Where does six feet come from?
It seems very suspicious. It contradicts NOAA Sea Level Trends data of tide gauge measurements, going back to 1930 and sometimes earlier. According to the map, in almost all places in US the projected sea level trend is no more than 1-1.5 feet by 2100:
What is more, the trend is clearly linear from the start of the measurement. The trend hasn't changed in recent years.
For example, see data from the gauge in Sandy Hook, New Jersey, from 1932: "The relative sea level trend is 4.09 millimeters/year with a 95% confidence interval of +/- 0.2 mm/yr based on monthly mean sea level data from 1932 to 2018 which is equivalent to a change of 1.34 feet in 100 years."
Gauge in Lewes, Delaware, data from 1919: "The relative sea level trend is 3.48 millimeters/year with a 95% confidence interval of +/- 0.23 mm/yr based on monthly mean sea level data from 1919 to 2018 which is equivalent to a change of 1.14 feet in 100 years."
The issue with Thwaites Glacier is it has a tapered edge that generally resists thawing, but that widens out to a huge contact surface area once erosion by salt water progresses.
This glacier alone will cause a global sea level rise of three feet.
 - https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/201...
Where did you get that information? This source from Wikipedia says it would cause a rise of 4 inches:
At the beginning of 2020, researchers from the ITGC took measurements to develop scenarios for the future of the glacier and to predict the time frame for a possible collapse: The erosion of the glacier by warmed ocean water seems to be stronger than expected. The researchers noted with concern, that at the baseline of the glacier, the temperature of the water is already more than two degrees above freezing point. They confirm thawing of the Thwaites glacier contributes about four percent of global sea-level rise. The collapse of this glacier alone would raise the sea level by about 65 centimetres (25 inches).
Your quote says 4% of global sea level rise from this one glacier, not 4" - it says 25" at the end there.
 Anyway to be more specific, there's a single Antarctic glacier with enough water to cause 0.5 meters of sea level rise, and a recent measurement shows it will melt in "decades, possibly more than a century." https://www.bbc.com/news/science-environment-51097309
See also https://tamino.wordpress.com/2019/10/14/sea-level-accelerati...
I hope you'll forgive the reader for interpreting this as them positing that the trend is linear.
> Although the trend may vary with the end year, there is no statistically significant difference between the calculated trends if their 95% confidence intervals overlap. Therefore, the most recent calculated trend is not necessarily more accurate than the previous trends; it is merely a little more precise. If several recent years have anomalously high or low water levels, the values may actually move slightly away from the true long-term linear trend.
Where a SLR of 2m by 2100 is reported as an extreme scenario, presumably (but I can't find it in the text) with very low confidence. They give the following definition of the reasons for the low confidence rating, though: "Inconclusive evidence (limited sources, extrapolations, inconsistent findings, poor documentation and/or methods not tested, etc.), disagreement or lack of opinions among experts".
2m in sea level rise is roughly the current "intermediate" scenario, which would happen if the world made immediate and large reductions in CO2 emissions. That is, we're on track to be worse than that now.
Since I've seen this exact error on HN before (don't recall if it was you who made it or not): do you understand that giving the 2018 sea level rate change as "1.34 feet per 100 years" is NOT a prediction that the sea level will change 1.34 feet over the next hundred years?
What is the basis for 2 m prediction?
> giving the 2018 sea level rate change as "1.34 feet per 100 years" is NOT a prediction that the sea level will change 1.34 feet over the next hundred years?
Global 0.3 m rise is among the possible scenarios.¹ And this scenario is consistent with historical measurements. Also note that CO2 level has been rising for the last 60 years. Sea level trend stayed the same compared to the period before industrial CO2 rise.
It looks like their analysis may have been skewed somewhat by the fracking boom in America's oil shale country. That may explain the otherwise odd migration pattern into sparsely populated areas running up from Texas through the center of the country.
Isn't it extremely ironic, given the topic hand?
Look at the people displaced by fires in the North Bay who now can't afford to live anywhere nearby.
It's not clear whether those companies would invest in dikes or just move somewhere else, but I'd assume the former.
 https://msc.fema.gov/portal/search and search for "1 Hacker Way, Menlo Park, CA", "1600 Amphitheatre Parkway, Mountain View, CA" or "1170 Bordeaux drive, Sunnyvale, CA"
That said I have basically the same question. Why are cities not getting above average immigration? You noticed Chicago, I noticed Buffalo and Rochester, which are the #2 and #3 largest cities in NY.
Many may end up moving to the suburbs in the Midwest, where the model shows a larger-than-average influx of migrants compared to historic trends.
So, it is really showing places that have not historically had a lot of people moving in.
If rural western Kentucky gets 2 climate migrants and Chicago gets 100, this may represent a much greater increase in Kentucky migration rates than Chicago migration rates.
It may be that the extra migration doesn't impact that average comparted to less populous counties.
So it presents a more alarming picture than one would imagine.
For almost all of coastal California, you don't have to go very far inland until you're way above sea level. LA looks flat, but go three blocks inland from the beach in Venice and you're up a few meters. The California coast is the shelf of a mountain range.
Florida, though, does have real problems. Most of the state is barely above sea level. And Miami is on permeable rock; sea walls won't help.
Food insecurity, resource conflicts, extreme weather events, and a global migrant crisis (caused by the first two issues) will be. Unlike sea level rise, all it takes is one bad year to spark these.
Also, Miami and Venice are on borrowed time.
I feel confident that in the next 80 years we'll manage to figure out how to build some 6ft tall levees.
There will be little climate migration. People like living near the coast.
About one third of the Netherlands lies below sea level, with the lowest point being 22 feet (6.7 meters) below sea level. Doesn't make for much of a post-apocalyptic visual - act now or end up like the Netherlands.
That was 1969, or less than 70 years.
Poor reading comprehension on my part. You are, of course, correct.
The sea level rise is due to more water in the ocean. That doesn't translate into more water in a river, because water doesn't flow uphill.
However, one could argue there would be an increase in precipitation as less water is trapped in ice but that doesn't seem to be what many people are predicting. I say all this with the caveat that I am not very well read up on the science of all of this, I'm just going by what I have read in articles and what not.
I learned that ice has a (slightly) lower density than water, hence it usually floats. I was convinced that submerged ice is doing so because of an additional weight on top of it (above-water ice pack).
Maybe there is also ice that is submerged without this extra weight, but then its density should be lower than water.
Either way, I don't see how submerged ice could take up exactly the same space when melted. If it has a different density, it should change in volume (elementary physics).
When that ice melts, it still weighs the same amount and fills exactly the amount of space that it was displacing. In other words, it fits perfectly in the space in the water that it was already occupying.
So floating ice that melts (above or below the water) doesn't change sea levels at all.
Only melting ice that is currently supported by land will increase sea level.
Liquid water is notorious for having almost no thermal expansion, but the little bit it does have will be multiplied by the volume of the ocean, then divided by the surface area of the ocean, yielding the rough vertical rise.
Maybe in otherwise dry areas, but I doubt it.
In the 1800s, Chicago was lifted up from nearly being at the same level as Lake Michigan: https://en.m.wikipedia.org/wiki/Raising_of_Chicago
I don't see this happening across the entire coastline of the US or (even less likely) along the shores of affected tributaries.
Just look at coastal real estate. Buyers and lenders would have to be colossal fools to pay such premiums to be waterfront. Even Obama just plunked down 12M on a waterfront mansion on the low lying island of MV.
Much waterfront property is _already_ vulnerable (and expensive to insure) today, regardless of whether you believe in consensus climate science, due to storms and flooding in current climatic conditions. That house by the ocean is going to destroyed at some point, the only question is when and how.
I have not yet, however, seen any such research on consensus for the effects of climate change. Is there a large, documented consensus on any estimate of sea level raise?
My point was that real estate market prices are much more heavily influenced by current conditions, and current demand, rather than hypothetical future conditions. The price elasticity of demand has little to do with whether the buyer believes that the property will flood in future decades due to climate change. Someone who wants a beachfront mansion is probably going to buy it for close to the same price whether or not s/he believe it will still be there in 50 years, just as s/he might buy an expensive car that will similarly degrade and need expensive maintenance exceeding the original purchase price over time.
If we are talking about the US then there's government flood insurance.
If you still believed what was once the consensus, you would believe in some crazy stuff. Science is skeptism of the consensus, not the other way around.
As long as the skepticism is evidence based, of course.
Real estate is about the closest thing to putting your money where your mouth is as far as climate change goes and the people have spoken - the coasts are still the most valuable and desirable places to live.
I would definitely buy coast property today because this won't be a significant problem in my lifetime. I'd buy from coast again when it becomes a significant problem, just that the coast location would be different of course.
What do you think happens in that 100 years? I assume this would be a near linear progression. That means current waterfront has about 10-20 years, not 100.
The note under map says: Blue indicates counties where flooding will displace residents if sea levels rise by six feet by 2100. Counties in shades of pink and red will see higher-than-average migration, with the darker shades representing larger population increases.
So it only means people will likely migrate to other areas, not that the blue places will be totally underwater by 2100.
Got me wondering though, are you really a climate change skeptic? I mean climate change is something as obvious as gravity, we have all the data to support it, we can directly observe it etc. I find it hard for a sane people to question it, really. I mean I understand how someone can be skeptical about "man made climate change" which is something open to debate, but climate change itself isn't really open to debate.
I have a background in financial modeling, using exponentially more observations, in a less chaotic system, with participants betting on the models with real dollars. It makes climate change models look like simplistic toys, which most are.
There is NO consequence of being wrong with a climate model, no shame, and there's a high degree of survivorship bias. Climate models that have been right, have been right for the wrong reasons. Climate models that have been wrong (most) are long forgotten and never discussed. New models come out all the time to hype fears for events that prior models predicted would be happening now (and aren't).
The question isn't does the climate change, the question is do we understand it at all.
- Everyone already knows rising sea levels will cause more flooding and property damage.
- What's new here is that they make attempts to estimate displaced populations and where they will migrate.
- The reception of American climate migrants will not be evenly distributed. Cities nowhere near the coast will be impacted by climate change.