Tipping point for Antarctic

[Richard Kerver]

Evidence of Antarctic glacier's tipping point confirmed for first time

• Pine Island Glacier is a region of fast-flowing ice draining an area of West Antarctica approximately two thirds the size of the UK. The glacier is a particular cause for concern as it is losing more ice than any other glacier in Antarctica.
  
• Dr. Rosier explained: "The potential for this region to cross a tipping point has been raised in the past, but our study is the first to confirm that Pine Island Glacier does indeed cross these critical thresholds.
  
• "But the findings of this study also concern me. Should the glacier enter unstable irreversible retreat, the impact on sea level could be measured in metres, and as this study shows, once the retreat starts it might be impossible to halt it."
  
• This could lead to the collapse of the entire West Antarctic Ice Sheet, which contains enough ice to raise global sea level by over three metres.
  

In my opinion, given the course of recent human history, and despite recent political events suggesting optimism, IPCC worse case scenarios for sea level rise are the most likely.  In other words, prepare now for a 3 meter rise (10 feet).  

[Richard Kerver]

Here is NOAA's visualizer:  https://coast.noaa.gov/digitalcoast/tools/slr.html

[Richard Kerver]

First-Ever Observations From Under Antarctica’s ‘Doomsday Glacier’ Are Bad News

• Glaciers all over Antarctica are in trouble as ice there rapidly melts. There’s no Antarctic glacier whose fate is more consequential for our future than the Thwaites Glacier, and new research shows that things aren’t looking good for it.
  
• A new study published in Science Advances on Friday presents the first-ever direct observations of what’s going under the infamous ice shelf, including the temperature and salinity of the water that’s flowing under it as well as the strength of the current.
  
• Given that it’s often called the “doomsday glacier,” that’s particularly ominous.
  
• captured data showing that warm water—warm for a glacier, at up to 33.89 degrees Fahrenheit (1.05 degrees Celsius)—is swirling around the glacier’s crucial “pinning points,” or the points of contact where the ice shelf meets the bedrock that holds it in place. This warm water is melting away these crucial holds, making room for cracks and troughs in ice that can make the shelf all the more unstable.
  
• Scientists previously thought this part of the glacier was protected from the bay’s currents by a thick underwater ridge. But it seems they were wrong—the findings indicate it’s flowing into the trough freely. That closely links its fate to the bay more than climate models currently account for. 
• “Thwaites is really being attacked by the ocean from all sides,” said Graham. All this has very serious consequences for those living along the coast. Thwaites Glacier’s collapse would raise sea levels by 1.5 to 3 feet (0.5 to 0.9 meters), and could also trigger an even worse chain of events because it could initiate the collapse of another nearby imperiled ice shelf, the Pine Island Glacier. Together, these shelves act as a braking mechanism on land ice that, if released into the open waters, could push seas up to 10 feet (3.1 meters), overwhelming coastal cities around the world. 
• The study illustrates the importance of climate adaptation measures, including weighing the potential benefits of having communities retreat away from coasts.
• attached is a pictograph from the Science Advances article, depth gage from under the glacier, clearly showing the warm water flowing freely and melting the entire ice shelf from below

In last missive, provided:   NOAA's visualizer:  https://coast.noaa.gov/digitalcoast/tools/slr.html

.... which shows Boston nearly completely under water at 10 ft.  Note that the visualizer max is 10 ft, which must now be understood to be the minimum sea level rise given the emerging data this year.  When I suggested "prepare now", I meant that all the climate resilience and adaptation funding in Massachusetts is right now - the grants are now.  This latest data suggests all of it is a too little too late response, like in Worcester's recently published resilience plan.  No way to save Boston, no matter how many billions are thrown at it.  Best to abandon Boston and migrate the population to higher ground.  Meaning Worcester should be preparing for a large influx of climate refugees, from our own coasts.  And the shutdown of global commerce, as no way that survives the devastation of ports world-wide. 

On Sat, Apr 3, 2021 at 4:20 PM Richard Kerver <rke...@gmail.com> wrote:

[Richard Kerver]

This is the story of the year, as Science + Biden + GND races the ticking clock to avert the worst, which now....  TheGuardian: Sea levels are going to rise by at least 20ft. We can do something about it.  FYI, I've asked this question of the experts for the last twenty years.  As I attended various conferences at WPI, ClarkU, HC, etc:  "What's your prediction for sea level rise?"  Its a complex question as anyone who knows the science knows.  Answers were mostly in ranges, like:  "between one and a hundred feet".  A great deal of uncertainty.  But as of 2020, the models are better, the data is better and these recent reports give us an increasingly accurate prediction.  So my answer based on all this is "between 10 and 20 feet".  NOAA needs to modify its sea rise viewer.  From the articles:

• As a result, average sea levels around the world are now all but certain to rise by at least 20 to 30 feet. That’s enough to put large parts of many coastal cities, home to hundreds of millions of people, under water.
  
• But if seas rise 20 feet or more over the next 100 to 200 years — which is our current trajectory – the outlook is grim. In that scenario, there could be two feet of sea level rise by 2040, three feet by 2050, and much more to come.
  
• To minimize future sea level rise, we need to lower that amount from today’s 417 parts per million towards the 280 ppm that prevailed before industrialization.
  
• What’s insufficiently appreciated is that most of this warming – over 93% – has transferred to the oceans and significantly warmed the upper 2,000 feet. This is accelerating polar ice melt and global sea level rise and will continue to do so for centuries.
  
•  After 1930, as ocean warming and water expansion kicked in, the rate of sea level rise doubled and doubled again, reaching 3.1mm a year by 1990. Since then, as ever-warmer oceans have driven polar ice melt, the rate of sea level rise has quickened further. Today, oceans are rising 6 mm a year (over two inches a decade), and this pace will continue to dramatically accelerate.
  
• Sea level rise of 8ft would be catastrophic. Absent extensive and very expensive adaptation measures, it would put much of New York and Washington DC, Shanghai and Bangkok, Lagos, Alexandria and countless other coastal cities underwater. It would submerge south Florida.
  
• Today, accelerating ice melt in Greenland and Antarctica are almost certainly the beginning of a new pulse of rapid sea level rise.
  
• Rather than building more in low-lying regions and spending public money on coastal defenses that are bound to fail, we should prepare to assist the eventual relocation of people and infrastructure from the most threatened areas (and clean the land before inundation).
  

• Harold R Wanless, a professor of geography and regional studies at University of Miami, was one of Politico’s 50 “visionaries who are transforming American politics” in 2016.
  

On Sat, Apr 10, 2021 at 6:44 PM KarenJean North <kno...@me.com> wrote:

Oh my this is scary- did a climate webinar today - thinking on verge of pAradimn 
Shift to get youth taking action 

[Richard Kerver]

It is not unreasonable to expect 3 feet of sea level rise by 2050, the date Massachusetts has sent to achieve net-zero.  Here is Boston at 3 feet:

https://coast.noaa.gov/digitalcoast/tools/slr.html

The concept of the organization "Tataessetaki" is a regional land trust spread through the various farming communities of central Massachusetts.  A land trust which conserves all three classes of trust:  1> farmland, for farming, 2> wildlands set-aside for preservation of ecosystems, and 3> community, for housing.  It envisions a small-house village in the middle of a farm, surrounded by wildlands.  Such a Trust does not yet exist, but could, with the right kind of planning & support.  Base Trust would be wildlands with ground lease extended to farmers and householders.

In this context, it is a last-ditch effort to preserve land in the face of what must be expected, a migration for coastal areas prone to increased flooding.  Climate refugees just don't rebuild their lives of way too much, but downsize, including the size of houses, from an average of 2000 sq ft to 200 sq ft.  And then do intensive biodynamic farming for community food security.  Decoupled from consumerism.