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Now Land Subsidence was once thought to be a mainly coastal phenomenon.

But as we just heard, it's showing up in most major cities across the U.S.

and many around the world.

Scientists say this so-called slow-moving hazard means Chicago's Urban Center is losing around 2 millimeters of elevation every year.

So just how serious is this problem and what can be done about it?

Joining us with more is many Trish's I associate professor in the Department of geosciences at Virginia Tech, coauthor of one of the study's referenced in our explainer.

Thank you very much for joining us.

We appreciate it.

You know, a lot of people might be surprised to hear that Chicago is extracting groundwater given that we live next to the world's largest fresh water source.

But why is groundwater extraction making Chicago vulnerable?

>> Thanks for having me.

So gun.

to expect But it happens causes poor spaces underground become So droplets holding land the ball.

extract him those into spaces cannot hold fate of 2 mentioned above them and begin to collapse as a result of those maps for system compacts, which many of us and in subsidence and surveys as the major defusing illusion of the satellite technology that devil, you know, that.

>> So we also heard and that video, Northwestern researchers.

>> Identified underground climate change is another issue.

How does that compound the problems that you identified with groundwater extraction?

>> Changing that 10 pitch and under the ground because somebody is particularly clay to default to become flow and also that the effects would add to the effect of COVID complexion.

And it's estimated that subsidence at the pace.

>> The kind of a 2 problems we're dealing with it once.

You know now in a May 2025 paper you and your CO authors found that Chicago was among a group of cities where about 98% of their area was affected by subsidence.

And Chicago is one of 5 cities where at least 10% of their area is sinking at at a higher rate at more than 3 millimeters per year.

What makes the city's, you know, including Chicago, especially vulnerable.

>> So what drives not subside?

It's a combination of the fact as you mentioned, you big deal at the beginning for that subsidence caused by politics section complexion of the caveat, but also nation.

I just I think it just the immediate impact of that.

Some sightings might be increased funding to Chicago and parts of the city that can get flooded during his reign.

But also storms don't get impacted them.

Subsidence has particularly if it's not even so economy different or that subsidence meaning a tough sinking at to put Jason to Chuck.

It is different.

So when you have such a different child movements, it would impact any kind of infrastructure that we have made it for structure, railways, pipelines, but also foundation of the building can I think that by that.

And if it's not make a difference, not stop over the course of 5 years can cause major damage infrastructure.

That's among to significant amount of dollars that needs to be a foot to to fix repair those and percent in for infrastructures.

there's some pretty striking graphics included in the paper, one of them that we have up here, you know, shows Chicago.

>> Next to Phoenix and Philadelphia, the better it is the more land is sinking, you know, but in this, this graphic shows that virtually all of metropolitan Chicago is sinking, whereas in other cities, the effects are more concentrated in certain areas.

Why is that?

>> So Chicago has been experiencing lot of carbon section.

But most of that has stopped over a few decades ago.

So as a result of massive ground out a section that the stock 18, 60 lasted 100 years.

>> compact even in snow expecting draw a lot to something caused busy compassion.

>> Which is the gradual complexion of our pool for that.

that continues over decades after and that's usually has gradual on and become innovative things affecting packed may generally feel Chicago.

Mitchell, more this at the same rate.

They don't come punditry to fit PGA a condition.

I just I think it just a minute to explain year to get there creates long Livingston formation of that subsidy and said the victim, a after she called the ad very soon.

great as he should study.

You know, 2 or 3 millimeters a year might not seem drastic.

But >> that can be an inch every 12 to 16 years.

We've got about mid 30 seconds left.

But what are some of the mitigation strategies?

Cities like Chicago can use?

>> So a lot very difficult to fathom mitigation strategy she used to use managed a recharge.

So that's solution in that we use Texas law to even be having week, something to do in given season.

We treat the Vulcan many money and be injected underground.

Feed the poor spaces and this may be saved a bucket for baby needed but also be recovered and compensates than that innovation and in cases even managed to a stop and subsidence.

All right.

Well, it might not be something everybody is thinking about, but certainly an important issue to draw their attention