New York State Sea Level Rise:  Fantasy as Law

Opinion by Kip Hansen — 28 February 2024 — 2700 words/13 minutes

In the United States, both Federal and State agencies make pseudo-laws by formalizing “rules” which have the effect of law but are not written by or voted on by the legislators which have the responsibility to make law.

We see this in the fight over CO₂ and PM2.5 rules from U.S. Federal agencies like the EPA.  At the Federal level, the rule making process takes more than a year, usually two or more and includes Public Comment periods.  Rules are difficult to undo – and require the same lengthy process to make a new rule to override the old. 

New York State, currently big on the Climate Crisis, has just proposed a new rule as follows:

Proposed Action: Amendment of Part 490 of Title 6 NYCRR.

Statutory authority: Environmental Conservation Law, section 3-0319

Subject: Science-based State sea level rise projections. — Purpose: To establish a common source of sea-level rise projections for consideration in relevant programs and decision-making.

In plain English, the NY State Department of Environmental Conservation (NYS DEC) proposes a common source of Sea Level Rise Projections to be used statewide for program planning and decisions making.  This sounds good, right?  Can’t have all these different government programs and politicians using different data – that would be a mess.

Let’s see what they are mandating through this rule:

490.1 Purpose: This Part establishes science-based projections of [sea-level rise] sea level rise for New York State’s tidal coast, including the marine coasts of Nassau, Suffolk and Westchester counties and the five boroughs of New York City, and the main stem of the Hudson River, north from New York City to the federal dam at Troy.

Readers unfamiliar with New York State geography can look at this map of NY State – the above paragraph covers all the coastal sections of Long Island, Atlantic and Long Island Sound, and the Hudson River, which is tidal, all the way to Troy, which is north of Albany:

So, we see that besides the usual coastal areas, where we would expect tides, the Hudson River itself is tidal all the way north to “the federal dam at Troy”, which is 160 miles north of The Battery which sits at the southern tip of Manhattan Island (see inset lower right).   The geography dictates that all of the tides up the Hudson River are determined by the tides at the Battery.

So, if we want to know how much sea level rise there has been in the past for Manhattan and all points north on the Hudson River, we must look to the tide gauge at The Battery.  We would be in luck, as that is one of the longest continuous tide gauge records in the United States and is coupled to a continuously operating GPS stations, which allows correction of the tide gauge record for the  vertical land movement (VLM) of the rock to which the tide gauge is attached.  Subtracting the VLM from the Relative Sea Level Rise (RSLR) apparent in the Tide Gauge Record,  we can determine eactly how much the sea surface itself has risen.

According to NOAA’s tide gauge record, The Battery has a long-term, nearly-perfectly linear record of Relative Sea Level Rise over 167 years of 2.92 mm/yr.  It can be highly variable month-to-month.  We can safely just say 3 mm per year and be close enough.

How much of that is subsidence of the structure on which the tide gauge is mounted?  According to the latest study [Wu, P.-C., Wei, M. (M. ), & D’Hondt, S. (2022). “Subsidence in coastal cities throughout the world observed by InSAR”. Geophysical Research Letters ] NY City’s The Battery sees VLM of -1.21 mm/yr.  That is subsidence, downward land movement, of over 40% of the recorded Relative Sea Level Rise, leaving  1.69 mm/yr of upward movement of the actual surface of the sea per year.  That 1.69 is very close to the standardly cited Global Sea Level Rise figure for the 20th Century of 1.7 or 1.8 mm/yr.  (opinions vary – see NOAA here.)

Note that this latest VLM finding is very close to that found in the seminal paper by Snay et al. in 2007 of -1.35 mm/yr for The Battery.

The subsidence at The Battery will not necessarily be reflected in the tidal values up the Hudson River, as coastal New York is thought to be subsiding at a faster rate than areas inland, and the “hinge point” for crustal rebound on the Hudson River is around Kingston, NY, which is about 95 miles north of The Battery, north of which the land begins to rise instead of subside.  

Nonetheless, for our purposes today, when talking about potential Sea Level Rise in the upriver reaches of the Hudson River, we can use 3 mm/yr as the upper bound and 1.7 mm/yr as the lower bound for Sea Level Rise on the tidal Hudson based on historical records corrected for VLM.

The proposed NY State rule calls for replacing the previously used  ClimAID projections, which had been updated in 2014, in this report:

which can be downloaded here.

Let‘s see what the updated projections are as of 2014.

The new rule calls for replacing the projections from the ClimAID 2004 report as updated in 2014.  This newer report updated the base period, changing the base period from 2000-2004  to the twenty years between 1995-2014, but gives no numerical metric – it doesn’t state what they were to use for the average sea level for that time period.    There are so many different methods of determining that base period metric that I will simply fallback on referring to the tide gauge record at The Battery. 

Using the long-term tide gauge record, we see an unchanging trend of 2.9 mm/yr.  The trend for the base period appears to be the same when looking at the whole record. (Technically, using the recorded monthly values, from Jan 1995 through Dec 2014, the linear trend is down…which is what happens when selecting just a small portion of a long-term record).  The previous sentence is an error – depending on and sensitive to the exact starting and ending dates for the base period (Jan or Dec 1995 and Jan or Dec 2014) the trend is either close to 2.9 mm/yr or decidedly flatter.

All of that adds up to this:  The least-wrong projection of future sea level rise for The Battery would be “more of the same” – about 3 mm/yr. – and, if one was overcome by a sudden attack of over-cautiousness, “maybe a little more.”

If we wish to include global warming/climate change in our forecast, then we must do so from one of the following IPCC dates for the start of Climate Change:   1890,  1950 (mid-20^th century) or 1979 [IPCC AR6].  It is obvious from the NOAA Tide Gauge Record of The Battery that the sea level rise rate did not change at any of those dates but has rather remained stubbornly steady at the stated about 3 mm/yr or 30 mm per decade or 300 mm (about 12 inches) per century.

What does the new rule say planners in NY State must consider?  For all of these projections which are from the base period 1995-2014, the date of the report?

The previous version, supposed to be based on the updated NYSERDA report, had these:

The first chart above is from the NY State Register version of the new rule, however, despite claiming that the projections are from the New York State Energy Research and Development Authority (NYSERDA) 2014, they are not the same.  The second chart is the equivalent chart from NYSERDA (2014).  Note that the dates are different and that even for the Low Projection, the new rule adds 10 extra inches (from 15 to 25) to projected SLR in NYC by 2100 without any explanation for the differences from the NYSERDA report.

It has taken a very deep dig to discover that the SLR projections in the new rule are derived from an Interim Version of a report that is to be cited as : Stevens, A., & Lamie, C., Eds. (2024). New York State Climate Impacts Assessment: Understanding and preparing for our changing climate.  (All the available .pdf files are watermarked INTERIM PUBLICATION.)

I’ll come back to how these projections came to be so exceptionally high.

If we just stick to SLR trends, so how much SLR do we need to experience at The Battery to see 6 inches of SLR between 2014 and 2039?  That’s 25 years to see 152 millimeters of SLR; just about exactly 6 mm/yr. 

Low Projection:   Even for the low projection, we would have had to seen twice the rate of SLR, every year since 2014 and every year up to 2039,  as we have actually experienced.  In the 9 years since 2014, we have only had 27-30 mm of SLR leaving 122 mm to be achieved in the next 15 years which would be a rate of a little over 8 mm/yr, nearly triple the current rate.  Likewise, for the 2100 low projection, a rate of about 8 mm/yr for the rest of the century would be required. 

High Projection:  The projection calls for 13 inches or 330 mm between the years 2014 and 2039 – which would require a rate of SLR of 13 mm/yr.  Since it is now 2024, we have only about 15 years left to see the remaining 300 mm (we have already seen 30) which requires 20 mm per year or 8/10^th of an inch, each year, for the next 15 years.

They are just making this rule now, today, this week. 

I would think that those proposing this rule would realize that if they have not seen any increase in SLR rate in the last decade, 2014 to 2024, that it would require something truly extraordinary to see the rate of SLR double or triple over the next 15 years.  And these multiples are just for the Low Projection.

When considering the High Projections to 2100, we find that the projected rate of SLR used in the new rule are the same 20 mm/yr for the 85 years from 2014-2100.  But again, that would have required 20 mm/yr for the last decade as well, which we have not seen.

In short, something is seriously wrong with the projections of Sea Level Rise in this new rule.  They are not based on the 2014 NYSERDA report, but on the new, apparently not yet finalized, New York State Climate Impacts Assessment (2024).  I’ll give you a peek at the full projection from this report for The Battery (click on it for a single page .pdf download):

From the chart above, the Climate Assessment makes this claim:

“Projections for the future: Sea level is projected to rise along the state’s coastline and in the tidal Hudson by about 2 to 3 feet by the end of the century. However, there is a chance of a more dramatic change if part of the Antarctic ice sheet collapses, for example. Such a change is impossible to predict with any certainty, and scientists consider it a “low probability but high impact” event. If it happens, New York could experience sea level rise of about 7 to 10 feet by the end of the century.”

How in the world do they arrive at such hysterical conclusions?  Here’s the text from the new proposed rule:  “To provide for consideration of a range of possible futures, including potential for low-confidence, high-consequence sea level rise scenarios associated with rapid melt of land-based ice, the Department proposes adoption of projections based on a blending of projections associated with three illustrative scenarios: SSP2-4.5, SSP5-8.5 medium-confidence and SSP5-8.5 low-confidence.”

As with almost every other catastrophic climate change scenario and projection, the Climate Assessment team has used SSP5-8.5 – not just once,  but two versions of SSP5-8.5 “blended” with more sensible projections produced by SSP2-4.5. 

I’m sure that there is a procedure explaining somewhere how one scientifically “blends” projections, particularly if two of the three are considered improbable, implausible and/or outright impossible.   If you can find it, please let me know.

Normally, I would shake my head in amusement and forget it.  But in this case, everyone in New York with interests in tidal areas, including my friends and neighbors, or who pays State taxes of any sort, will be paying the price for these wildly exaggerated projections of sea level rise.

Bottom Lines:

1.  The report prepared for the New York State Energy Research and Development Authority (NYSERDA) and its projections of Sea Level Rise in NY State were touted as “Science-based State sea level rise projections”.  However, the even the projections in the updated version are poor science and do not even take into account the actual SLR seen over the last two decades, during which the SLR rate has stubbornly remained at 3 mm/yr. 

2.  The  updated NYSERDA 2014 report did not use standard procedures for its sea level rise projections, but a homespun mixture  “using  an innovative component-by-component analysis (Table 2)  that blends climate model outputs and expert judgment for  variables like ice sheet dynamics that climate models are unable to simulate.”    

3.  Worse yet, the new proposed rule under consideration,  as contained in the NY State Register, does not use the projections from the NYSERDA 2014, but instead uses the interim projections, claimed to be based on the IPCC’s AR6, in the New York State Climate Assessment.

4.  All of the projections, in the new rule,  in the NYSERDA 2014 report and in the NYS Climate Assessment require doubling and tripling of long-term SLR rates as seen at The Battery.  Such increases have not been seen in the decade since the 2014 update report and, based on the historical record,  are extremely unlikely to be seen in the near future.

5.  RCP8.5, or the newer version called  SSP2-8.5. A reasonable approach to projecting SLR in NY State, using the IPCC’s SSP2-4.5, has been polluted by “blending” in two projection sets based on the implausible, maybe impossible,  SSP5-8.5 resulting in projections that appear as fantasies.

5.  There must have been a real stickler on the NYS Climate Assessment team to force them to include the following caveat at the bottom of their SLR projections:

“Like all projections, these climate projections have uncertainty embedded within them. Sources of uncertainty include data and modeling constraints, the random nature of some parts of the climate system, and limited understanding of some physical processes. Levels of uncertainty are characterized using state-of-the-art climate models, multiple scenarios of future greenhouse gas concentrations, and recent peer-reviewed literature. Even so, the projections are not true probabilities, so the specific numbers should not be emphasized, and the potential for error should be acknowledged.”

6. Laughably, the Register entry, makes the following claim:

“4. Costs   Part 490 will not impose any costs on any entity because the regulation consists only of sea level rise projections and does not impose any standards or compliance obligations.”   

The new rule, however, literally “raises the bar”, to ridiculous heights, required for compliance with an untold number of other existing rules and regulations that mandate actions based on what will be these new official projections of Sea Level Rise, if the rule is enacted.

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Author’s Comment:

My usual Sea Level Caveats apply:  The surface of the sea is rising, it has been rising for several hundred years, slowly and inexorably. It will continue to do so until the Earth enters into yet another cool period.  Human developments on low-lying coastal land (and foolishly-built infrastructure on barrier islands) are already at risk and should undertake adaption and mitigation efforts.

The very hard-working and knowledgeable Roger Caiazza, the Pragmatic Environmentalist of New York, brought this matter to my attention — and I hope that those of you with interests in New York State will take advantage of the Comment Period to object to this new rule.

You may participate in the Public Comment process as follows:

“Written comments on the proposed rule may be submitted until 5 p.m. on April 29, 2024. Comments and requests for further information can be sent by mail to Mark Lowery, NYS DEC Office of Climate Change, 625 Broadway, Albany, NY 12233-1030 or emailed to climate.regs@dec.ny.gov.  Include “Comments on Part 490” in the subject line of the email.”

Here is the link to read the full rule proposal in the NY State Register.   The Part 490 proposal begins on Page 8.

Thanks for reading.

Note: As usual, several obvious typos and grammatical errors have been corrected on my first reading after initial publication. There were quite a few — injected by nasty little internet pixies while I distracted. kh

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