New Research Affirms Modern Sea-Level Rise Linked to Human Activities, Not to Changes in Earth’s Orbit

New Research Affirms Modern Sea-Level Rise Linked to Human Activities, Not to Changes in Earth’s Orbit

Extreme Sea Level Rise

Scientists boarding the D/V JOIDES Resolution off New Jersey in 1993. The sea level in an ice-free world would be 66 meters (216.5 feet) higher than now — shoulder-high to the Statue of Liberty. Credit: Kenneth G. Miller, James V. Browning, and Gregory S. Mountain.

Surprising glacial and nearly ice-free periods in last 66 million years.

New research by Rutgers scientists reaffirms that modern sea-level rise is linked to human activities and not to changes in Earth’s orbit.

Surprisingly, the Earth had nearly ice-free conditions with carbon dioxide levels not much higher than today and had glacial periods in times previously believed to be ice-free over the last 66 million years, according to a paper published in the journal Science Advances.

“Our team showed that the Earth’s history of glaciation was more complex than previously thought,” said lead author Kenneth G. Miller, a Distinguished Professor in the Department of Earth and Planetary Sciences in the School of Arts and Sciences at Rutgers University-New Brunswick. “Although carbon dioxide levels had an important influence on ice-free periods, minor variations in the Earth’s orbit were the dominant factor in terms of ice volume and sea-level changes — until modern times.”

Sea-level rise, which has accelerated in recent decades, threatens to permanently inundate densely populated coastal cities and communities, other low-lying lands and costly infrastructure by 2100. It also poses a grave threat to many ecosystems and economies.

The paper reconstructed the history of sea levels and glaciation since the age of the dinosaurs ended. Scientists compared estimates of the global average sea level, based on deep-sea geochemistry data, with continental margin records. Continental margins, which include the relatively shallow ocean waters over a continental shelf, can extend hundreds of miles from the coast.

The study showed that periods of nearly ice-free conditions, such as 17 million to 13 million years ago, occurred when the concentration of atmospheric carbon dioxide — a key greenhouse gas driving climate change — was not much higher than today. However, glacial periods occurred when the Earth was previously thought to be ice-free, such as from 48 million to 34 million years ago.

“We demonstrate that although atmospheric carbon dioxide had an important influence on ice-free periods on Earth, ice volume and sea-level changes prior to human influences were linked primarily to minor variations in the Earth’s orbit and distance from the sun,” Miller said.

The largest sea-level decline took place during the last glacial period about 20,000 years ago, when the water level dropped by about 400 feet. That was followed by a foot per decade rise in sea level — a rapid pace that slowed from 10,000 to 2,000 years ago. Sea-level rise was then at a standstill until around 1900, when rates began rising as human activities began influencing the climate.

Future work reconstructing the history of sea-level changes before 48 million years ago is needed to determine the times when the Earth was entirely ice-free, the role of atmospheric carbon dioxide in glaciation and the cause of the natural fall in atmospheric carbon dioxide before humans.


Reference: 15 May 2020, Science Advances.
DOI: 10.1126/sciadv.aaz1346

Rutgers coauthors include Professor James V. Browning, doctoral student W. John Schmelz and professors Robert E. Kopp, Gregory S. Mountain and James D. Wright, the senior author of the study.

Latest Estimates on Sea Level Rise by 2100 Are Worse Than We Thought

main article image

Oceans are likely to rise as much as 1.3 metres by 2100 if Earth’s surface warms another 3.5 degrees Celsius, scientists warned Friday.

By 2300, when ice sheets covering West Antarctica and Greenland will have shed trillions of tonnes in mass, sea levels could go up by more than five metres under that temperature scenario, redrawing the planet’s coastlines, they reported in a peer-reviewed survey of more than 100 leading experts.

About ten percent of the world’s population, or 770 million people, today live on land less than five metres above the high tide line.

Even if the Paris climate treaty goal of capping global warming below 2 °C is met – a very big “if” – the ocean watermark could go up two metres by 2300, according to a study in the journal Climate Atmospheric Science.

Earth’s average surface temperature has risen just over 1 °C since the pre-industrial era, a widely used benchmark for measuring global warming.

“It is clear now that previous sea-level rise estimates have been too low,” co-author Stefan Rahmstorf, head of Earth system analysis at the Potsdam Institute for Climate Impact Research (PIK), told AFP.

The new projections for both the 2100 and 2300 horizons are significantly higher than those from the UN Intergovernmental Panel on Climate Change (IPCC), including a special report on oceans it released in September.

“The IPCC tends to be very cautious and conservative, which is why it had to correct itself upwards already several times,” Rahmstorf said.

Ice sheets the main driver

Sea-level projections in the IPCC’s landmark 2014 Assessment Report were 60 percent above those in the previous edition, he noted. A new Assessment will be finalised by the end of next year.

While less visible than climate-enhanced hurricanes or persistent drought, sea level rise may ultimately prove the most devastating of global warming impacts.

Indeed, it is the extra centimetres of ocean water that make storm surges from ever-stronger tropical cyclones so much more deadly and destructive, experts say.

Benjamin Horton, acting chair of the Nanyang Technical University’s Asian School of the Environment in Singapore, led the survey to give “policymakers an overview of the state of the science”, a statement said.

Across the 20th century, sea level rise was caused mainly by melting glaciers and the expansion of ocean water as it warms.

But over the last two decades the main driver has become the melting and disintegrating of Earth’s two ice sheets.

Greenland and West Antarctica are shedding at least six times more ice today than during the 1990s. From 1992 through 2017 they lost some 6.4 trillion tonnes in mass.

Over the last decade, the sea level has gone up about four millimetres per year. Moving into the 22nd century, however, the waterline could rise ten times faster, even under an optimistic greenhouse gas emissions scenario, the IPCC has said.

The Greenland and West Antarctic ice sheets hold enough frozen water to lift oceans about 13 metres. East Antarctica, which is more stable, holds another 50 metres’ worth.

© Agence France-Presse


Were the predictions we made about climate change 20 years ago accurate? Here’s a look


When it comes to climate change, did we accurately predict in 2000 what would be happening now?

“What the models correctly told us 20 years ago is that if we continued to add fossil fuels at an increasing rate to the atmosphere, we’d see an increasing range of consequences, including a decline in Arctic sea ice, a rise in sea levels and shifts in precipitation patterns,” Weather Underground meteorologist Robert Henson told USA TODAY.

Overall, we’re running quite close to the projections made in 2000 for carbon dioxide concentration, global temperature and sea level, Henson said.

Here’s a look at climate change indicators for 2020:

Carbon dioxide

Carbon dioxide is the greenhouse gas that scientists say is most responsible for global warming.

Since the early 1990s, the carbon dioxide level in the Earth’s atmosphere has jumped from about 358 parts per million to nearly 412 ppm, according to the National Oceanic and Atmospheric Administration. That’s a 15% rise in 27 years.

More:10 years to save planet Earth: Here are 6 imaginative climate change solutions

Sea-level rise

Since 1992, the global sea level has risen on average 2.9 millimeters a year. That’s a total of 78.3 millimeters, according to NOAA.

Penn State University meteorologist Michael Mann argued that we underestimated the rate of ice sheet collapse, which has “implications for future sea-level rise.”

Both of the world’s giant ice sheets have lost tremendous amounts of ice in the past two to three decades: The Greenland ice sheet lost 5.2 trillion tons of ice from 1993 to 2018, according to a study in the Proceedings of the National Academy of Sciences.

The Antarctic ice sheet lost 3 trillion tons of ice from 1992 to 2017, according to a study in the journal Nature.

20 predictions for 2020:Here’s what people thought would happen by this year

Since 1993, there have been 212 weather disasters that cost the United States at least $1 billion each, when adjusted for inflation.

Weather disasters

Mann told USA TODAY that we “underestimated the dramatic increase in persistent weather extremes like the unprecedented heat waves, droughts, wildfires and floods we’ve witnessed in recent years.”

Since 1993, there have been 212 weather disasters that cost the United States at least $1 billion each, when adjusted for inflation.

In total, they cost $1.45 trillion and killed more than 10,000 people. That’s an average of 7.8 such disasters per year since 1993, compared with 3.2 per year from 1980 to 1992, according to NOAA.

“Just as climate models almost certainly underestimate the impact climate change has already had on such weather extremes, projections from these models also likely underestimate future increases in these types of events,” Mann wrote in The Washington Post last year.

“By and large, our models have gotten it right, plus or minus a little bit,” said Zeke Hausfather, a University of California-Berkeley scientist.

Report:Climate change is damaging the health of the world’s children and threatens lifelong impact

Global temps rising

Henson noted it’s clear that global climate models were on the right track 20 years ago: Global temperatures would continue to rise as greenhouse gases continued to accumulate in the atmosphere.

That’s been borne out: The global average temperature rose a tad more than a degree Fahrenheit since the mid-’90s, according to NOAA.

“The global temperature projections were just about on the money,” Mann said.

More on global warming:You just lived through the warmest decade on record – and it’s going to get hotter

These climate models weren’t designed to predict decade-by-decade variability, Henson said, so we didn’t fully anticipate the slowdown in global atmospheric warming in the first decade of this century and the much more rapid increase in the 2010s, both of which were linked to the evolving rate of heat storage in the ocean.

The annual average extent of Arctic sea ice has shrunk from 4.7 million square miles in 1992 to 3.9 million square miles in 2019, according to the National Snow and Ice Data Center. That’s a 17% decrease.

Droughts and wildfires

“Another thing beyond the scope of year-2000 outlooks were some aspects of regional climate change,” Henson said. “For example, it’s now clear that droughts in California are much more likely to be ‘hot’ droughts, and this has laid the groundwork for longer, more devastating wildfire seasons.”

The number of acres burned by wildfires in the USA has more than doubled from a five-year average of 3.3 million acres in the 1990s to 7.6 million acres in 2018, the National Interagency Fire Center said.

‘Sunny day’ flooding

 “We’re also appreciating the threat posed by ‘sunny day’ flooding much more than we did in 2000,” Henson said. “Tidal flooding is far more frequent on many parts of the Gulf and Atlantic coast than it was 20 years ago, and NOAA has projected that some locations could see more than 80 flood days a year as soon as the 2040s.”

Contributing: The Associated Press

Research points to unprecedented and worrying rise in sea levels

deep sea
Credit: CC0 Public Domain

A new study led by Simon Fraser University’s Dean of Science, Prof. Paul Kench, has discovered new evidence of sea-level variability in the central Indian Ocean.

Prof. Kench says, “We know that certain types of fossil corals act as important recorders of past sea levels. By measuring the ages and the depths of these fossil corals, we are identifying that there have been periods several hundred years ago that the sea level has been much lower than we thought in parts of the Indian Ocean.”

He says understanding where sea levels have been historically, and what happens as they rise, will provide greater insights into how coral reefs systems and islands may be able to respond to the changes in sea levels in the future.

Underscoring the serious threat posed to  and communities in the region, the , which began in 2017, further suggests that if such acceleration continues over the next century, sea levels in the Indian Ocean will have risen to their highest level ever in recorded history.

The  authored by Kench and others, and titled “Climate-forced  lowstands in the Indian Ocean during the last two millennia” was published this week in the scientific journal Nature Geoscience.

London has spent billions, but no one can escape climate change

Updated 9:12 AM ET, Mon December 16, 2019

London (CNN)The stark reality of climate change is that even the cities that seem best defended against rising sea levels face the potential of catastrophic flooding.

Take London, capital of the UK.
It’s in a strong position: Wealthy, with a government that recognizes the danger of climate change, and a river that can — for now — be shut off from dangerous tidal and storm surges.
And yet, no city or person is immune from climate change.
At least 1 million Londoners live in the estuary’s natural floodplain and 16% of the city’s properties — 84,000 — are considered to be at “significant or moderate risk.”
Humans have already put so much greenhouse gas into the earth’s atmosphere that some amount of sea level rise is inevitable.
“Even if we reduce our emissions to negative now, we will see at least a meter of sea level rise,” the oceanographer Ivan Haigh told CNN.
Clearly, quitting all emissions immediately is off the table.
So how soon will we have a meter of sea level rise? And how much higher will it go?

‘The highest I’ve seen’

That’s a question that Haigh, associate professor at the UK’s University of Southampton, has devoted much of his career to studying.
CNN caught up with him in November on a rainy day along the Thames, a short walk from the Houses of Parliament. High tide was approaching.
“I have to admit, I come up to London quite a lot, and this is one of the highest I’ve seen it (the river),” Haigh said.
It’s easy to go through your day in this city and not notice the river. But it just took crossing a short sea wall that runs along the promenade for the water to rush over our feet.
Londoners have long been aware of the threat from the water that brought them so much wealth as the city grew around the Thames.
After years of deliberation, a giant flood defense system was built across the river, completed in 1982.
Spanning 520 meters (1,706ft) across the Thames, the barrier uses 10 enormous steel gates to shut the city off from tidal surge. Each gate, which rotates into position, stands more than five stories high.
Rising sea levels put London at risk of flooding

Play Video

Rising sea levels put London at risk of flooding 02:49
It can be used to protect against both tidal flooding and that from raining, “fluvial,” which bloats the river.
The UK Environment Agency, which operates the barrier, says that as climate change necessitates more closures, its use “will need to be conserved for tidal flood risk management — the purpose for which it was designed.”
With only 30 years of barrier usage, anomalous years drown out clear trends. In 2013-14, it was closed 50 times, mostly for river flooding — far more than any other year before or since.
“Sea level rise is a relatively slow process,” Haigh said. “But it’s starting to accelerate. So although we don’t see a trend now, with sea levels accelerating after 2050, or even before, that trend should become apparent.”
The oceanographer Ivan Haigh speaks to CNN along the River Thames.

The last week of November in which we met Haigh saw an unusually high tide.
Those who run the barrier said it was a close call whether to close it that day. The tide got to about 40 centimeters (16 inches) away from the trigger point — a complex calculation depending on the type and location of high water.
The barrier, Haigh said, gives an “artificial” sense of protection.
“A lot of people living in the flood plains don’t realize they’re living in the flood plains.”

Crunching the numbers

Jonathan Bamber, professor of physical geography at the University of Bristol, crunched the numbers.
Using his own research, Bamber provided CNN with projections for sea level rise in the Thames Estuary every decade until 2300.
If we keep increasing emissions into the future — the “business as usual” scenario — temperatures are almost certain to rise more than two degrees over pre-industrial level.
That is the maximum target set out by the Paris Climate Accords, to avoid the most catastrophic impacts of climate change.
That means we will likely see a meter of sea level rise by 2100, from a combination of warmer water, which expands, and melting ice sheets in Greenland and Antarctica.
The Thames Barrier is only expected to last until 2070.
“The crunch point actually is not so much the height of sea level rise, it’s how many times you have to close the barrier,” Haigh said. “If we get to a point where we’re closing too much, then the costs don’t stack up and we will need a new system.”
The math is simple: The more the Thames Barrier is used, the faster it will age, and the greater the need for a replacement.
The UK Environment Agency has developed a detailed plan to deal with the reality that London’s collective flood defenses “will require replacement or major repair at a cost of several billion pounds.”
Already, the agency anticipates spending £300 million ($395 million) between 2010 and 2034 on protecting London’s floodplain.
Among the front-runners for the long term, when the Thames Barrier is no longer usable, is the construction of an entirely new barrier, much further downstream towards the sea, near the town of Dartford in Kent.
But that one meter of sea rise is a best-case scenario.
Bamber’s numbers predict that by 2300, the sea level in the Thames Estuary is likely to reach more than three meters — and could go even higher, if emissions and temperatures continue to rise unabated.
“We have several billion pounds of coastal defense infrastructure,” Haigh said. “Other places in the world are not going to be as prepared.”
Just how bad will it be?
“That’s very much dependent on whether we follow the Paris Agreement or not,” he added.

Venice floods: Climate change behind highest tide in 50 years, says mayor

Media captionParts of Venice have been left under water by record flooding

Severe flooding in Venice that has left much of the Italian city under water is a direct result of climate change, the mayor says.

The highest water levels in the region in more than 50 years would leave “a permanent mark”, Venice Mayor Luigi Brugnaro tweeted.

“Now the government must listen,” he added. “These are the effects of climate change… the costs will be high.”

A man crosses the flooded St. Mark's Square in high water levels in Venice, 13 November 2019Image copyrightGETTY IMAGES

The waters in Venice peaked at 1.87m (6ft), according to the tide monitoring centre. Only once since official records began in 1923 has the tide been higher, reaching 1.94m in 1966.

Images showed popular sites left completely flooded and people wading through the streets as Venice was hit by a storm.

A man stands in water at the flooded St Mark's Square during exceptionally high water levels in Venice, Italy, 13 November 2019Image copyrightREUTERS

St Mark’s Square – one of the lowest parts of the city – was one of the worst hit areas.

A woman walks past flooded furniture of a cafe terrace as Venice suffers in extremely high water levels, 13 November 2019Image copyrightGETTY IMAGES

St Mark’s Basilica was flooded for the sixth time in 1,200 years, according to church records. Pierpaolo Campostrini, a member of St Mark’s council, said four of those floods had now occurred within the past 20 years.

The flooded crypt of St Mark's Basilica is pictured during exceptionally high water levels in Venice, Italy, 13 November 2019Image copyrightREUTERS

The mayor said the famous landmark had suffered “grave damage”. The crypt was completely flooded and there are fears of structural damage to the basilica’s columns.

People walk the streets of Venice during exceptionally high water levels, 13 November 2019Image copyrightREUTERS

The city of Venice is made up of more than 100 islands inside a lagoon off the north-east coast of Italy.

Two people died on the island of Pellestrina, a thin strip of land that separates the lagoon from the Adriatic Sea. A man was electrocuted as he tried to start a pump in his home, and a second person was found dead elsewhere.

People wade through floodwatersImage copyrightEPA

Mr Brugnaro said the damage was “huge” and that he would declare a state of disaster, warning that a project to help prevent the Venetian lagoon suffering devastating floods “must be finished soon”.

“The situation is dramatic. We ask the government to help us,” he said on Twitter, adding that schools would remain closed until the water level subsides.

People walk on a catwalk connecting to St Mark's SquareImage copyrightREUTERS

He also urged local businesses to share photos and video footage of the devastation, which he said would be useful when requesting financial help from the government.

People throughout the city waded through the flood waters.

A taxi boat is stranded on the streets of VeniceImage copyrightAFP

A number of businesses were affected. Chairs and tables were seen floating outside cafes and restaurants.

In shops, workers tried to move their stock away from the water to prevent any further damage.

Venice floods

One shopkeeper, who was not named, told Italy’s public broadcaster Rai: “The city is on its knees.”

A flooded shop in VeniceImage copyrightREUTERS

Three waterbuses sank, but tourists continued their sightseeing as best they could.

One French couple told AFP news agency that they had “effectively swum” after some of the wooden platforms placed around the city in areas prone to flooding overturned.

People wade through water in St Mark's SquareImage copyrightAFP

On Wednesday morning, a number of boats were seen stranded.

A project to protect the city from flooding has been under way since 2003 but has been hit by soaring costs, scandals and delays.

St Mark's Basilica and a section of the Doge's Palace are left floodedImage copyrightAFP

The so-called Mose project – a series of large barriers or floodgates that would be raised from the seabed to shut off the lagoon in the event of rising sea levels and winter storms – was successfully tested for the first time in 2013.

The project has already cost billions of euros in investment. According to Italy’s infrastructure ministry, the flood barriers will be handed over to the Venice city council at the end of 2021 following the “final phase” of testing.

Italy was hit by heavy rainfall on Tuesday with further bad weather forecast in the coming days. Venice suffers flooding on a yearly basis.

Is climate change behind Venice flooding?

By BBC meteorologist Nikki Berry

The recent flooding in Venice was caused by a combination of high spring tides and a meteorological storm surge driven by strong sirocco winds blowing north-eastwards across the Adriatic Sea. When these two events coincide, we get what is known as Acqua Alta (high water).

This latest Acqua Alta occurrence in Venice is the second highest tide in recorded history. However, if we look at the top 10 tides, five have occurred in the past 20 years and the most recent was only last year.

While we should try to avoid attributing a single event to climate change, the increased frequency of these exceptional tides is obviously a big concern. In our changing climate, sea levels are rising and a city such as Venice, which is also sinking, is particularly susceptible to such changes.

The weather patterns that have caused the Adriatic storm surge have been driven by a strong meridional (waving) jet stream across the northern hemisphere and this has fed a conveyor belt of low pressure systems into the central Mediterranean.

One of the possible effects of a changing climate is that the jet stream will be more frequently meridional and blocked weather patterns such as these will also become more frequent. If this happens, there is a greater likelihood that these events will combine with astronomical spring tides and hence increase the chance of flooding in Venice.

Furthermore, the meridional jet stream can be linked back to stronger typhoons in the north-west Pacific resulting in more frequent cold outbreaks in North America and an unsettled Mediterranean is another one of the downstream effects.

All images subject to copyright.

Luxurious living has made us a self-endangering species

PNAS first published November 7, 2019.
Tony E. Wong

The emission of greenhouse gases into Earth’s atmosphere is a by-product of modern marvels such as the production of vast amounts of energy, heating and cooling inhospitable environments to be amenable to human existence, and traveling great distances faster than our saddle-sore ancestors ever dreamed possible. However, these luxuries come at a price: climate changes in the form of severe droughts, extreme precipitation and temperatures, increased frequency of flooding in coastal cities, global warming, and sea-level rise (1, 2). Rising seas pose a severe risk to coastal areas across the globe, with billions of US dollars in assets at risk and about 10% of the world’s population living within 10 m of sea level (3⇓–5). The price of our emissions is not felt immediately throughout the entire climate system, however, because processes such as ice sheet melt and the expansion of warming ocean water act over the course of centuries. Thus, even if all greenhouse gas emissions immediately ceased, our past emissions have already “locked in” some amount of continued global warming and sea-level rise. In PNAS, Nauels et al. (6) <<>>examine how greenhouse gas emissions since 1750, and anticipated future emissions, contribute to global sea-level rise.

They find that emissions from 1750 to 1991 have committed us to about 60 cm of additional sea-level rise by the year 2300, relative to the mean from 1986 to 2005, with another 24 cm stemming from greenhouse gases emitted between 1991 and 2016. So, through our emissions thus far in modern human history, we have committed to a total sea-level rise of about 84 cm over the next couple of centuries. This is the price we pay for the luxury of about 200 y of relatively unchecked greenhouse gas emissions.

Aug 6, 2018  Even if the Paris agreement is successfully implemented, the planet could still heat up by 5 degrees Celsius, scientists warn.
The lead authors say:
“Our study suggests that human-induced global warming of 2 degrees Celsius may trigger other Earth system processes, often called ‘feedbacks,’ that can drive further warming — even if we stop emitting greenhouse gases.”
“These tipping elements can potentially act like a row of dominos. Once one is pushed over, it pushes Earth toward another. It may be very difficult or impossible to stop the whole row of dominoes from tumbling over.”

Scientist still sees hope in climate fight

Climatologist Phil Mote

Phil Mote, the director of the Oregon Climate Change Research Institute at Oregon State University, discusses climate change and its myths at the Columbia Forum on Tuesday night.

Climatologist Phil Mote presented 10 myths about climate change Tuesday night but ended his presentation with an 11th myth: There is no hope.

“I find several reasons for hope,” the director of the Oregon Climate Change Research Institute at Oregon State University told the Columbia Forum.

Mote pointed to an increase in solar panel installation, more people driving electric cars, wave energy testing off the coast of Newport, geothermal power plants and teenage activist Greta Thunberg.

“The young people getting passionate about this and pushing for change gives me great hope,” he said.

Mote’s presentation at Baked Alaska in Astoria opened the 30th season of the Columbia Forum speaker series.

He addressed some of the most common myths about climate change, including that the Northwest will see little effect from global warming.

“We’re seeing all these fires and they are clearly linked empirically to the warming climate,” Mote said. “It’s not like fires have never existed, but they are bigger.”

He said rising temperatures cause snow drought, which in the distant future will affect flow levels in the Columbia River to run counter to irrigation demands.

“Rising seas and increasing storminess are already wreaking havoc with many of the coastal areas,” Mote said.

He shared an analysis of infrastructure at risk from 4 feet of sea level rise in counties along the coast.

Clatsop County was ranked the most affected county in all categories, including the number of people affected, number of homes, number of miles of roadway and number of sewage treatment plants.

“So, even 4 feet of sea level rise or high water event can really have impacts,” Mote said.

Another myth he shared is the idea global warming is natural.

“There’s a big difference between the human influence and the natural influences and together they can explain most of what we saw in the 20th century record,” Mote said.

However, he said science shows that human influence has been the dominant cause of global warming.

And scientists are not divided over that, he said.

“The closer you are to the evidence and to the work that all of the scientific community is doing, the clearer it is that humans are responsible,” Mote said.

He also addressed the common misconception that there is time to prevent irreversible damage from climate change.

“At whatever point we stabilize CO2 concentrations in the atmosphere, in other words at whatever point we’re done emitting CO2, that’s roughly where the temperature will stop,” Mote said. “There’s nothing particularly magical about 2 degrees Celsius.”

He said there’s more impact with each degree, but there is no tipping point. He said carbon dioxide emissions just need to be reduced as quickly as possible.

“There’s a huge gap from where we’re headed absent of policy and where we think we want to go in order to stabilize global climate. And this is one of the most out-in-front states in the union, California and a couple of others being ahead of us,” Mote said.

He said stabilizing carbon dioxide emissions will be a major challenge.

“My view as a scientist is I want to see emissions reduced because I understand the harm that will happen if we don’t reduce emissions. And whatever policy gets us to reduce emissions is fine with me — if it’s cap and trade, if it’s carbon tax, if it’s just executive branch regulation — at any means necessary,” he said.

What climate change will do to three major American cities by 2100

Climate change is already here. It’s not something that can simply be ignored by cable news or dismissed by sitting US senators in a Twitter joke. Nor is it a fantastical scenario like The Day After Tomorrow or 2012 that starts with a single crack in the Arctic ice shelf or earthquake tearing through Los Angeles, and results, a few weeks or years later, in the end of life on Earth as we know it.

Instead, we are seeing its creeping effects now—with hurricanes like Maria and Harvey that caused hundreds of deaths and billions of dollars in economic damage; with the Mississippi River and its tributaries overflowing their banks this spring, leaving huge swaths of the Midwestern plains under water. Climate change is, at this very moment, taking a real toll on wildlife, ecosystems, economies, and human beings, particularly in the global south, which experts expect will be hit first and hardest. We know from the increasingly apocalyptic warnings being issued by the United Nations that it will only get worse.

But these early omens of our unstable, hot, wet future can be difficult to wrap our heads around. So Teen Vogue partnered with the team at the nonprofit news service Nexus Media, who developed a timeline predicting how climate change could affect three major US cities over the course of the 21st century. Climate change will look different in different places across the world, but we chose three places with distinct geographic concerns and climate vulnerabilities—to ground all the ominous statistics and headlines in a real sense of place. These are cities you may have visited, or where you may have family, or where you may even live.

According to the research Nexus compiled, St. Louis will see flooding, extreme heat, severe rainfall, and drought in the surrounding farmland. In Houston, on the Gulf of Mexico, hurricanes will grow more destructive and temperatures will soar. San Francisco will witness rising sea levels, fierce wildfires, and extreme drought.

This timeline is based on interviews with a dozen climate experts and a review of several dozen scientific studies. The projections assume an average sea level rise of six feet by 2100—a little more in some places, and less in others—and the business-as-usual emissions scenario, which assumes that we will continue to pollute and use fossil fuels at our current rate.

Rather than a scientific assessment, it is a rigorously researched prediction of what our future could bring unless we come together as a country and as a global community—fast—to address climate change as the crisis it is.

As Katharine Hayhoe, a climate scientist at Texas Tech University, put it: “The future is not set in stone. Some amount of change is inevitable. It’s as if we’ve been smoking a pack of cigarettes a day for decades, but we don’t have lung cancer yet.”

“The amount of change that we’re going to see—whether it’s serious, whether it’s dangerous, whether it’s devastating, whether it’s civilization-threatening—the amount of change we’re going to see is up to us,” she continued. “It depends on our choices today and in the next few years.”

The aftermath of Hurricane Harvey in Houston, Texas
The aftermath of Hurricane Harvey in Houston, Texas.



Houston’s starting to get hot. It’s now about one degree fahrenheit warmer in Houston than it was in the second half of the 20th century. Houstonians can expect especially balmy falls this decade, as autumns are warming faster than other seasons in Texas.

Houston knows how much it stands to lose from climate change. In 2017, Hurricane Harvey devastated the city, which was supercharged by warm waters in the Gulf. But Houston is also helping to drive the rise in temperature. Several major oil companies and a vast network of oil refineries and petrochemical plants call the city home.

St. Louis

This decade, St. Louis is expected to be more than two degrees fahrenheit warmer than it was, on average, during the latter half of the 20th century. While locals have endured more sweltering summer days, they have felt the change the most during the cold months. Missouri winters are warming faster than summers, springs, and falls.

Warmer air holds more water, which can lead to more severe rainfall. In recent years, rainstorms have pummeled the Midwest and led to widespread flooding across the region. In 2019 in St. Louis, rivers reached near-historic levels, and floodwaters inundated the area around the city’s iconic Gateway Arch.

This storm wasn’t a blip on the radar, but rather a sign of what’s to come. As the planet heats up, St. Louis can expect more extreme rainstorms—and more orders to evacuate low-lying neighborhoods.

San Francisco

For San Franciscans, the beginning of the decade will feel only a little different from past years. In 2020, it’s expected to be less than one degree fahrenheit warmer in San Francisco than it was, on average, between 1950 and 2000. The change is small, but locals can sometimes feel it in the spring, which is warming faster than the other seasons, or on especially hot days.

But there are new worries for the city. Rising temperatures have fueled ongoing drought in recent years, which has, in turn, led to more wildfires. Fires now burn more regularly across the Sierra Nevada as well as coastal mountain ranges. The flames may ruin plans for weekend getaways to Yosemite or deliver noxious smoke to the Bay Area. And locals may start to reach for air masks as dangerously smoky days become more common.

“We get a lot of the smoke that comes from the wildfires that happen in inland California, and that makes it really hard to breathe the air,” said Kristy Dahl, a climate scientist at the Union of Concerned Scientists, who is based in San Francisco. “Last year when there was a massive wildfire hundreds of miles away, San Francisco for a day [ranked among] the worst air quality in the entire world.”



By 2030, temperatures are expected to have warmed almost two degrees fahrenheit in Houston. Seas are expected to have risen a little more than a foot, enough to occasionally flood some low-lying areas outside the city. Warmer waters in the Gulf of Mexico will raise the speed limit for winds during hurricanes and ramp up rainfall during storms.

“Hurricanes are not getting more frequent, but they are getting stronger and bigger and slower,” said Katharine Hayhoe, a climate scientist at Texas Tech University. “They’re intensifying faster and they have a lot more rain associated with them today than they would have had a hundred years ago.”

St. Louis

By 2030, temperatures are expected to have warmed around three degrees fahrenheit in St. Louis. The kind of rainstorm that currently strikes the Midwest around once every five years will hit around once every three years this decade.

“We’ve seen these record-breaking, devastating floods in the Midwest,” said Katharine Hayhoe, a climate scientist at Texas Tech University. “It’s not like they’ve never had floods before, but the floods are just getting a lot worse and a lot more frequent.”

This could mean trouble for local infrastructure. Rivers swell after heavy rains, and the rush of water can weaken bridges by carrying away sediment from around their foundations. This could be a big problem in Missouri, which is home to hundreds of aging bridges, many of which have been deemed deficient. Climate change could mean even more heavy repair costs for taxpayers.

San Francisco

This decade, the rise in temperature is expected to pass two degrees fahrenheit in San Francisco. That may not feel like a lot in the city. But warmer weather is taking a serious toll.

California’s drought will get progressively worse this decade, the product of warmer temperatures drying out soil and meager rainfall failing to replace the water lost. Rising temperatures will also yield less snowfall. The snow that does come down will melt in the spring and early summer, depriving the state of a critical source of water in the late summer, when, historically, melting snow has fed streams and rivers.

The snow drought will strain farmers in the Central Valley, while putting pressure on cities to use less water. The water restrictions the state put in place in 2018 will have grown much more severe in the past 12 years. Officials could urge Californians across the state to take shorter showers and stop watering their lawns to cope with the worsening drought.

A visualization of how heat hurts the economy



This decade, sea level rise around Houston is projected to reach two feet, enough to inundate much of nearby Freeport and Jamaica Beach. That extra water will mean that hurricanes, when they strike, will deliver more powerful floods to coastal areas.

“A small and steady rise of the water level elevates a platform for flooding that we’ve had throughout history,” said Maya Buchanan, a sea level rise scientist at Climate Central. “That means larger storm surges.”

That’s bad news for people who live near the shore. Around half of deaths caused by hurricanes are the result of coastal flooding, and waters tend to inundate poor neighborhoods and neighborhoods of color, which are more likely to lie in flood-prone areas.

St. Louis

In 2040, St. Louis is expected to be four degrees fahrenheit warmer than it was at the end of the last century. While that may sound like a small number, it means big problems for the city. A small uptick in the average temperature could lead to milder winters, stifling summers, and changing rainfall.

St. Louis will tend to see wetter springs and drier summers. That means the region will withstand heavier downpours, but it will also endure long stretches without a drop of rain. Despite the growing peril of major flooding, extended dry spells and rising temperatures will dry out the land. Drought will set in in Missouri, endangering farms.
And just remember—it will never be this cool again.

San Francisco

By 2040, sea levels are predicted to rise around one foot, enough to encroach the beaches on the west side of the city and Candlestick Point on the east, popular recreation areas. Parts of San Francisco Airport and Oakland Airport will flood regularly, making air travel in and out of the city more difficult.

Drought will have grown increasingly severe. Forests will dry out, and become vulnerable to bark beetles, which burrow into trees to lay their eggs. Healthy trees can ward off the bugs by covering them in resin—but already struggling trees have no way to protect themselves.

Large parts of forests will die, and the dead trees will become tinder for wildfire. In 2040, fires are expected to burn around twice as much of the Sierra Nevada as they do today. Areas south of San Francisco will also grow more vulnerable to erupting in flames.



By midcentury, temperatures are expected to have warmed more than three degrees fahrenheit in Houston. Waters in the Gulf of Mexico will have also warmed, fueling more dangerous storms.

In the decades to come, the Gulf will see more category-four and -five hurricanes, like Hurricane Harvey and Hurricane Katrina, according to Suzana Camargo, a climate scientist at Columbia University. Warm water is like ammunition for cyclones, arming them with more powerful winds and heavier rains. People might want to think twice before they purchase a home in Houston.

“I think people have to think very carefully how they are going to plan when they want to buy a house,” Camargo said, explaining that in the future, cyclones will deliver more flooding to seaside cities and towns.

St. Louis

St. Louis is expected to have heated up by more than five degrees fahrenheit on average by the middle of the century. Hot weather will dry out soil. Past 2050, the Central Plains, including much of Missouri, can look forward to decades-long drought.

This drought will be especially disastrous for Missouri farmers. Growers will have to take more water out of underground aquifers to feed their crops, drawing down a limited supply of groundwater, often at great cost. This, in turn, could drive up the price of food.

San Francisco

By 2050, temperatures in San Francisco are expected to have risen more than three degrees fahrenheit. In the second half of this century, changing weather patterns will yield lasting dry spells, leaving much of California to endure long stretches without rain. Around the time someone graduating high school today turns 50, they can expect California to enter a decades-long drought—with disastrous consequences.

Farmers in California will have to draw more and more water from underground. Eventually, they may not be able to grow fruits and vegetables in parts of the state. This will drive up the cost of many foods, such as strawberries, almonds, and lemons.

Snow will also start to disappear from the Sierra Nevada. By 2050, projections say, there will be a third less snow than we see today. San Francisco depends on that snow for its water, and a dry Sierra Nevada could mean a looming water crisis for the city.

The drought will also leave California’s forests all the more vulnerable to wildfire—fires that could cover San Francisco in smoke, making it dangerous to go outside.

A visualization showing where people will remove to escape rising sea levels



By 2060, temperatures are expected to have warmed by more than four degrees fahrenheit. The city could see up to 25 days a year with temperatures over 100 degrees fahrenheit.

Local sea level rise, meanwhile, is expected reach three feet during this decade. This will raise the level of Buffalo Bayou, the waterway that stretches through the middle of Houston. The Scholes International Airport in nearby Galveston will sink into the sea, and at high tide, water will flood much of the San Jacinto Battleground, site of the 1836 clash where Sam Houston, the city’s namesake, overcame the Mexican Army.

St. Louis

St. Louis is expected hit a six-degrees-fahrenheit increase in its average temperature this decade. While this might be bad news for humans, it’s good for many insects, who love warm weather. Rising temperatures will bring disease-carrying mosquitoes to St. Louis’s doorstep. Missourians will have to be more vigilant about their health as the bugs could spread tropical viruses like Zika, dengue, and yellow fever around the warming Midwest.

Climate change will also bring more deer ticks to St. Louis. Because warmer air can hold more water, as temperatures rise, so does humidity—and deer ticks thrive in humid weather. While ticks are little seen in Missouri today, later this century they will fan out across the state, potentially spreading Lyme disease. Those afflicted will endure fever, headache, and fatigue. They may see their joints swell or feel their face droop.

San Francisco

By 2060, temperatures in San Francisco are expected to have risen by more than four degrees fahrenheit.

Wildfires will burn roughly three times as much of broad swaths of the Sierra Nevada as they do today, laying waste to large stretches of California’s pristine forests.

This decade, sea level rise is projected hit two feet. Water will begin to spill over the edges of the Mission Creek Channel, while threatening routine floods around San Francisco’s iconic Fisherman’s Wharf. Waters will have flooded much of nearby San Rafael, north of San Francisco. To the south, Foster City will be underwater, displacing thousands of residents—many of whom currently work in the tech industry.



By 2070, Houston is projected to be more than five degrees fahrenheit hotter than at the end of the 20th century. This warming is part of a larger trend that is heating up the planet and melting ice in Greenland and Antarctica, raising the sea level near the city.

“As flooding events get more severe, that can impact property values, and that could impact where people decide to live,” Buchanan said, explaining that rising seas will drive down the value of homes in low-lying areas.

By this time, waters will have already subsumed much of the coastline from Freeport, south of Houston, all the way to New Orleans. Rising seas will make much of the Gulf coast unrecognizable as the ocean swallows up most of southern Louisiana. Later this decade, sea levels are expected to have risen by four feet.

St. Louis

In 2070, St. Louis is projected to be more than seven degrees fahrenheit hotter than it was at the end of the last century. Before the decade is through, the city is expected to see eight degrees fahrenheit of warming. Rising temperatures will have utterly transformed the weather in Missouri, making it virtually unrecognizable to current residents. The city will see around 20 fewer days of frost each year than it does today, as well as around 20 extra days with temperatures over 95 degrees fahrenheit. The heat will be felt most acutely in neighborhoods short on trees and parks.

Outside the city, severe heat will cripple the growth of corn and soybeans at nearby farms. So will drought, which experts say will be worse than at any time in living memory. The state will endure more consecutive days without rain. When it does rain, however, it will pour. Warmer temperatures will produce more extreme rainfall.

San Francisco

By 2070, San Francisco’s average temperature is expected to have warmed by more than five degrees fahrenheit. Drought will be more severe than at any time in living memory. Rising temperatures and diminished rainfall will take a toll on trees around the San Francisco Bay. More and more evergreen forests will die off and grasslands will spring up in their place, fundamentally changing the landscape around the city.

A visualization of how cities will feel in 2080



By 2080, temperatures are projected to have warmed around six degrees fahrenheit on average, a dizzying change in the weather that means Houston won’t feel like Houston anymore.

The city will grow warmer and wetter. Around 2080, Houston will feel something like Ciudad Mante in Mexico does today, with its warmer, drier winter.

As the climate changes, Houston’s native wildlife could start to head north. At the same time, plants and animals that currently make their home south of Houston may start to work their way toward the city.

St. Louis

St. Louis is expected to be nearly nine degrees fahrenheit warmer by 2080. The temperature will have changed so drastically that St. Louis no longer feels like the same city.

Around 2080, St. Louis will start to feel like Prosper, Texas, does today. This new St. Louis will be hotter and drier. Summer weather will go from balmy to sweltering, and the city will see much less rain during the warm months.

It’s not just that St. Louis will feel more like Prosper. It might start to look like it too. Animals that currently live around Prosper could head northward as the climate changes, searching for a new home that feels like their old one. At the same time, the shrubs and grasslands that stretch across north Texas could start to edge their way toward Missouri.

San Francisco

By 2080, the average temperature is expected to have risen by more than six degrees fahrenheit in San Francisco. The city will start to feel a lot like present-day Los Angeles. The weather will be warmer and drier, much like the current climate in Palos Verdes Estates, a coastal city in the Los Angeles area.

With less rainfall, many of the trees that make their home in San Francisco will die. At the same time, the smaller, scrubbier plants that make their home in LA could migrate toward the city. It’s not just that San Francisco will start to feel like LA, scientists say. It might start to look like it too.



By now, temperatures are projected to have warmed close to seven degrees fahrenheit, while sea levels will have risen five feet, subsuming the coastline. Much of nearby Galveston is underwater.

It’s not just hot days that threaten Houston. Rising temperatures will allow the air to hold more water, increasing humidity—which could be a big problem for public health.

“As humidity rises, it becomes harder and harder for the sweat to evaporate off our skin—and it’s that evaporation of sweat that cools our bodies,” said Kristy Dahl, a climate scientist at the Union of Concerned Scientists. “So it might only be a temperature reading of 90 degrees, but if you have 60% humidity, it’s going to feel hotter than 90 degrees.”

Dahl said that Houston will heat up so much that it will be hard to quantify how hot it will feel.

“By the end of the century, Houston would see about three weeks of what we call off-the-charts heat conditions, which are when the combination of temperature and humidity falls above the national weather services heat index scale,” she said. “What that means is that we can’t even calculate a heat index to reliably warn people about how dangerous it is.”

St. Louis

St. Louis is expected to have warmed by almost 10 degrees fahrenheit, a transformational change in the climate of the city. Rising temperatures could provoke a spike in violent crime—when people are hot, research shows, they tend to feel more aggressive.

By the end of the century, St. Louis will endure around 80 days per year where the heat index is above 100 degrees—compared to just 11 days at the end of the 20th century, according to Kristy Dahl, a climate scientist at the Union of Concerned Scientists.

“It’s really striking because historically those off-the-charts conditions have only occurred in the Sonoran desert region of the US, the California-Arizona border,” Dahl said.

In addition to extreme heat, the city will also endure severe drought, punctuated by the occasional supercharged rainstorm. The kind of downpour that currently strikes the Midwest around once every five years will hit around once every year or two. The most severe storms—the kind that currently show up once every 20 years—now arrive once every six or seven years.

Heavy rainfall will lead to flooding, and floodwaters will mix with raw sewage, helping to spread bacteria. Rains will also swamp homes and businesses, offering a place for mold to grow.

San Francisco

By now, San Francisco is projected to have heated up more than seven degrees fahrenheit on average. The extra heat will mean many people will be spending more time outdoors, potentially leading to a spike in violent crime.

The state will be mired in lasting drought. Wildfires could consume around four times as much of the Sierra Nevada as they do today, as well as forests closer to San Francisco, endangering locals.

The Bay Area is expected to have seen more than three feet of sea level rise. The San Francisco and Oakland Airports will be completely underwater. Across the bay, coastal flooding will inundate parts of Alameda. Low-lying areas on the south end of the San Francisco Bay will also be flooded, including some of San Jose.

A visualization of how Houston summers will feel by 2100



By the end of this century, temperatures are expected to have warmed close to eight degrees fahrenheit in Houston. In the summer, Houston will feel something like Jeddah, Saudi Arabia, does today. High temperatures will average over 100 degrees fahrenheit during the warmest months.

By making life harder for workers, severe hotter weather will shrink the economy of the greater Houston area by 6%. Extreme heat will also kill hundreds more people each year. Poorer neighborhoods tend to be warmer, in part because they tend to have fewer trees. People who live in those neighborhoods are also less likely to have air conditioners, which will put them at greater risk.

On top of the heat, Houston is expected to have seen close to six feet of sea level rise by 2100. Waters encroach on the east side of town near the water, where oil refineries and chemical plants could continue to service our catastrophic addiction to oil and gas. Routine flooding of these facilities may cause dangerous explosions and potentially release toxic chemicals into the air.

Much of the city, however, will stay safe from the encroaching sea. That means Houston could absorb hundreds of thousands of new residents by 2100—people who were driven from Miami and New Orleans by ever-worsening coastal floods.

St. Louis

By the end of this century, St. Louis is expected to have warmed by roughly 11 degrees fahrenheit. Winter will scarcely look like winter. Summers will have gone from hot to unbearable.

During the hottest months, it will be so scorching that it will be dangerous to go outside for much of the day. People will depend more on air conditioners to stay cool, leading to bigger electric bills. Elderly people, particularly those who can’t afford to run an air conditioner, will face the risk of heat stroke and death.

The intense heat will take an immense toll on the local economy. Farms in Missouri and southern Illinois could see yields cut in half, ruining livelihoods.

In St. Louis itself, experts project that heat will stifle productivity by making it too hot to work. This could help cut the city’s economic output by around 8%.

San Francisco

By 2100, San Francisco is expected to have heated up by more than eight degrees fahrenheit on average. It will be hot and dry. Snow will be hard to find in the Sierra Nevada. By 2100, the mountain range will see two thirds less snow than we see today, depriving San Francisco of a much-needed water source.

Seas will have risen four feet, projections say. Large parts of Alameda will be underwater. Hunters Point will have flooded, as well as much of Mission Bay. And flooding won’t be limited to San Francisco.

Sea level rise could flood the homes of 13 million Americans by the end of the century, leading to a massive exodus from many coastal areas. By one estimate, rising seas in places like Oakland, Alameda, and San Mateo could spur close to 300,000 residents to move to inland cities in Arizona, Texas, and New Jersey. It is the poorest neighborhoods that will be the most vulnerable to floods.

Editor’s note: This story is based on RCP 8.5, the so-called “business-as-usual” emissions scenario that assumes that Earth will continue to heavily rely on fossil fuels as the global economy grows. Per Nexus Media, “As we are currently doing virtually nothing to stop climate change, RCP 8.5 is a pretty good predictor of what’s going to happen over the next couple of decades. Part of that is because it will take a while for the climate to reach a new equilibrium, so even if we stopped polluting now, the planet would continue to warm for decades.” It looks at a sea level rise of six feet, on average, globally, based on the findings of this widely-cited 2014 study.

Climate change is raising quite the stink in Florida

Waste could contaminate Florida's water as seas rise

Play Video

Waste could contaminate Florida’s water as seas rise 03:54

(CNN)A major UN report released this week shows the sea level is rising around the globe, which means people who live in coastal cities face real risks from losing their property, and in some cases their live, to the rising ocean and the intense storms these warmer waters bring.

And it will make it harder for more than 60 million people in the United States to flush their toilets.
About 1 in 5 US households rely on septic systems, according to the US Environmental Protection Agency. It’s a type of sanitary system that has worked since ancient Egyptian times, but the climate crisis and septic systems don’t mix, studies show.
These systems will be incredibly vulnerable to sea level rise and heavy rains. The climate crisis has brought both. In areas with drought, it may also be difficult to get the volume of water needed to keep the tanks functioning, studies show.
Many systems are clustered in coastal areas that are already expecting sea level rise, including around Boston and New York. Nearly half of New England homes depend on them.
Florida also has a disproportionate share. It’s home to 2.6 million systems, or about 12% of all the septic systems in the country, the Florida Department of Health estimates. Miami-Dade County alone is home to more than 105,000 septic systems.
“Sea level rise is not a registered voter. It doesn’t have a party. It’s something that is going to affect everyone,” said Rebeca Sosa, vice chairwoman of the Miami-Dade County Commission, who spearheaded a study on septic tank vulnerability in the county.
She knows it’s not a glamorous political issue, but with a lot of her residents living on Social Security checks, they’re not going to have the extra funds to deal with the issue.
“Our job right now is to make sure that we make the state and the federal government understand … that we need help, so we can help those who are not going to be able to pay to have sewer lines.”
A county report predicts that within the next 25 years, 64% of the tanks could break and need repairs every year. The report found there are likely 1,000 properties already failing under current conditions.
That’s bad news for residents, but news that will keep some workers busy.

‘Contamination is a real possibility’

When Jason and Brittnie Nesenman were high school sweethearts, never in a million years did they picture themselves standing where they are today: Together, hovering over someone else’s poop.
Jason and Brittnie Nesenman have a lot of extra work fixing septic systems that are vulnerable to the climate crisis.

Jason gets a better angle on a bright blue corrugated hose as Brittnie oversees the operation. The hose runs from their tanker truck, painted with their company’s colorful slogan, “We love your stinkin’ business,” into a septic system. Workers concentrate as they move boards and branches. Together, they clean the tank dug into the side yard of a million-dollar home.
Brittnie shakes her head and laughs, as she describes the fortuitousness of Jason’s decision to start Jason’s Septic Inc. 15 years ago. It certainly didn’t feel that way at the time.
“I was pregnant when Jason came home and told me he quit his job working for a local plumber. I actually gasped,” Brittnie said. “I was a massage therapist. We had no money.”
It may not have been the most romantic gesture when Jason swapped his beloved classic car for a septic draining tanker truck, but it gives the couple a sunny future at a time when the climate crisis darkens Miami-Dade County’s doorstep.
The systems need a certain level of unsaturated dirt to work, but the dirt is disappearing as the sea level is rising.
“With the sea level going up, the water table has risen up,” said Jason.
With a sewer system, he explains, water is whisked away to a water treatment plant.
With septic, the dirt around the tank filters out the contaminants. You flush your toilet, the waste fills a tank on property. Bacteria breaks it down. The heavier material falls to the bottom of the tank. Eventually, the effluent goes into underground pipes and gets released into the soil.
Septic tank repair workers flush out a septic system in Miami.

The higher water table is eating away at all that dirt.
“Everything floats downhill, if there’s no more downhill and you’re in the water, it’s just not going to work,” Jason explains. “So the systems, the older systems aren’t lasting as long.”
No soil means no filter, and no filter means contamination, Jennifer Cooper concluded in her 2016 study titled “Hell and High Water: Diminished Septic System Performance in Coastal Regions Due to Climate Change.”
“The combination of sea level rise and the wetter conditions and warmer temperature is going to be a problem for these systems, for sure,” Cooper said.
Rachel Silverstein, the executive director for Miami Waterkeeper, a nonprofit that fights to protect South Florida waters, eyes the area’s septic systems with real concern.
“Contamination is a real possibility,” said Silverstein. Broken septic systems mean when it floods people will be wading through waste that can make them sick.
If untreated sewage gets into area waters, it can create algae blooms and other ecological problems.

‘This is not a third-world country, this is Miami’

Even on sunny days, Miami is seeing flooding caused by the lunar orbit, which causes seasonal high tides, and what some scientists believe is rising sea levels due to climate change.

As he drives a golf cart from his tiny house real estate office to his lofted modern home, Marcelo Fernandes points to parts of his neighborhood road that flood.
Fernandes, a developer who sells homes in the area, says he has seen more floods due to high tides, even on days with clear skies.
His neighborhood is on septic. He’s worried about the sewage that will be in those flood waters when these septic systems break. Studies show this is a real threat to human health and to drinking water.
“When we are talking about flooding, we are talking about walking around in sewage, it’s bacterial infested sewage,” Fernandes says with disbelief. “This is not a third-world country, this is Miami. This shouldn’t happen.”
Doug Yoder, the deputy director of the Miami-Dade Water and Sewer Department, says the county has been strategizing and working on the problem of sea level rise for about 30 years.
With flooding due to sea level rise, the Miami area will have to improve its infrastructure to cope with the high tides.

“This water management system is probably one of the most complex anywhere in the world,” explained Yoder. “We are in a place where the ocean is directly connected to our shallow groundwater system. As sea level rises, which it is clearly doing, it is going to affect our ability to both protect our drinking water supply and protect the built environment.”
The county report estimates it would take more than $3.3 billion to build the infrastructure to connect residential and businesses to the system and to support the additional service that will be needed from pumping systems and move properties to traditional sewer.
“It’s going to require even more than that, because you would also have to tear up the streets, and increase the capacity in our treatment system,” said Yoder.
For residents, replacing a septic system with sewer could cost between $15,000 to $50,000 out of pocket. It’s not an easy bill to pay for many residents and not an easy sell for politicians. Miami Waterkeeper’s Silverstein worries the area isn’t ready to adapt.
“All of the rules and regulations aren’t there quite yet,” Silverstein said. “There’s still a lot of development and people are really just hoping for the best.”
Septic repair tanker trucks could be more common in coastal cities, due to the climate crisis.

‘How do we fix this?’

There are counties in the area that are already working to eliminate all their septic systems in the next decade. Martin County, for example, has about 10,000 systems left to replace. The county is sharing the cost with residents.
New developments there have to be connected to sewer lines. That’s not the case in Miami-Dade County, where there are still new developments being built on septic. Miami-Dade County Commissioner Sosa is introducing legislation to change that.
Sosa has serious concerns about how much this septic system problem will cost her constituents. She has worked with the governor to get funding. She also hopes to get more information to the public about the issue.
“How do we fix this? It’s not easy,” said Sosa.
Even if people have the money, if they live miles from closest sewer connection it may not even be possible to connect, Sosa said, so the area will have to come up with alternatives, like elevating some systems.
Get CNN Health’s weekly newsletter

Sign up here to get The Results Are In with Dr. Sanjay Gupta every Tuesday from the CNN Health team.

“We have to act and we have to act with speed,” Sosa said. “But if we don’t get funding assistance it’s going to be impossible to do.”
Politically, Sosa said it may be hard to find the money for this, but, she said the county’s future depends on it.
“We don’t need people saying ‘We don’t go to Miami-Dade County, because look at the problems they have with the sewer system. Look at the contamination we have with the drinking water,’ ” Sosa said. “It’s of an incredible importance. The drinking water and the safety and health of the people, that has no price.”