[rbt]

I don't think L.A. can address declining water supplies in the same fashion.

Though both will find that the solutions (which will be delivered, at least in part) will drive up the cost-of-living.

A 5GW off-shore windfarm + off-shore mechanical desalination would solve all Southern California urban water issues for under $30B; run it when the wind blows and pump clean water up hills to existing storage facilities.

Doing desalination 1 mile off-shore eliminates nearly all of the salt concerns as there is both significantly less life to impact and it could be scattered at across a very large volume (various depths and area)

 

[Transportfan]

And Manhattan will be underwater in a few decades due to climate change

They said that decades ago already.

 

[Northern Light]

They said that decades ago already.

So that you're aware, NYC is moving to build seagates and large landform berm to prevent flooding in surge events.

That's already a real project (though not yet under construction).

That said, there's loud concerns being expressed, that the over $119,000,000,000 USD (that's 119 billion) won't be enough.

The $119 Billion Sea Wall That Could Defend New York … or Not (Published 2020)

A six-mile-long barrier would help protect the city from floodwaters during fierce storms like Sandy, but critics say rising seas make the option inadequate.

www.nytimes.com

That solution, if effective at all, will only help with surges, not high tides or general ocean level rise.

It may also trap sewage leaving NY'ers surrounded by their own excrement.

There are separate projects being discussed for landlforms, wetlands and other solutions.

But NYC is facing serious issues.

Will it survive? Of course; too much money tied up there not to defend a good chunk of it from nature.

But the defense will likely increase the cost-of-living, and probably still dislocate at least thousands and maybe over 100,000 New Yorkers.

L.A. will likewise survive, it will just do so with a rising cost of living, some lifestyle changes, and some displacement.

How much is TBD. We really don't know the concrete answers at this stage.

But the challenges will be material.

Here's a further report on proposed changes to the East River Corridor for the same reasons, including burying the current East River Park.

NYC will remake the East River waterfront to fight climate change. It may not be enough

The city’s billion dollar plan to make the East River waterfront more resilient has a neighborhood up in arms.

ny.curbed.com

 

[Northern Light]

PS, on the subject of flooding/climate change; and how challenging protecting a place can be:

After a $14-Billion Upgrade, New Orleans' Levees Are Sinking

Sea-level rise and ground subsidence will render the flood barriers inadequate in just four years

www.scientificamerican.com

The US Army Corps of Engineers has only barely finished spending a whopping 14B US to rebuild and enhance New Orleans Levees.

But between the fact they are sinking; and the Ocean is already rising, they now feel the risk of substantial flooding may return, as soon as 2023!!!

 

[mdu]

That is just one of the possible problems with New Orleans. Also consider the possibility of a huge Mississippi flood hitting New Orleans from the other side, as well as the possibility of the Old River Control Structure getting overwhelmed and changing the Mississippi's flow (much more unlikely, but surely will happen within my lifetime) to the Atchafalaya.

 

[Johnny Au]

Here's a new video from Atlas Pro:

 

[Northern Light]

Here's a new video from Atlas Pro:

Good, if disturbing video.

 

[TrickyRicky]

Of local interest from the elevation maps would be the impact on the St. Lawrence Seaway. Perhaps of more immediate concern for Quebec downstream.

 

[Northern Light]

Of local interest from the elevation maps would be the impact on the St. Lawrence Seaway. Perhaps of more immediate concern for Quebec downstream.

The Great Lakes will not rise materially in sync w/Sea Level, at least not in the next few centuries.

Lake Ontario is the lowest elevation of the Great Lakes, it is over 240ft above Sea Level.

We may, however, encounter both more, and more intense rainfall in short periods; and it is plausible that Lake Levels could rise as much as 30cm as a result.

In that scenario, we would lose some of the parkland below the Bluffs, most of the Eastern Beaches, and a bit of the western Beaches.

The impact in Etobicoke would vary block by block, but would be unlikely to intrude onto shore in many places.

****

The rise of the St. Lawrence could be real trouble for Quebec City; less so for Montreal; but Charlemange just down stream could be in serious trouble.

Though, it needs to be said, that this is something will happen over several decades and many mitigatory actions can be taken.

***

In Canada, the large urban centre that would face the greatest Challenges are Vancouver; followed by Halifax.

 

[afransen]

I think the video is maybe a bit misleading. Estimates for sea level rise by 2100 are around 40 - 130cm. Most of the renderings shown in the video are more like 40m rise. That would require dramatic melting of Greenland and Antarctic ice sheets. Not going to happen in the foreseeable future (on human civilization time scales) barring some more extreme disaster than global warming on current trends.

 

[Memph]

Good, if disturbing video.

Their flooding maps don't match up to the elevation maps I have though. They say sea levels will rise 38cm and then show a map of the whole Delamarva peninsula being flooded, but on this map, even a 4m rise (10x what they say will happen by 2100), only about 20% of that peninsula will be under water.

Flood Map: Elevation Map, Sea Level Rise Map

Flood Map shows the map of the area which could get flooded if the water level rises to a particular elevation. Sea level rise map. Bathymetric map, ocean depth. Effect of Global Warming and Climate Change.

www.floodmap.net

Their map seems to be showing an amount of flooding that would only happen with 20-30m of sea level rise which is far far more than what's projected to be likely.

 

[TrickyRicky]

Humans will adapt no matter what the rate of sea rise; however, it’s worth mentioning that historically today’s atmospheric greenhouse gas concentrations are associated with a 50-60 foot rise in sea levels. That’s not by 2100 but that’s earth’s steady state baked-in even if we stop all human activity today.

 

[Memph]

I think the video is maybe a bit misleading. Estimates for sea level rise by 2100 are around 40 - 130cm. Most of the renderings shown in the video are more like 40m rise. That would require dramatic melting of Greenland and Antarctic ice sheets. Not going to happen in the foreseeable future (on human civilization time scales) barring some more extreme disaster than global warming on current trends.

Honestly, sea level rise isn't the biggest concern related to climate change in my opinion.

In a few special cases, it might be, like with Miami/South Florida, much of the city is less than a meter above sea level, so those areas would be at risk, and even if they can build barriers against that, there would also be the threat of seawater contaminating their water supply (which is ground water, ie at an even lower elevation, and mostly held in porous limestone that can seawater could theoretically go intrude into quite easily). Even Bangladesh is mostly 5-15m above sea level. With a 1.3m rise, some low lying regions like around Venice, Netherlands, Nile Delta, New Orleans and Miami would have to commit to infrastructure projects to protect from flooding, but a lot of coastal cities like Los Angeles, Sydney, Hong Kong, Mumbai, etc have enough elevation that they'd experience relatively little flooding.

My biggest concern is on changes in precipitation patterns causing desertification and loss of agricultural lands. And not just that, but also the fact that higher temperatures lead to more evaporation, so you would actually need more precipitation pretty much everywhere just to maintain soil moisture levels for the current crops. For example, much of the Canadian Prairies have similar amounts of precipitation to the Texas Panhandle, which is significantly more arid (because it's hotter = more evaporation).

My second biggest concern would be extreme weather - hurricanes and their storm surges, and tornadoes.

Then you also have issues like impact on Arctic ecosystems since warming at the poles is expected to be much more significant, and other vulnerable ecosystems (ex ocean acidification and coral reefs).

Maybe even sheer temperatures in the more tropical regions of the world where the heat is already hard to bear and many people can't afford air conditioning (or have to work outside)? I could see that being a bigger issue than sea levels.

 

[Memph]

Humans will adapt no matter what the rate of sea rise; however, it’s worth mentioning that historically today’s atmospheric greenhouse gas concentrations are associated with a 50-60 foot rise in sea levels. That’s not by 2100 but that’s earth’s steady state baked-in even if we stop all human activity today.

Is it though? Because greenhouse gases weren't the main driver of climate in much of the past, and the amount of carbon dioxide that can remain dissolved in the water of the oceans decreases with rising temperature. So other factors such as location of continents (polar continents facilitates formation of ice sheets and colder temperatures), Milankovic cycles, etc could have caused the prehistoric earth to be warmer, and as a result, caused the oceans to release carbon dioxide to the point where they reach today's concentrations.

That release in carbon dioxide could have amplified that warming further, but my point is that carbon dioxide alone wasn't necessarily the only reason why sea levels were 50-60 ft higher in those past periods.

 

[Deadpool X]

Although this thread is about comparison with Chicago but where does Toronto lie in comparison with New York? Is Toronto closing the gap (however big that may be) or is New York gaining lead in 150m+ buildings?