Our Unsustainable Secret: Leaded Fuel and City-Owned Fuel Tanks at Santa Monica

UPDATE, 30 MAR 2022:Elected officials in Santa Monica continue to be paralyzed and unable to do the right thing: discontinue leasing out their old tanks for leaded avgas and jet fuel sales, tanks that are decaying and well past their prime. They fear a lawsuit, and the City Attorney is only adding to their fears, by failing to identify who might file, at what venue, and citing what laws or regulations. Lacking any legitimate basis for a lawsuit, the Council is effectively being bullied into paralysis.
Here are two recent items: a letter to the editor by Joseph Schmitz, and a Facebook Post by Charles Blum.

Here’s an excellent OpEd by Alan Levenson, a resident of Sunset Park, printed in the Santa Monica Lookout. His concerns are about toxic lead, still in the aviation fuel used by recreational pilots in small planes, a situation that persists in no small part because FAA resists changes, and because local elected officials are often too intimidated by FAA to lead and serve. This is a national problem, too; there are dozens of posts under the category ‘LeadedAvGas‘. Read on…

We are all aware of the controversial airport that sits behind a fenced area in the southeast corner of Santa Monica. We have heard of the noise problems, the safety problems and the pollution. We know we were promised a great park.

What most have not heard much, if anything, about is the lead. The same lead that has been banned in auto gasoline, paint and toys is used in aviation fuel.

The leaded fuel is burned by most of the small planes that take off and buzz around over neighborhoods. The lead comes out in the exhaust and falls on people, homes, and schools below; it drops like lead at the rate of two grams per gallon. The City need not sell aviation fuel. Storing and supplying fuel is not our responsibility, and it is definitely not a sustainable business.

What most do not know is the City owns six underground tanks, three of which are 36 years old. That’s old for an underground tank; old even when not in earthquake county. The tanks sit above our aquifer; the same aquifer that has already been fouled in the past by Douglas Aircraft and leaking tanks from gas stations in years gone by. The same aquifer that supplies drinking water. Sure, the tanks are periodically checked, but accidents and failures happen.

The City is voluntarily storing and selling a known toxin. Lead has been proven to be unsafe at any level. It has been found in the blood of children around a similar airport, Reid Hillview, in San Jose, CA, at the same levels found in the children of Flint Michigan. A recent air quality study found elevated lead levels in the air around our airport and declared the airport to be the only source of airborne lead in the area.

Last November 2021 Councilmembers Brock and de la Torre proposed the City staff divest from the storage and sale of leaded fuel and the council unanimously agreed (“Santa Monica Could Join in Call for Ban on Leaded Aviation Fuel,” November 5, 2021).

Our Airport Commission also agreed. Even though we are not required to do so, the City staff has recently undertaken a project to sell unleaded fuel from one of our tanks, but our staff has not charted a known course of action to stop the sale or storage of lead in the second and older 12,000-gallon tank.

The City Attorney claims shutting out of the second tank might cause a problem in the future with the FAA or the aviators. Yet we know that in the real and now present that lead is coming out of Santa Monica Airport, exposure to lead reduces the IQ in children, and its effects are permanent.

Lead is a clear and present danger. We know the tanks sit above our aquifer. Lead is the elephant in the room and in our tanks, and that elephant must be shown the door. Santa Monica does not have to participate in this dirty business that should have ended decades ago as it was with cars, paints and toys.

Pilots and aviation businesses alike claim they too would like to get the lead out of aviation fuel. Yet while leaded fuel is available, they continue to use it. We know lead is bad. Even a little lead is bad. No lead is good. Not in our water, our air, our soil or our bodies.

No one is putting a gun to anyone’s head to sell and store leaded fuel at Santa Monica Airport.

It’s not green, it’s not sustainable, and it’s not defensible. In fact, after being asked for a clear explanation as to why we cannot get out of the fuel business we were not shown a convincing answer. We are talking lead, not bacon wrapped hot dogs on the pier. You cannot refuse or hide from airborne lead. Aviation fuel is the serious stuff of industry. Toxic to living things.

Our FAA obligations do not allow the City to ban the total use or sale of leaded fuel at the airport, but in no place do they clearly state the City must provide tanks or the City must sell fuel. It is time to retire our old tanks and get out of the leaded fuel business. It makes sense to get out of the aviation fuel business altogether.

If an aviation business wants to bring in their own newer safe and up-to-code tanks, then let them bear the costs, as well as the responsibility for the harm they are causing to those on the ground.

There comes a time to stand up for what is clearly right and reject what is not. It is wrong for a responsible and sustainable city to support and participate in the sale and storage of lead and any toxic fuels. There is no safe level of lead in our water or our air. 

We have an obligation to keep the airport open until 2029. We have no obligation to store and sell fuel until then. 

Please get out of the fuel business. Do it for the kids.

Santa Monica: The Quest for Local Control Continues

The last time the City of Santa Monica accepted FAA grant monies was in 1994. But, airport grants are not just for subsidizing the few who use the airport; they are also for imposing restrictions on the airport sponsor (in this case, the City of Santa Monica), so as to perpetuate the airport and also to compel airports to become dependent on more FAA grants. The list of restrictions, called ‘Grant Assurances’, is extensive. One of them, Grant Assurance 22, comes up time and again, used by FAA and aviation interests to confound airport sponsors and activists seeking balance or closure. 

By definition, Grant Assurances remain valid for 20 years; thus, 20-years after a grant is accepted, if an airport sponsor accepts no grants for those twenty years, they have finally earned their freedom from grant-slavery, come clean, and can theoretically regain local control of their local airport. This is what the people of Santa Monica aspired to do eight years ago, in 2014.

The Santa Monica Airport is jammed up against houses and, in fact, the spacing is so deficient residents have had lawn furniture overturned by the blast behind taxiing jets. The lead from leaded aviation fuel continues to be deposited on area homes, because FAA and the aviation industry have stonewalled the replacement of leaded aviation fuel. Indeed, in the 25-years since lead was removed from all U.S. automotive gas stations, there have been thousands of new engines built, put into new small recreational airplane designs, all centered on the consumption of leaded aviation fuel.

Activists have been fighting for health and quality of life for many decades, so it is not surprising that, when the City of Santa Monica finished their last grant obligations in 2014, a ballot measure was added to the November election seeking local control and conversion of the property to a park. The aviation lobbyists spent lots (estimates were 8-times the spending by Local Control proponents,) but they lost. The majority spoke and voter empowerment made it look like residents were going to see a park soon. It was headed that way until late January 2017, when a few City officials, fearful of dragged out legal challenges and an ongoing lack of FAA cooperation, caved to FAA’s pressure and ‘settled’ with a Consent Decree that made airport closure arguably a lot less likely.

The fight goes on. City Council met just last Tuesday, and was given a 94-page packet by City Manager David White, ‘Update on Dispensing Unleaded Fuel at SMO’. They also received 72-pages of citizen comments, all advocating for an end to leaded fuel sales, and preferring a full closure of the four underground fuel storage tanks the City owns. Included was this 3-page PDF investigating the integrity of the fuel tanks.

So, What’s With ‘Grant Assurance 22’?

Grant Assurance 22 is ten pounds of ambiguity under the headline, ‘Economic Nondiscrimination’. It has nine listed elements. Three of them are:

Grant Assurance 22a states: “It will make the airport available as an airport for public use on reasonable terms and without unjust discrimination to all types, kinds and classes of aeronautical activities, including commercial aeronautical activities offering services to the public at the airport.”

Grant Assurance 22h states: “The sponsor may establish such reasonable, and not unjustly discriminatory, conditions to be met by all users of the airport as may be necessary for the safe and efficient operation of the airport.”

Grant Assurance 22i states: “The sponsor may prohibit or limit any given type, kind or class of aeronautical use of the airport if such action is necessary for the safe operation of the airport or necessary to serve the civil aviation needs of the public.”

So, while 22a seems to imply ANY aviation activity has to be allowed without discrimination and on reasonable terms, both 22h and 22i offer exceptions, allowing specific conditions and even outright prohibitions, as needed for safety and efficiency.

Would it be a ‘reasonable term’ to NOT allow lease of an underground tank past its designed age limit? Should FAA’s view of safety include protecting area residents from lead toxin exposures? Is FAA our friend or our enemy (with us or against us)? What kind of a regulatory agency is it that leans hard with its sole authority but lacks the heart to cooperate with communities impacted by its activities?  Is this the same agency that handed off regulatory action to Boeing for the deadly 737MAX fiasco, and the same agency that grounds all tiny drones in yards to protect manned aircraft (yet is now slowly repealing rules so drones can fly low over crowds of people)? Yup, this is FAA: the U.S. aviation ‘faux-regulator’ captured to serve aviation, and working to protect industry from problematic people.

Oddly, the City Attorney is hung up on Grant Assurance 22, acting and speaking uncomfortably to question its applicability. And, unfortunately, the City Manager appears to be parroting the statements by the City Attorney. As a result, the City’s residents are being subjected to an unsafe, unhealthy perpetuation of aviation privilege that benefits a tiny elite. But these City officials are missing an important reality, so fearful they are of FAA. Both of them should ponder this: if they shut down all the tanks and an aviation lobbyist files a Part 16 complaint (against the City, claiming they are not compliant with grant assurances), their biggest penalty will be placement on the ‘Airport Noncompliance List’ and loss of grant eligibility… neither of which matter, for an airport set to close later this decade.

So, let’s close down the underground tanks. And, thank you, City of Santa Monica, for standing up to the FAA bully.

“This is obviously deliberate harassment, but the pilots tell me they can do whatever they want”

These are the words of the supervisor of the Town of Austerlitz, NY, summing up the situation — mostly recreational flyers and student pilots, flying out of Great Barrington airport [KGBR] in southwest Massachusetts, and polluting noise and toxic lead upon residents across the state line, in New York.

Incredibly, this is the case at many airports across the nation. Why? Because FAA leadership sees its role as serving excessive privilege to pilots, not serving the whole nation. And, too often, elected officials are too beholden to campaign contributions, which continue to generously come from aviation industry players, lobbyists, and pilots. So, the problems persist. Reforms are long overdue.

View the article at TheNation.com, or click here to view an aiRchive copy (2page PDF).

Let’s replace the failed DNL metric; Submit Comments by March 15th

When it comes to mitigating (or even simply recognizing!) aviation noise, FAA has a proven track record of failure. This agency serves only industry, always working to enable more operations per hour at even the busiest airports. FAA consistently fails to properly assess noise impacts, and they persist in using the failed DNL noise metric designed to guarantees any and all expansion.

There is currently a solicitation for public comments. Please go to the Federal Register webpage and submit your comments, which might include:

  • Reject FAA’s use of the DNL noise metric, the 65 dB threshold, and continued use of the Schultz Curve.
  • Reject FAA’s desire to continue to research (and thus delay reforms).
  • Demand the use of noise metrics that already exist and actually work: a good choice might be simply quantifying the number of flights per hour in peak hours and the number of flights above (or audible) per day.
  • Demand widespread selective reversion of NextGen PBN procedures to reduce today’s impacts caused by repetition and route concentration; and,
  • Demand restored local controls (ability to limit traffic levels, impose curfews, etc.) and reassignment of federal ‘noise impact oversight’ from FAA to a restored ONAC-Aviation office at EPA.

Click here to view or download the packet of documents and analysis by aiREFORM. Click here to view the Federal Register webpage, and here to submit a public comment.

Happening this Week: the Aviation Noise & Emissions Symposium

This week, aiREFORM is attending a series of presentations about aviation impacts, at the 2021 Aviation Noise & Emissions Symposium. In recent years, the annual symposium sponsored by UC Davis has been held in southern California and Florida, in late winter. This year, due to the pandemic, it was transitioned into an online symposium, using the Pheedloop virtual event platform. Organizers did a great thing: they opened registration to activists everywhere, to participate at a reasonable $25 price. As a consequence, many of the U.S. aviation impact activists are participating.

In the first two days we’ve heard four presentations. While some presenters have seemed to lack an ability to see outside the culture that delivers their industry-sourced paycheck, a few have offered great comments. Steve Alterman and Nick Miller (retired principal from HMMH) come to mind.

Those activists who did not register can still benefit. Check out the ANES-UCD website and, under the ‘About’ menu bar, open up the webpages for the 2019 and 2020 Symposia; you can then view or even download numerous PDFs with material used in the earlier events. And, the same should be posted soon after this year’s event is finished.

Some Context on ‘Noise & Emissions’

It is not clear from a cursory online investigation precisely when and how UC Davis began this series of events (we hope to add those details in the near future). But, research does show that ‘Noise & Emissions’ are at the thematic heart of what FAA was working with, as NextGen evolved nearly twenty years ago.

It starts in December 2003. That’s when Congress passed Public Law 108-176, the Vision 100–Century of Aviation Reauthorization Act. At Section 321, FAA was directed to work with NASA and others to “…conduct a study of ways to reduce aircraft noise and emissions and to increase aircraft fuel efficiency.” Noise and Emissions.

The Reauthorization included language ordering a report back to Congress, for delivery within a year. That report, authored by Ian Waitz et al at MIT, was delivered in December 2004, and at three points (p.7, p.31, and p.42) it identifies the name for the new program: Next Generation Air Transportation System, aka NGATS. It was early 2006 when FAA Administrator Marion Blakey started using the ‘NextGen’ brandname, in FAA’s 2005 Annual Performance Report.

Hard to believe, nearly 18-years later, that FAA was supposed to do good, environmentally, with the NextGen implementation. Instead, we have a program serving only industry, destroying decades-old noise abatement procedures, and imposing hugely impactful concentrated computer-flown tracks over new noise-ghettos below. Bad for community, bad for health, but good for industry, so FAA ensures it flies.

In a nutshell, NextGen is not about ‘noise and emissions’ as Congress ordered, nor is it about ‘safety or efficiency’; it is about automation, replacing human controls (pilots and controllers) with computer controls, all to accommodate heavier hub scheduling (and slightly tweaked profit margins) by the few remaining U.S. airlines. Airlines that typically operate near-monopolies at most of the U.S. commercial service airports.

For a deeper dive into how NextGen evolved and why it is failing these environmental goals, download this 2017 aiREFORM presentation (42 slide PDF, 4Mb), delivered at a Quiet Skies Puget Sound forum.

COVID’s Impact on U.S. Airports, Through December 2020

The COVID pandemic has deeply impacted the passenger aviation industry. Despite enormous (and repeated) payroll subsidies from the federal government, many people remain highly resistant to the pay-to-fly experience, most likely due to the crowding, shared air, and other dangerous conditions. This Post uses FAA’s latest ATADS data to show how the ASPM77 airports have been impacted since March 2020. The analysis goes a step further to look at the FAA’s 35 biggest commercial airports (OEP35), showing how far they had declined BEFORE the pandemic, as well as how they further declined due to COVID.

Click here to view or download the analysis.

These days, there IS such a thing as ‘a Free Lunch’

Congress has done it again, proving their bipartisan support for monied individuals and corporate wealth. Here we are, deep in a pandemic with millions facing an imminent eviction wave as well as growing food insecurity. So, why not add language to a temporary aid package, that allows 3-martini lunches (and other business meal expenses) to be paid fully (as in 100%!) by the taxpayers?! The outgoing President wants it (some of those meals will be procured at his businesses); so, WHY NOT? (see article at Boston Globe, or PDF copy here)

This has been a grueling year. It seems that not a minute passes without yet one more surreal news item or troubling tweet. Somehow, a more hopeful core within makes me ‘hope’ this is a fake news story. But, it likely is not. It is just like the pattern of corporate-welfare and capital-welfare we have so long seen within aviation. Two examples:

  1. federal tax rules for accelerated depreciation and bonus depreciation coddle concentrated wealth, enticing those with larger income tax bills to instead spend those taxes buying jets and helicopters AT PUBLIC EXPENSE.
  2. lobbyists have pushed legislation, passed in so many states, that waives sales taxes for aviation-related expenses such as maintenance, creating the absurd reality that a minimum-wage parent with a beater car pays sales tax for an oil change, but the owner of a small plane (mostly older, mostly white, mostly male, and flown mostly recreationally) pays ZERO sales tax as a privilege.

As Bob Dylan would sing, The Times They Are A-Changin’. Conditions are getting worse in the U.S., economically, for those who do not have money reserves. Yet, the same duopoly that panders to aviation and the White House holds the majority hostage while serving out more for the most elite wealth. Will our electeds at any level come around to taking care of people first, before money? Reforming aviation is a great place to start.

Learn More? ..see ‘SubsidizedAviation’

[aiRchive] A Bicameral Letter to FAA Administrator Steve Dickson

The end of 2019 is looking far better than the start of this very long year.

A few days before Christmas, eighteen elected representatives, from both the Senate and the House, sent the following letter to FAA Adminsitrator Stephen Dickson:

Click on the image below for a scrollable view of the international Press Release; the PDF file may be downloaded.

The letter makes reference to the 41-page Audit Report done by the DoT Inspector General and published last August (click here for a PDF copy, archived at page two of this Post).

An aiREFORM Analysis

Here are a few quick observations:

  • The Bicameral letter is excellent, but has one incorrect point in paragraph #2, where it repeats the oft-declared propaganda by FAA that Metroplex was introduced “…in order to make airspace more efficient.” FAA’s true reason for Metroplex was to achieve a giveaway for the airlines; they used Metroplex to do a wholesale removal of all previously existing noise mitigation procedures, so the airlines would no longer be encumbered with the ‘nuisance’ of having to reduce impacts below.
  • Again, Metroplex is NOT about efficiency. If Metroplex was about improving efficiency, would we not expect FAA to be deeply concerned about the gross inefficiencies of flying more and more passengers on longer overall trips, via major airline hubs? Would we not see FAA advocating for ticket prices (and fees) proportional to total direct-miles flown, and advocating for a steep aviation carbon tax?
  • True efficiency would be accomplished by ensuring the passengers are able to fly direct, one-hop flights from trip origin to trip destination. But, it behooves FAA and industry players to fly more passengers indirectly, via hub airports, as doing so artificially inflates enplanements, falsely suggesting a booming industry. And, more enplanements translates to more airport passenger fees, an attractive revenue generator for airport authorities like Port of Seattle and MassPort. This is a system rigged toward concentration, imposing a noise/health cost on local communities, and also undermining the viability of other airports within a few hundred miles of the emerging super-Hubs.
  • The Senators and Representatives are hopeful that FAA will start serving ‘We The People’, not just industry players. But FAA has a long history of arrogance, indifference, and aversion to accountability. This is the same ‘regulator’ that essentially let Boeing self-regulate the 737 MAX design that killed 346 in two horrific crashes, and was the last national regulator to ground this dangerous design.

So, what a year, right? So much has been revealed. So many individuals have persisted in their activism. Maybe, just maybe, in the coming New Year, we can see more growth in the support needed from those we elected to serve?

To serve ‘We the People’, not to serve the aviation corporatocracy.

[ai-RCHIVE] Four Versions of FAA Advisory Circular 91-36

Here’s an example of abusive pilots, that also shows how FAA is a captured federal regulator actually enabling this type of abuse.

Fort Devens is a historic U.S. Army facility in the towns of Ayer and Shirley, roughly 25-miles west of Boston. Years ago, the Moore Army Air Field was closed. According to Wikipedia, part of the land then became a hospital facility, aimed primarily at serving specialized and mental health needs for prisoners.

Back in the early 1970’s, coincident with ‘Earth Day’ and the wave of citizen empowerment toward improving and protecting the environment, FAA was nudged into creating an ‘Advisory Circular’ about small airplane noise. The advisory circulars are not binding or regulatory, but they do spell out what FAA asks the pilot community to do, toward achieving certain objectives. This is how FAA treats pilots: ‘pardon me, would you please try this?’, like royalty. If pilots do not conform to the ‘advice’ contained within an advisory circular, eventually FAA can become compelled to issue actual regulations. Now, if FAA also chose to enforce those regulations, we might achieve a nice balance, between the right of the pilot community to use their aircraft, and the rights of the non-pilot community (aka, all of us residents) to enjoy our homes and yards without excessive noise and aviation air pollution.

Roughly a decade ago, residents around Ayer prevailed in a nuisance lawsuit filed against a group of pilots. Ever since, there has been an extraordinary concentration of low-level small-plane flight activity over the homes of the residents who won that legal action. When these residents complain to FAA, to MassPort (the airport authority), or anyone, they get nothing but deadends.

Check out this disturbing example, posted on Facebook.

Now, about that ‘Advisory Circular’. In the 46-years since it was first posted in 1972, it has been updated three times. The updates are generally unsubstantial, as you can see for yourself. Here are links to archived copies of all four versions of FAA’s Advisory Circular 91-36, ‘VFR Flight Near Noise-Sensitive Areas’. Each version is 2-pages, with minor changes as the Advisory Circular evolved. Version ‘91-36B‘ was signed off in 1982, version ‘91-36C‘ appeared in 1984, and version ‘91-36D‘ (the current version) was signed off in 2004.

Frankly, these four versions of Advisory Circular 91-36 show FAA’s ‘milquetoaste approach’ to NOT managing aviation impacts. FAA has made it clear to rogue operators like this one near Boston: they may bully with impunity, knowing FAA will not impair this perceived ‘right’. The impacts that FAA recognized in 1972 have persisted because FAA refuses to serve and fails to evolve. And so, across the nation, for two generations now, residents have complained and been ignored by an agency that serves only the industry it is supposed to be regulating.

Pine Island Glacier: the latest example of rapidly melting polar ice that will eventually flood major airports

Ecowatch published an informative article about a huge iceberg, roughly 115 square miles, that has calved off of the Pine Island Glacier. The article cites an interesting series of posts by Stef Lhermitte discussing a large new iceberg, designated B-46, which is rapidly disintegrating as it drifts toward the Pacific Ocean.

The series of posts includes a GIF slideshow showing annual sea-ice extent at the Pine Island Glacier. Here is a scrollable PDF showing a series of screencaps taken from the GIF slideshow, with images at roughly a 5-year interval from 1975 to 2018 (depending on what years had available images). The sea ice extent for each year is indicated by a color-coded thick line; over time, this line progresses upward, exposing more of the seawater below. In the background of all images, the satellite image appears to be current, as taken on 10/30/2018.

Click on the image below for a scrollable view; the PDF file may be downloaded.

Overall, this series of images shows a pronounced decline in sea-ice coverage. Within the images, you will also notice that there were a few years, ending in 2013, where sea-ice cover was expanding. Since 2013, the melting/calving has been precipitous. Bear in mind, the polar regions are in total darkness for months each year, and it may take years for new meltwater to mix with the seawater below. Thus, massive ice melting may cause an easily frozen freshwater lens to sit atop the seawater. This will create an illusion of expanding sea-ice extent for a few winters. But, eventually, once the excessive freshwater becomes mixed, or as ambient air temperatures continue to increase, the expanded ice that peaked in 2013 will become just a distant memory.

Putting this in a Geographic Context

Here is an excerpt from Wikipedia, describing this specific glacier:

Pine Island Glacier (PIG) is a large ice stream, and the fastest melting glacier in Antarctica, responsible for about 25% of Antarctica’s ice loss.[3] The glacier ice streams flow west-northwest along the south side of the Hudson Mountains into Pine Island Bay, Amundsen Sea, Antarctica. It was mapped by the United States Geological Survey (USGS) from surveys and United States Navy (USN) air photos, 1960–66, and named by the Advisory Committee on Antarctic Names (US-ACAN) in association with Pine Island Bay.[1][4]

The area drained by Pine Island Glacier comprises about 10% of the West Antarctic Ice Sheet.[5] Satellite measurements have shown that the Pine Island Glacier Basin has a greater net contribution of ice to the sea than any other ice drainage basin in the world and this has increased due to recent acceleration of the ice stream.

Here are a pair of images, showing Pine Island Glacier’s location on Antarctica, and showing the seas that surround Antarctica, connecting it to the extreme southern oceans.

What Does this Suggest for Our Global Future, and for Aviation?

The rate of calving in recent years is disturbing, and reflects a harsh reality: if our ever-expanding over-consumption of fossil fuels is not reined in, and we continue to see 2- or 3- ppm annual increases in average atmospheric CO2 concentrations (see Keeling Curve), we can expect collapse of these polar glaciers and large-scale sea-rise. Hundreds of the busiest airports across the globe will become underwater. Homes for more than a billion people will also become uninhabitable, under sea-rise. Displaced people will need to find new homes, and that situation will result in global conflict and likely massive human depopulation.

Would it not be a good idea to immediately impose policies that strongly disincentivize excessive and arbitrary use of aviation?

A Closing Image: Accelerated Melting is Likely

Below is a different perspective, rotated, but showing the recession of the glacier (roughly from left to right) and how it compares to actual shorelines beneath. The areas of ice over water are designated as the ‘northern ice shelf’ and ‘southern ice shelf’. Over land, colors appear to show ice flow rates using a spectrum, with red being fast, yellow being moderate, and blue being slow. A major concern among scientists who study polar ice loss and related sea-level rise is that loss of sea-ice eventually removes an important ‘plug’ that holds back glacial ice over land; kind of like eroding the footing out from under a bridge pier. In other words, in this example, the fear is that once the Pine Island Glacier recedes beyond the base of the SW tributary and the southern ice shelf is nearly gone, ice flow from the SW tributary will rapidly accelerate, which in turn will rapidly accelerate global sea-level rise.

It would seem to be very foolish, to continue to ignore this evidence.