year more than they know and that is the difference between the land and satellite readings.
MR166
1 / 5 (4) Feb 14, 2018
Kalopin
1 / 5 (4) Feb 14, 2018
http://notrickszo...MzM.dpbs

Another viewpoint.

[from link- "...Not only has East Antarctica been gaining mass, the author goes on to say that it would take 100s of thousands to millions of years for Antarctica to even exhibit partial retreat. So much for the "if it melted in its entirety" warning we read earlier..."

see?, no!, a comet could impact Antarctica, and then...?
...there is NO planetary defense!
...

[...I believe there may be a lack of understanding concerning catastrophism?... ;-]
Kalopin
1 / 5 (3) Feb 14, 2018
"[...yea, ask me how this is relevant... ;-]
"
Nah, I'll just give it the one-rating it deserves. :-]


...why?, do you not understand what will occur after the tectonic plates have lost their integrity, and that much volume, weight, and pressure has been removed and displaced?...
...would you like to know? ... ;-]]]]]]]
Kalopin
1 / 5 (2) Feb 16, 2018
https://www.mirro...facebook
"...Because glaciers are at high latitudes, when they melt they're distribute water from these high latitudes towards lower latitudes,..."
...surely they realize that the greatest majority of oil and gas is also being moved from upper latitudes toward the equator?...
"...2018, the two countries doubled China's ESPO crude import capacity to 30 million tons..."
https://aawsat.co...-oil-gas
"...U.S. and China recently agreed to a major liquid natural gas (LNG) trade deal, which could generate $26 billion..."
http://nationalin...na-20677
?...
TechnoCreed
5 / 5 (3) Feb 17, 2018
"[...yea, ask me how this is relevant... ;-]
"
Nah, I'll just give it the one-rating it deserves. :-]


...why?, do you not understand what will occur after the tectonic plates have lost their integrity, and that much volume, weight, and pressure has been removed and displaced?...
...would you like to know? ... ;-]]]]]]]

Why would you think that studying the earth's variations in motion would be catastrophism? Why not just an interesting subject to tackle?
Here is the interesting paper that came out of it: http://eps.mcgill...2015.pdf

Are you suggesting that the staggering amount of weight in fossil fuel that is being extracted and transported have any significance in this? O_o
Kalopin
1 / 5 (2) Feb 17, 2018
...yea, it is interesting, to understand the 26ky processional cycle, 100ky glacial cycle coincide with the Moon's orbital elements, and that the last time there developed excessive wobble [imbalance] was the YDB, 13kya...
...each time a major catastrophe, to cause an ice age,...then ok again?, it seems, for around the same amount of time?...
...the pattern,... [...like two tops spinning 'round one another...]

...I did enjoy your paper, though it would have probably helped if the authors would have understood that Pangaea was intact during the previous era?...
...

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