I am updating this series due to: 1) a new PSMSL release of data near the end of July, 2) updated analysis of sea level change (SLC) which manifests itself as sea level fall (SLF), 3) a new understanding of SLF graphing, and 4) to inform readers that I have added a new Cryosphere location to my SLC software.
The new Cryosphere location is the Himalayas:
"The Himalayan Mountains are home to the highest peak in Mount Everest at 29,029 feet, but also to the third largest deposit of ice and snow in the world, after Antarctica and the Arctic. Now the first complete study of this remote region reveals that its glaciers lost billions of tons of ice—equivalent to more than a vertical foot and half of ice each year—from 2000 to 2016."(National Geographic). Readers may wonder why that Cryosphere location had not been included earlier on.
Even though this is a large source for SLF, it does not impact as many tide gauge stations as smaller ice deposits in other Cryosphere locations do (see e.g. Proof of Concept, 2, 3, 4, 5, 6, 7, 8, 9, 10; The Evolution and Migration of Sea Level Hinge Points, 2).
Nevertheless, the "Glaciers of the Tibet Autonomous Region" and China's other glaciers seem to influence China's sea level change (SLC) in zone 1311. [UPDATE zone 1310 has a lot of glaciers according to GLIMS and is about 1,200 km from zone 1311's China coastline]
That is the only zone where China's tide gauge stations show a little SLF, and it is an important area because the country that is the world's number one international container shipping power is impacted.
So, I checked out the area for sources:
"Millions of people each year are drawn to Baishui’s frosty beauty on the southeastern edge of the Third Pole – a region in Central Asia with the world’s third-largest store of ice after Antarctica and Greenland that is roughly the size of Texas and New Mexico combined."(Phys Org). The focus on seaports naturally involves China because they have the busiest cargo container ship seaports.
So, the fact that some of their seaports are in a zone that has SLF while the other zones where China seaports are located have sea level rise (SLR) complicates their response to SLC.
The new Cryosphere location needed to be included because analysis of SLF is more complicated than analysis of SLR.
For one thing, SLF is not subject to intuition as SLR is (blame the common bathtub model belief for that).
II. Why Be Concerned?
Of course it seems like a catastrophe when climate change causes damage which leads to court cases that can cost someone some money.
Such costs can't be avoided forever, so Who will pay? one way or another is increasingly discussed (Climate liability is on the rise. Here's what it looks like).
"Naturally" that discussion brings on episodes of denialism.
For example, the "it's a hoax so let's not think too much about it" meme:
"The Trump administration plans to leave out 'worst case scenario' projections from the National Climate Assessment, a multi-agency report published every four years that presents scientific research on the effects of the climate crisis. According to the New York Times, Director of the U.S. Geological Survey (USGS) James Reilly has directed the report to only provide projections through 2040, which will not show the devastation brought about by climate change into the next century."(Science Denied as Trump Orders Halt on Prescience). Official-dumb is afraid to face the big story.
There is also the "since we can't predict exactly what will happen in a hundred years, let's predict what will happen in a thousand years" meme:
"The Greenland Ice Sheet holds 7.2 m of sea level equivalent and in recent decades, rising temperatures have led to accelerated mass loss. Current ice margin recession is led by the retreat of outlet glaciers, large rivers of ice ending in narrow fjords that drain the interior. We pair an outlet glacier – resolving ice sheet model with a comprehensive uncertainty quantification to estimate Greenland’s contribution to sea level over the next millennium. We find that Greenland could contribute 5 to 33 cm to sea level by 2100, with discharge from outlet glaciers contributing 8 to 45% of total mass loss. Our analysis shows that uncertainties in projecting mass loss are dominated by uncertainties in climate scenarios and surface processes, whereas uncertainties in calving and frontal melt play a minor role. We project that Greenland will very likely become ice free within a millennium without substantial reductions in greenhouse gas emissions."(Contribution of the Greenland Ice Sheet to sea level). The song "In the year 2525" comes to mind.
But seaports can't wait a millennium or even a century because they had better be working on it starting "yesterday" (Seaports need a plan for weathering climate change).
They could be facing a crippling sea level change scenario:
"The authors write that, for planning purposes, it would be prudent to use scenarios that anticipate 6.5 feet of sea level rise by the end of the 21st Century—more than double the likely upper limit put forward by the Intergovernmental Panel on Climate Change."(Inside Climate News, emphasis added). The graphs in the appendices to this post (links below) are based on that general amount, but nether SLF nor SLR are uniform like in a bathtub, so that figure varies with location.
Several competent scientists say it could be much quicker (A Paper From Hansen et al. Is Now Open For Discussion, 2, 3).
That is why I use local tide gauge station data rather than the lame "one size fits all" dicta (The Bathtub Model Doesn't Hold Water, 2, 3, 4, 5).
Seaport authorities have to realize the conditions they face, not what others face.
III. Why Focus on Seaports?
We don't hear enough discussion about seaports even though they are obviously going to bear the brunt of SLC, whether they face SLC in the form of SLR or SLF (Seaports With Sea Level Change, 2, 3).
They face extinction (The Extinction of Robust Sea Ports, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11).
Civilization as we know it is akin to ancient Phoenicia in that regard (The Extinction of Robust Sea Ports - 3).
Keep a keen eye on seaports.
IV. Analysis of SLF
A. How To
There is a process that saves time and effort when analyzing SLF.
The first thing to do is isolate any aberrant PSMSL measurements by reading their data concerning the tide gauge stations at issue (rare errors do happen and the PSMSL folk mark them).
Next, since SLF only happens as a result of a tide gauge station being within about 2,000 km (within the "hinge point") of a Cryosphere location such as an ice sheet or a large glacial area, check if an ice field is within that range (The World According To Measurements - 5).
Pseudo SLF (slow land uplift) is a suspect if there is no Cryosphere location close enough to the tide gauge station to cause SLF readings on the tide gauge (earthquakes can cause abrupt uplift, so watch for land level changes too).
In the absence of a valid cause for SLF records, I tend to not use that tide gauge station's records any longer.
B. A New Graph Concept
Remember first that loss of large volumes of ice, and therefore their gravitational power, in the Cryosphere locations are the prime cause of SLF.
Also remember that the ice mass is decreasing at the ice location, so the gravitational pull is also decreasing along with it (Fig. 1 shows the roller coaster effect caused by the changing ice mass loss).
Thus, in the future all Cryosphere locations will cease to have any gravitational power over the ocean near them when their ice mass becomes inconsequential.
Therefore, the last remaining sources of SLR (e.g. Greenland or Antarctica) will reclaim control of SLC dynamics, and reform all less powerful SLF areas, far away.
By "remaining sources of SLR" I mean those Cryosphere locations which still have enough ice mass to cause the return of SLR readings at tide gauge stations that at one time had SLF readings.
The graphs in the appendices show this new concept in the form of a curve or similar type of change in the SLF line as it turns back into an SLR line.
They graphs do so to indicate that particular SLC event (SLF turns into SLR) ... in terms of when it is projected to happen.
This simply means that the ice mass loss is so large over time that not enough ice remains to have enough gravity to pull water toward the coastline of the land the Cryosphere location is (or was) on.
Since this is a new graph concept, the graph appendices have the SLF location graphs first, then the SLR locations below them.
Today's post contains the usual extensive list of seaports around the globe, along with tide gauge station data that bear upon the sea level at those seaports.
Additionally, SLC values are listed along with distances to Cryosphere locations from the port area.
In SLF scenarios the distance to the relevant Cryosphere location should be less than or equal to ~2,000 km.
Links to Appendices
|Appendix: A - C||Appendix: A - C||Graphs A - C|
|Appendix: D - G||Appendix: D - G||Graphs D - G|
|Appendix: H - L||Appendix: H - L||Graphs H - L|
|Appendix: M - O||Appendix: M - O||Graphs M - O|
|Appendix: P - T||Appendix: P - T||Graphs P - T|
|Appendix: U - Z||Appendix: U -Z||Graphs U -Z|
VI. Closing Comments
Like the past, we make the future by what we do today.
This post is a public service of Dredd Blog.
The next post in this series is here, the previous post in this series is here.