Rising Seas Could Swell Arizona’s Population

Arizona’s low taxes and living costs, friendly culture, arts scenes and easy access to outdoor activities make it an appealing state in which to settle.

And in decades ahead the state’s draw as a new home could be boosted as seas rise and oceans warm, forcing coastal residents to deal with fallout like strengthening storms, floods, mudslides and other disasters.

This was the first of two stories produced and published in partnership with the Arizona Daily Star for World Oceans Week. Read the second story, “Antarctic Ocean Discovery Warns of Faster Global Warming”, by Star science and higher ed reporter Mikayla Mace.
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“We see natural disasters all over the world; but to be very close to one, and experience the utter helplessness, as well as the repeated evacuations, is very, very stressful,” says Jenni Aguilar, who moved her family to a four-bedroom house near Tucson from California on Memorial Day.

Aguilar says the high cost of living in California already had her considering a move from the beach town of Carpinteria when heavy winter storms followed wildfires, causing mudslides that killed 21 people and convinced her to head east.

“We started looking here, and it just worked out,” said Aguilar, who moved to Milagro, a cohousing community just outside city limits, with her husband and two sons. Her daughter, future son-in-law and grandchild are moving in this weekend.

“We’re a pretty resilient family,” said Aguilar.

There are some adjustments to be made in a new desert climate. Jenni Aguilar collects ice in the kitchen of her family's new home just outside Tucson, AZ.
Credit: Ron Medvescek / Arizona Daily Star

Research published last year included Pima County among the top 9 percent of counties into which Americans are likely to move after being forced from their homes by another coastal climate threat — sea-level rise.

The study projected sea rise could bring 10,000 more residents this century to a county where about a million currently live.

Among the states, Arizona ranked sixth as a likely destination.

“People are already making those moves from coastal areas into Tucson,” said University of Georgia geographer Mathew Hauer, author of the study, published in Nature Climate Change. “There’s a lot of different reasons as to why any one person might make that move. Sea-level rise might be the straw that breaks the camel’s back, if you will. It might be that little push that people need.”

Rising temperatures are melting ice, while ocean water is expanding as it warms. Ice sheet modeling indicates Antarctica’s ice sheet could crumble at a quickening pace as warming water and air gnaw at its edges, hastening sea rise. A federal climate science assessment last year concluded seas are “very likely” to rise this century by one to more than four feet. A worst-case scenario would see some American shores inundated with more than 10 feet of sea-level rise during that period.

Most of the heat trapped by greenhouse gas pollution goes into the oceans. As well as influencing migration by raising the seas, that ocean heat fuels stronger storms and monsoon rain — both of which reach into Arizona. And by moving heat and heat-trapping carbon between the water and the atmosphere, ocean conditions affect inland temperatures.

Migration hard to predict

Complicating efforts to predict how Arizona will be impacted by migration from rising seas, experts say its ability to accommodate growth could wither under other impacts from climate change — rising temperatures and worsening water shortfalls.

The Tucson skyline.
Credit: Andrew/flickr

Research published last month in the Journal of the Association of Environmental and Resource Economists found that the population west of Texas, Colorado and Montana could swell more than a tenth during the next 50 years because of migration within the U.S. from climate change, largely from the South and Midwest.

Previous research by the same economists showed extreme heat, on the other hand, can drive away residents, which could affect populations and economies in cities like Tucson.

“If it’s too hot for you in Tucson, the college graduates are more likely to move out, rather than low-income or people who are less mobile,” said one of the researchers, Qin Fan, an economist at California State University, Fresno.

Perhaps more than anything else, water shortages could hobble growth in Tucson — even without climate change, which is projected to make them worse.

“The Southwest, ever since the Second World War, has experienced this absolutely explosive urban growth, and that growth has been based on cheap water and cheap electricity,” said Thomas Sheridan, an anthropology professor at the University of Arizona. “There’s no major new source of water on the horizon.”

Rising seas

Closer to America’s shores, some streets flood now even in fine weather, with high tides overtopping coastlines that were developed when local water levels were more than a foot lower.

Rising flood insurance rates are adding to coastal housing costs. Homes along some of the most flood-prone roads have lost much of their value, while damaged houses left vacant following storms blight neighborhoods along the Gulf Coast and up through the Mid-Atlantic.

“We’re going to get to a threshold,” said David Wrathall, a geographer at Oregon State University investigating future migration from sea-level rise. “There will be low levels of migration, and then suddenly there’s going to be these moments where lots of people are going to come into the system all at the same time. Not just from one location, but from lots of coastal locations simultaneously.”

Flooding in Fairmount Avenue near Arizona Avenue at high tide during a storm.
Credit: Ted Blanco/Climate Central

A major uncertainty in all climate research is future pollution rates. The more pollution that’s released from fossil fuels, farming and deforestation, the more severe the impacts from climate change will be.

Governments from Tucson to China are starting to take steps to slow warming and adapt to it, even as the Trump administration dismantles federal climate programs.

Hauer’s research considered how many people in coastal U.S. counties could be forced to find new homes if high levels of pollution this century cause seas to rise six feet.

Then he modeled where they might go.

Hauer’s research showed 13.1 million Americans would be at risk of losing their homes by 2100 — when today’s toddlers could be old and vulnerable. The figure included more than 2.5 million people leaving Florida and nearly 1.5 million arriving in Texas.

Other popular destinations may include counties in Georgia, North Carolina and Pennsylvania as well as Arizona.

The research didn’t account for effects of migration from low-lying and vulnerable places outside the 50 states, like Puerto Rico, the Marshall Islands, Bangladesh and the Yucatan Peninsula, where rising seas and strengthening storms will drive countless more to seek new homes.

Instead, it examined one of the ways that warming could affect the movement of families around the U.S. — which for many is already a familiar process.

“We’ve lived in a lot of places — we’re somewhat semi-nomadic,” said Aguilar, who moved to Tucson after the mudslides.

“I don’t know that a lot of Americans like to call themselves that. But a lot of Americans are that.”

Sea Level Stakes for the Caribbean, in Pictures

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Sea Level Rise Report by Climate Central

Long-term sea level rise set in motion by near-term carbon emissions threatens major coastal cities across the world. Science-based imagery helps show the stakes for the Caribbean.

The first image in each pair below shows projections of post-2100 sea level rise that could be locked in following 4°C (7.2°F) of warming from carbon pollution. This pathway corresponds roughly to business as usual. The second image in each pair shows projections based on 2°C (3.6°F) of warming, corresponding to the upper limit target named in the 2015 Paris Climate Agreement.

Agreement implementation will determine which of these two scenarios the future looks like most.

The projections behind these images come from peer-reviewed research, and a special report describes how these findings are translated into global maps, viewable at Mapping Choices. Maps and imagery for the Caribbean are based on Climate Central's CoastalDEM™ version 1.1, a special high-accuracy elevation dataset that improves over the data originally used.

The images on this page were created by visual artist Nickolay Lamm based on Climate Central’s maps and elevation data, with support from the Inter-American Development Bank. Images for other global locations are available here

The 10 Most Important U.S. Climate Stories in 2017

Following a year of weather extremes, disasters and policy clashes, we asked our readers to help us pick out the most important climate stories from the U.S. in 2017. Here's what you said.


This was a brutal year for hurricanes in the U.S. A trifecta of storms (Harvey, Irma and Maria) battered Florida, the Gulf Coast and Puerto Rico, causing deaths and widespread destruction, driving many from their homes. Climate change is fueling hurricanes by increasing their rainfall, wind speeds, and storm surges. Our World Weather Attribution team was among the groups of scientists that found climate change increased the amount of flooding rainfall from Harvey.


Sea-level rise projections got worse for U.S. coastal communities. New research factoring in the projected effects of warming on Antarctic ice outlined new scenarios for Gulf Coast and East Coast cities, where more than 10 feet of sea-level rise is possible in places this century. Sea-level rise could be kept to less than two feet if we aggressively curb our greenhouse gas emissions, reducing risks and impacts.


The Trump administration worked to reverse climate protections this year, seeking to replace the Clean Power Plan and eventually withdraw from the Paris Agreement. The administration has been removing the phrase “climate change” from government websites and it greenlighted construction of the Keystone XL oil pipeline. All the while, hundreds of thousands of people marched for science and the climate, and states and cities and nations abroad vowed to fight harder to slow global warming.


2017 was the year of Tesla co-founder Elon Musk. From a battery factory in Nevada, to South Australia where his batteries are helping a wind farm provide reliable power, to a new energy grid in hurricane-ravaged Puerto Rico, Tesla has taken the lead in producing batteries for energy storage and to power electric cars. And it has developed new all-electric semi trucks and solar shingles!


California is battling its largest wildfire on record right now, but this wildfire season wasn’t just bad for the Golden State. Wildfires burned more than 9.5 million acres across the U.S., destroying neighborhoods and releasing dangerous smoke pollution. The Western wildfire season is 105 days longer than it was 45 years ago as climate change fuels more and bigger blazes.


2017 is likely to be the third-hottest year on record for the U.S., behind 2016 and 2012. This record heat is particularly astounding considering the absence of an El Niño, which usually boosts global temperatures. If the final data matches expectations, five of the 10 hottest years on record will have come since 2006.


The homes of Americans were destroyed or threatened by extreme weather and rising seas, with the poor hit the hardest. Hundreds of thousands of people had to flee Puerto Rico after Hurricane Maria devastated the island, relocating to Florida and other areas. Thousands more in New Jersey and Louisiana are hoping for federal help as they grapple with the ongoing effects of flooding linked to rising seas and climate change-fueled storms.


Production of clean energy climbed as prices continued to come down. In March, 10 percent of all electricity generated in the U.S. came from wind and solar, with help from Texas (America’s number 1 wind provider) and California (the largest solar producer). Bloomberg New Energy Finance concluded in the summer that solar energy can now be as cheap as power from new coal plants in the U.S.


Your car is contributing to the biggest source of U.S. emissions. Transportation recently overtook electricity generation as the biggest source of greenhouse gases from the U.S., as coal power plants were retired and replaced with renewables and natural gas facilities.


It may be winter right now, but don’t forget about extreme heat, which is the number one weather-related killer. Climate change made a February heat wave across much of the eastern U.S. three times more likely. In June, another heat wave in the Southwest prevented planes in Arizona from taking off. Danger days are surging from Power, Montana to New York City, and a dramatic rise in dangerous heat and humidity will continue in the summertime.