- 72% of the earth is covered by ocean.

And we love living next to it, but honestly, the relationship has gotten a little complicated.

On average, sea level is currently rising about 1.4 inches per decade.

That rate is projected to increase as global temperatures warm.

And one of the most important tipping points is the leading edge of the Thwaites Glacier.

- Thwaites is called the doomsday glacier because if this glacier completely retreats, the world's oceans go up by 60 centimeters at least.

But if this system really does collapse we're more likely gonna look at a couple of meters of sea level rise and that's scary.

That's a lot of the Eastern seaboard.

That's a lot of Florida.

That that's a lot of Bangladesh underwater.

- [Maiya] Researchers estimate that the leading shelf could collapse in less than a decade.

That shelf slows the rest of the glacier from flowing into the ocean.

And Kiya was one of the first four people to ever stand on it.

- So we put a robot through the ice and it swam up to a grounding zone.

and we were just sitting there in the tent going, that's it, oh my gosh, we're seeing it.

Like, we are the first humans ever seeing this.

There is this huge kind of thermal reservoir of heat that's sitting beneath it.

- The threat posed by this kind of tipping point may already be eroding communities of color around the world.

We visited one that's being displaced, even though it isn't likely to be touched by rising water for an another century.

(light music) So we are in Miami to meet up with Scientist Tiffany Troxler to see sea level rise happen in real time.

- Today, we're gonna try to collect information that helps us to understand where, when, and how deep the flooding can be during these king tide events.

And understand the quality of the water when we have these tidal flooding events.

- King tide is a term used to describe an exceptionally high tide that occurs when the orbit of the earth, moon and sun line up just right.

They've always happened several times a year, but in the last 15 years, here in south Florida, tidal flooding has become four times more common.

Today, I'm joining Tiffany to help measure the extent of this year's highest tide.

- It's important to collect information about how tidal flooding is occurring in our urban environment so that we can better fine tune the adaptation strategies that we're considering now and in to the future.

- As we explored Miami during the highest tide of the year, flooding was easy to find.

And some residents are already choosing to leave very desirable waterfront property because it floods so frequently.

- Oh it's chilly!

- Is it cold?

- Yup.

- Okay, it's not that bad.

- All right, so water depth.

You're gonna take the water depth.

- Okay.

- It looks like you got eight and eight tenths.

- Cool here?

- Yeah, got it.

- All right.

- What you're observing today is a direct outcome of changing sea level over time.

We recognize it as an urgent issue that needs to be addressed right now with adaptation solutions and long term climate change mitigation.

- [Maiya] Projections show that by 2040, high tides will inundate city blocks.

And high tides in 2065 will put the Airbnb that we stayed in for this shoot underwater.

Along with most of Miami Beach.

It's a dire prediction, but most people who live in waterfront houses are likely to have the means to relocate.

And those homes still sell for top dollar.

So why at seven feet above sea level do residents of the Little Haiti neighborhood say they're being pushed out today?

When NOAA projects that the neighborhood is unlikely to be touched by rising sea levels for nearly a hundred years.

- Sea level rises affecting this neighborhood in particular because this is what they consider high ground.

What's happening at the beach, in terms of the beach, you know, being taken over by water as the water rises.

Now, this land is more valuable.

And it is it's forcing people out also too.

Because rents are going up, a lot of businesses, a lot of small mom and pop stores had to close because they couldn't afford the rents that was going up.

Yeah, it's basically gentrification.

It's forcing people out.

- [Maiya] In the last five years, real estate values in Miami have gone up 65%, but in Little Haiti, property values have gone up over 150%.

That's great if you own property, but 82% of the residents here rent their homes.

That's compared to 36% nationally.

- Paulette Richardson, who coined the phrase climate gentrification or climate change gentrification did it back in 2016.

And we all knew what was happening, but she put a name to it, you know?

We called it gentrification.

She said, no, this is climate gentrification.

The reason why we're really worried about climate change gentrification is the impact it's gonna have on that Haitian culture.

You know, this is an area of what you call Caribbean vibe, you know, where you know, families and you can walk down the street and people smile at you and say how you doing?

You know, whether you speak Creole or not, give you a smile.

It's that part of a culture that built this area.

For people to really experience what it means to have a community.

- Across Miami close to 85,000 residents live less than three feet above sea level.

Their homes are projected to be flooded by high tides as early as 2065.

And as we inch closer, equity issues are likely to become even more difficult to solve in Miami and beyond.

But how accurate are these projections?

- You know, there are something like 25 million people who live within the the zone that will be inundated by global sea level rise within the next several decades.

And the real question is how long does it take for that to happen?

Historically, our models have actually underestimated the rates at which that can happen.

And so I could give you a number.

I could say the models today say it might take half a century.

It might take a century.

But if you look at the history of the science, it's taught us, that if anything, many of these impacts are likely to proceed faster than our models have predicted.

If you looked at where we were say a decade ago, we weren't yet seeing major contributions from the collapsing of the ice sheets.

But now what we're seeing is that the ice sheets are starting to kick in.

That includes the Greenland ice sheet, and there may be enough ice there to contribute five meters of sea level rise.

A large part of the Antarctic ice sheet that could be part of a large scale collapse, you know over the next several decades to contribute maybe another five meters or so of sea level rise.

So together, we're talking on the order of 10 meters, you know, 30 feet of global sea level rise.

- [Maiya] 30 feet of sea level rise would be absolutely catastrophic.

And it's a long way off, but what matters right now is how Greenland and the Antarctic ice sheets respond in the near term, faster or slower than models predict.

To understand how feedback loops might work on the ice, back to Kiya Rivermen.

- In the world of studying glaciers, we used to think on a timeline of thousands of years.

We used to think that glaciers just kind of slowly respond to their climate.

And over time, that number has gotten shorter and shorter.

We've learned that, oh, actually glaciers respond on a couple years kind of timeframe to the changes that happen in the ocean and the atmosphere.

And then even more recently, we've seen that, oh wow.

In a matter of weeks, glaciers can significantly change.

- The clearest example of this occurred in 2002, when an unprecedented 3,250 square kilometers of the Larson B Ice Shelf collapsed in just over one month.

And this kind of melting is what we're seeing right now on Thwaites.

- Thwaites is a big thick glacier.

It flows out into the ocean and forms an ice shelf.

And that's the floating part of the glacier.

And that floating part runs into an island.

And you can imagine that acts kind of like a dam the ice shelf itself, when it falls apart, doesn't actually contribute to sea level rise because it's already floating in the ocean.

But as it breaks apart, it's no longer this stabilizing force for all of the ice behind it.

The dam is crumbling away.

And so this huge volume of ice on land behind it can speed up and flow into the ocean a lot more rapidly.

And so that's why we're focusing so much on this one little corner.

Because it's stabilizing this system right now.

- [Maiya] So the Thwaites expedition team drilled through the shelf to get an idea of what's happening underneath.

- One of the biggest surprises for us as part of putting our robot through the ice and measuring what the water column was like was learning just how warm and salty it is underneath this ice.

It's a couple degrees above its freezing point.

- And that wasn't the only surprise for the expedition.

- We put instruments on the surface of the ice.

And what we saw was the inland of the point where the glacier goes afloat, it bends and flexes with the tides in a way that sets up kind of like a pump that can bring seawater inland.

All the water that we're talking about is pretty cold, but to the ice, that's like putting blow torch underneath it.

Because that water is able to have so much melting impact just by being a couple of degrees above freezing.

You know, in the next 3, 4, 5, 6 years, we're going to see this ice shelf changing really rapidly and disintegrating.

- You know, dangerous climate change has arrived.

So the question is, how bad are we willing to let it get?

And there is a fairly widespread recognition that if we can keep the warming of the planet below about one and a half degrees Celsius, that's about three degrees Fahrenheit, there's still time to prevent the worst changes from happening.

And that requires a pretty dramatic reduction in carbon emissions.

So we can't just talk about these far off targets that sort of kick the can down the road several decades.

We've gotta talk about those near term targets that require action immediately.

There is a huge difference in what happens if we act dramatically now, or if we fail to act.

- Even though we think of this place as being far away and at the bottom of the world, we impact it and it impacts us.

And so it's not really that far away.

- As we've seen, sea level rise is happening.

And it's happening much faster than we previously believed.

Those most affected by sea level rise will be the poorest communities around the world.

That's a huge challenge.

And we'd like to know what you think about it.

Do you live in an area that's at risk of direct effects from sea level rise or one that's already being affected?

What would it take for you to decide to move?

Maybe the biggest question is this, can we come together to keep warming under the critical threshold of three degrees Fahrenheit?

Or are we destined for an even warmer world?