John’s Blog/Newsletter: SEA LEVEL RISE NOW

A New Year, A New Video Series “The Sea Level Minute”

A very Happy New Year to all of my readers. As we begin 2019 I am excited to tell you about a new program I am working on through the non-profit International Sea Level Institute. We will be launching a new video series called the Sea Level Minute.

There is so much bad information about sea level rise in circulation. We felt it was important to create this free public education series to explain the facts and fictions about how sea level rise will affect all of us. Here are just a few of the topics that we plan on covering in these one-minute videos:

Why is sea level rising?
Can sea level rise be stopped?
How high could sea level rise in 30 years?
Why do the projections vary so much?
How soon could sea level rise affect property values?
Are there any solutions?
What can be done to adapt to higher sea level?

Initially, the Institute would like to produce 20 videos in the first series. We have launched a Crowdfunding campaign to help raise the $20,000 needed to professionally produce these important videos. The first one in the series has been produced and you can watch it by going to www.sealevelminute.johnenglander.net or simply click on the image below. You will be brought to our crowdfunding page where you can read more about this new program. We hope you will consider making a donation and supporting this important effort by sharing this crowdfunding link with your social networks.

Best wishes to all for a healthy and happy New Year!

By John Englander December 31, 2018 Sea Level Rise

4 Comments

Char D

- 6 years ago Reply

Sea level rise concerns are local, not global. Most of the regions where sea level rise is a concern (i.e., the Gulf of Mexico, U.S., Southern Florida, U.S.) are result of land subsidence, not sea level rise.

On a global scale, satellites reveal that there is more land area above sea level today than there was in the 1980s (see the 4 scientific papers below for verification). In other words, sea level rise cannot keep up with geological processes, and more uplift than subsidence is occurring on net across the globe, allowing for stable to slightly increasing shorelines along coasts (again, on net). Sea level rise rates and climatic factors have far less significance compared to geological processes in determining relative sea level.

The alarmist nature of your blog – and the assumption that human influence on sea level is determinative – lacks observational and thus scientific validation.
—
http://www.nature.com/nclimate/journal/v6/n9/full/nclimate3111.html
Earth’s surface water change over the past 30 years [1985-2015] – “Earth’s surface gained 115,000 km2 of water and 173,000 km2 of land over the past 30 years, including 20,135 km2 of water and 33,700 km2 of land in coastal areas.”
—
http://www.bbc.com/news/science-environment-37187100
“Coastal areas were also analysed, and to the scientists’ surprise, coastlines had gained more land – 33,700 sq km (13,000 sq miles) – than they had been lost to water (20,100 sq km or 7,800 sq miles).”

“’We expected that the coast would start to retreat due to sea level rise, but the most surprising thing is that the coasts are growing all over the world,’ said Dr Baart. ‘We’re were able to create more land than sea level rise was taking.’”
—
Duvat et al., 2018
https://onlinelibrary.wiley.com/doi/abs/10.1002/wcc.557
“This review first confirms that over the past decades to century, atoll islands exhibited no widespread sign of physical destabilization by sea-level rise. The global sample considered in this paper, which includes 30 atolls and 709 islands, reveals that atolls did not lose land area, and that 73.1% of islands were stable in land area, including most settled islands, while 15.5% of islands increased and 11.4% decreased in size. Atoll and island areal stability can therefore be considered as a global trend. Importantly, islands located in ocean regions affected by rapid sea-level rise showed neither contraction nor marked shoreline retreat, which indicates that they may not be affected yet by the presumably negative, that is, erosive, impact of sea-level rise. … These results show that atoll and island areal stability is a global trend, whatever the rate of sea-level rise. Tuvaluan atolls affected by rapid sea-level rise (5.1 mm/yr; Becker et al., 2012) did not exhibit a distinct behavior compared to atolls located in areas showing lower sea-level rise rates, for example, the Federated States of Micronesia or Tuamotu atolls.”
—
Luijendijk et al., 2018
https://www.nature.com/articles/s41598-018-24630-6
“The application of an automated shoreline detection method to the sandy shorelines thus identified resulted in a global dataset of shoreline change rates for the 33 year period 1984–2016. Analysis of the satellite derived shoreline data indicates that 24% of the world’s sandy beaches are eroding at rates exceeding 0.5 m/yr, while 28% are accreting and 48% are stable.”
—
Kench et al., 2018
https://www.nature.com/articles/s41467-018-02954-1
“We specifically examine spatial differences in island behaviour, of all 101 islands in Tuvalu, over the past four decades (1971–2014), a period in which local sea level has risen at twice the global average (Supplementary Note 2). Surprisingly, we show that all islands have changed and that the dominant mode of change has been island expansion, which has increased the land area of the nation. … Using remotely sensed data, change is analysed over the past four decades, a period when local sea level has risen at twice the global average [<2 mm/yr-1] (~3.90 ± 0.4 mm.yr−1). Results highlight a net increase in land area in Tuvalu of 73.5 ha (2.9%), despite sea-level rise, and land area increase in eight of nine atolls."

John

- 6 years ago Reply

That’s an interesting, even erudite view, but I disagree with your analysis and conclusions.

Fundamentally your case seems to be that the presently observable sea level rise (SLR) is because of subsidence, such as New Orleans or Norfolk. While true that is where SLR is greatest I fully account for those extraordinary factors in local SLR, just as we account for the land uplifting due to glacial rebound in areas like Alaska and Scandinavia. We know that that dynamic is at works. But it does not detract from the basics, that from ice on land melting and thermal expansion of seawater due to warming the global ocean is getting higher at about 2 tenths of an inch a year. May not seem like much but even a drip will fill a bucket and the melting is quickly accelerating.
Briefly:
1. Looking at your second reference the BBC story, it does agree with you that more land has been added than lost, but their largest example of land being added is the disappearance of the inland Aral Sea, previously the fourth largest lake in the world. The addition of that land has no reflection on global sea level rise, as a force to move shorelines inland and is not relevant to whether global SLR is moving shorelines inland.
2. I am not aware of any dispute that the glacial cycles of the last few million years (the Quaternary) have had sea level cycling up and down about a hundred meters, as the ice sheets respond to the roughly five degree average global temperature change. As described in various papers such as Archer & Brovkin 2009 https://geosci.uchicago.edu/~archer/reprints/archer.2008.tail_implications.pdf that equates to 10-20 meters of vertical SL change per degree C. We have already had that much warming, and are headed higher of course. So there are MANY meters of sea level rise, already committed.
3. As looking for observational data, even at the present accelerated rate of melting, SLR is only about 5 mm a year, or about 20 inches a century. The two tenths of an inch each year is not observable in the usual sense, but not only do the satellites measure it, it corroborates with the century of tide gauge data. The fact that it is accelerating in some exponential manner, is the cause for concern, due to where it is headed, not because it has already put large land areas underwater.
4. The melting and collapse of the Greenland ice sheet, the other ice in the Arctic, and the early evidence of temperature increase in Antarctica are all observations that support my case.

I am sure you are aware that my descriptions are in line with mainstream reports such as:
US National Climate Assessment, compiled by 13 Federal Agencies https://science2017.globalchange.gov/downloads/CSSR2017_FullReport.pdf
NOAA’s Technical Report on Sea Level Rise https://tidesandcurrents.noaa.gov/publications/techrpt83_Global_and_Regional_SLR_Scenarios_for_the_US_final.pdf
Dept of Defense (SERDP) Report on the risk of SLR: https://www.serdp-estcp.org/Program-Areas/Resource-Conservation-and-Resiliency/Infrastructure-Resiliency/Regional-Sea-Level-Scenarios-for-Coastal-Risk-Management
as well as international efforts like the IPCC, Germany’s Potsdam Institute, etc.

If you do not want to accept their analysis of satellite and other data that warns of disastrous future sea level rise, based on the current temperatures, the geologic record, and the early stages of glaciers and ice sheets melting I would direct you to take it up with them as they have the resources to debate this with you further.

Thank you.

Char D

- 6 years ago Reply

“But it does not detract from the basics, that from ice on land melting and thermal expansion of seawater due to warming the global ocean is getting higher at about 2 tenths of an inch a year.”

Again, those “basics” miss the point. Sea level rise is only a problem if it engulfs coasts, shorelines, and low-lying land area where human populations reside. In some local areas, especially where the land is subsiding, it’s doing that, yes. But on a global scale, more land area is *above* sea level today than in the 1980s. That’s the key observational evidence (from satellite data). Observations don’t care whether there are other organizations agree with you or not about how dire the situation is or will turn out to be someday. In the tropical Pacific, where sea levels are rising faster than just about anywhere in the world (5-6 mm/yr), the coasts and shorelines of the islands are nonetheless expanding. Climate change and sea level rise cannot keep up with natural geological processes. Again, it doesn’t matter if you disagree. That’s what the satellite observations show.

1. “The addition of that land has no reflection on global sea level rise”

Correct. But it’s the other way around (and a little different wording). Local sea level rise has little to no impact on coastal land area relative to the impact of naturally fluctuating geological processes.

2. “As described in various papers such as Archer & Brovkin 2009 … that equates to 10-20 meters of vertical SL change per degree C.”

John, that sea level addition from melting ice sheets applies when the starting point for the ice sheet melt is glacial/ice age conditions such as the LGM 20,000 years ago — when the UK, Russia, Canada, the northern half of the U.S. states, etc., were covered by kilometers-thick ice sheets. *That’s* the meltwater that filled the basins at rates of 1 to 5 meters per century (14,700 to 8,000 years BP), allowing sea levels to rise by 120 meters from the last glacial to this interglacial, reaching a highstand of about 2-3 meters above today’s levels in the Mid-Holocene. After the continental ice melts, what’s left is polar ice and mountain glaciers during interglacials. There is a limit to how much polar ice sheets (Greenland, Antarctica) can melt, especially since the temperature ranges between about +5 to -40 degrees C for both poles. Lapse rate temperature determinants limit mountain glacier melt. In sum, your 10-20 m per degree C figure is the glacial-to-interglacial value. This doesn’t apply to interglacials, as there is no more continental ice to melt.

3. “As looking for observational data, even at the present accelerated rate of melting, SLR is only about 5 mm a year, or about 20 inches a century.”

During the 56 years between 1958-2014, observations show that sea levels rose at a rate of about 1.4 mm/yr, or about 6 inches per century. (That includes 1.5 mm/yr measured and 1.3 mm/yr for the sum of contributors – ice sheet melt, thermal expansion especially.) The total contribution from Greenland and Antarctica combined was about 1.52 cm during that time (according to Frederikse et al., 2018, below). Only 1.52 cm of meltwater addition over the course of 56 years would not appear to be severe enough to unleash *meters* of sea level rise.

Frederikse et al., 2018
https://journals.ametsoc.org/doi/10.1175/JCLI-D-17-0502.1
“For the first time, it is shown that for most basins the reconstructed sea level trend and acceleration can be explained by the sum of contributors, as well as a large part of the decadal variability. The global-mean sea level reconstruction shows a trend of 1.5 ± 0.2 mm yr−1 over 1958–2014 (1σ), compared to 1.3 ± 0.1 mm yr−1 for the sum of contributors.”

4. “The melting and collapse of the Greenland ice sheet, the other ice in the Arctic, and the early evidence of temperature increase in Antarctica are all observations that support my case.”

Greenland has only added 1.5 cm to sea level rise between 1900 and 2010 (Fettweis et al., 2017). Again, 1.5 cm in 110 years does not suggest we’ll be getting *meters* of sea level rise in the next 80 years.

Fettweis et al., 2017
http://www.the-cryosphere.net/11/1015/2017/tc-11-1015-2017.pdf
“Finally, with respect to the 1961–1990 period, the integrated contribution of the GrIS SMB anomalies over 1900–2010 is a sea level rise of about 15 ± 5 mm [1.5 cm], with a null contribution from the 1940s to the 2000s”

As far as observations that “support [your] case”, it again doesn’t matter if you have a bunch of organizations that agree with you that sea levels are rising so fast they are a threat to the Earth’s coasts. The observations that show coastal land area is expanding across the globe (on net) undermine the claims that sea level rise, by itself, is a primary determinant of shoreline changes, water in the streets, buildings sinking into the sea, etc.

Char D

- 6 years ago Reply

Piecuch et al., 2018
https://www.nature.com/articles/s41586-018-0787-6
“Here we analyse instrumental data and proxy reconstructions using probabilistic methods to show that vertical motions of Earth’s crust exerted the dominant control on regional spatial differences in relative sea-level trends along the US East Coast during 1900–2017, explaining most of the large-scale spatial variance. Rates of coastal subsidence caused by ongoing relaxation of the peripheral forebulge associated with the last deglaciation are strongest near North Carolina, Maryland and Virginia. Such structure indicates that Earth’s elastic lithosphere is thicker than has been assumed in other models. We also find a substantial coastal gradient in relative sea-level trends over this period that is unrelated to deglaciation and suggests contributions from twentieth-century redistribution of ice and water.”

“Our results indicate that the majority of large-scale spatial variation in long-term rates of relative sea-level rise on the US East Coast is due to geological processes that will persist at similar rates for centuries.”

“We note that negative VLM [vertical land motion] reflects subsidence and hence contributes to sea-level rise. Correspondingly, the most negative VLM [vertical land motion] rate (−2.5 ± 0.6 mm yr−1) is likely (P = 0.75) to occur in the states that host the maximum sea-level rise, North Carolina or Virginia, whereas the most positive rate of VLM (0.7 ± 0.8 mm yr−1) is very likely (P = 0.90) to occur in Maine (Fig. 1g).”