Our Studies
NumbersUSA’s two decades of sprawl studies – cited in scholarly literature over a hundred times in over a dozen languages – have explored the role of population growth, immigration, and development choices by government, business, and individuals.
Two Decades of NumbersUSA Studies and Reports on Population Growth and Urban Sprawl
2024 Greater Yellowstone – An Ecosystem at Risk
2024 NEVADA No. 1 Sprawl
2024 North Carolina Love Hurts
2023 Illusion of Endless Texas Habitat
2022 From Sea To Sprawling Sea (49 states)
2021 A Thirsty Arizona
2020 Californication of Oregon
2017 Paving The Piedmont (GA, SC, NC)
2017 Texas Urban Triangle
2014 Vanishing Natural Florida
2014 Vanishing Open Spaces (48 states)
2003 Sprawl In Minnesota
2003 Outsmarting Smart Growth (48 states)
2001 Large U.S. Cities
2000 Sprawl In Florida
2000 Sprawl In California
Quantifying the Factors in Sprawl
Our first study, Sprawl in California (2000), broke new ground by quantifying the roles population and consumption played in what was then the most sprawling state in the nation. The study found that most anti-sprawl efforts ignored the No. 1 factor in California’s loss of open space: population growth. The study’s authors Leon Kolankiewicz and Roy Beck warned that if California failed to tame sprawl, the issue would eventually resolve itself in other ways.
“Aggravated traffic congestion alone,” they wrote, “has the potential to make Californians miserable enough to consider fleeing the state for some semblance of ‘greener pastures’ in other less crowded western states.”
California has been the No. 1 destination for immigrants for the past three decades. And yet in every year except for 1999 and 2000, more Americans have moved out of California than moved in.
From Sea to Shining Sprawling Sea
NumbersUSA’s sprawl studies document the loss of farmland and habitat throughout the contiguous forty-eight states, plus Hawaii. Results vary considerably from state to state and from county to county within a state. But the national overview provides stark contrasts:
The studies find that in many counties population growth is mainly driven by local decisions and conditions that attract net migration of Americans moving in from other states and counties, However, federal policies that have increased average annual immigration by 300-400% since the first Earth Day in 1970 are responsible for nearly all national population growth.
The federal government’s failure to respond to sustainability recommendations of several national commissions has forced extra population growth and allowed urban sprawl to continue to exact a powerful toll on biodiversity, natural habitat, productive farmland, and human quality of life, one acre at a time, across America. The results have global consequences, but are felt most acutely in the local areas where the relentless loss of open space occurs as soils and the wild flora and cultivated crops they support are replaced with concrete, asphalt, steel, and plastic.
Our Most Recent Sprawl Studies
Nevada No.1 Sprawl
No state eliminated natural habitat and farmland at a faster rate than Nevada during the latest 35-year period covered by available federal data (1982-2017).
The 153% increase in sprawl (nearly 500 square miles of newly developed land) was more than twice as fast as all but a dozen other states.
North Carolina – Love Hurts
People in more populous countries and states look at North Carolina’s mountains, coastal plains, lower housing costs, and its bucolic farms, towns, and human-scale cities — and they love what they see. They’ve been proving it for decades with convoys of moving vans entering North Carolina in numbers experienced in only a few states.
But this demonstration of love has its costs. To accommodate all the newcomers has meant diminishing and eliminating many of the attributes that drew people to move to the state in the first place, according to our study of the most recently available government land use data through 2017.
CALIFORNICATING IDAHO
As more and more people move to Idaho, the state is taking on the sprawling characteristics of the densely populated countries and states they have fled. Californians are the No. 1 source of Idaho arrivals as they leave their coastal state in even larger numbers than the hundreds of thousands of foreign immigrants who continue to settle there.
Most Idahoans remain strongly supportive of the state’s agricultural tradition and preserving productive farmland. But despite “better built” efforts, Idaho farmlands and agriculture will continue to be faced with tremendous development pressure from demographic forces as long as the state’s rapid population growth continues.
ILLUSION OF ENDLESS TEXAS HABITAT
Texans are perhaps more aware than most Americans of how immigration policy – set by Congress, hundreds of miles away from the dwindling Blackland Prairie of Eastern Texas – plays a determining role in the congestion and sprawl they experience in their daily lives. A majority of Texans support reforms to international migration that would slow or stop population growth in their great state.
Most Texas voters say their lives are already more crowded, and that the projected addition of 14 million more residents by 2060 would make their lives worse. For centuries, people have been drawn to Texas by its expanse and available land: “Miles and miles of Texas…” as the song goes — not “miles and miles of megacities.” At some point, a place loses its luster and people no longer view it as an attractive destination. Texans, like Americans in many parts of the country, are wrestling with that.
DISAPPEARING COLORADO
Anti-growth is a 90-10 voter issue in Colorado that almost no elected, corporate, or civic leaders in the state are talking about. Nine out of ten Coloradans desire a future in which far fewer people move into the state. State leaders, however, promote density and population growth, which is projected to turn the Front Range into a “mega-city” or megalopolis by 2050. The Front Range, once famous for its views of the awe-inspiring, snow-capped Rocky Mountains, is now more infamous for its smog, traffic gridlock, and views of never-ending subdivisions.
FROM SEA TO SPRAWLING SEA (49 states)
The “30 by 30” movement to protect 30% of U.S. natural habitat from development by 2030 is being fatally undermined by existing federal immigration policies that are forcing continued mass population growth. At the same time, most Americans are living a more congested lifestyle while denied the psychological and physical benefits of nearby natural areas they once could access but which have recently been eliminated.
Despite numerous national and local commitments to restrain urban sprawl since the 1990s, nearly 18,000 square miles of natural habitat and farmland were cleared, scraped, paved, and built upon during just the most recent 15 years of reported federal data collection. (2017 National Resources Inventory, Summary Report – September. Table 1.)
Roughly two-thirds of all open-space destruction was related to population growth. And one-third of the destruction was related to all the factors combined that caused an increase in per capita land consumption that occurred in some counties.
While this developed or urbanized land is but a relatively small fraction of the overall land area in the United States, it is crucial to recognize that open, undeveloped, unpaved, relatively unpopulated lands aren’t just languishing unused; rather, they provide tangible benefits and often intangible but no less important ecosystem services to populous, built-up areas (i.e., those places that are developed and populated).
In other words, those open spaces aren’t “wasted” or “yearning for development.” They already furnish goods and services to the American populace. It is a fallacy of the highest order to delude oneself that open lands could all one day be developed with impunity to accommodate ever more people. Where will the cropland that feeds these hypothetical multitudes, or the timberlands that provide wood to build their homes, come from if these resources have been replaced with pavement and subdivisions?
A THIRSTY ARIZONA
In Arizona, at the epicenter of the arid American Southwest, the shortage of water is much more acute than that of land. Arizonans depend on both surface and groundwater for irrigated agriculture and urban land uses. And they compete with other Southwestern states for the Colorado River’s shrinking flows. Water levels are at historic lows in the Colorado’s Lake Mead, which is the largest reservoir in the entire United States. In a survey conducted along with our study, Arizonans unequivocally favored keeping water in natural streams and rivers, where it provides aquatic habitat and ecosystem services, rather than diverting it to accommodate still more population growth.
The Grand Canyon State boasts not just the iconic Grand Canyon of the Colorado River, a true geological wonder of the world. It also boasts expansive deserts, mountains, forests, and cherished dark skies with stunning views of our Milky Way galaxy and beyond.
All of these, however, are threatened by Arizona’s explosive population growth, development, and sprawl, which have transformed much of the state since the 1970s. Most of the increase in Arizona’s unsustainable numbers comes from migration, both domestic and international. As a next-door neighbor to California, Arizona has borne the brunt of the once-”golden” state’s immigration-driven overpopulation, as ex-Californians have fled the state’s traffic, overcrowding, crime, and unaffordable housing.
CALIFORNICATION OF OREGON
Perhaps no other state takes protection of open space as seriously as Oregon. Its efforts to tame sprawl date back half a century. And yet, the Beaver State’s urban growth boundaries have been no match for the urban requirements of a growing population.
Yet as more and more of the Willamette Valley and Rural Oregon succumbs to development — chipped away and clogged with roads, vehicles, people, facilities and infrastructure — at some point it will not be possible to maintain this rapid rate of sprawl simply because other critical land uses — e.g., high-value crop and pastureland; national and state parks, forests, and wildlife refuges; mines; watersheds and reservoir buffer zones; utility corridors; U.S. military bases and arsenals — will represent a larger and larger fraction of the remaining undeveloped land.
PAVING THE PIEDMONT (NC-SC-GA)
The Piedmont region of Georgia, North Carolina, and South Carolina is the geologic province that borders the Appalachian Mountains to the west and the coastal plain to the east. It is known for its gently rolling hills and mixed habitats of pine and broadleaf woodlands, as well as its extensive farmlands. Unfortunately, in recent decades, it has also become known as the site of an “emerging megalopolis” that may someday rival the other major eastern megalopolis running from Washington, DC up to Boston, and encompassing Baltimore, Philadelphia, Wilmington, Delaware, New Jersey, New York City, and Connecticut.
The emerging Southern Piedmont Megalopolis runs from Atlanta – already the most sprawling city in the entire nation – up through Richmond, Virginia. Its swelling and stretching tentacles already ensnare Athens, August, Columbia, Charlotte, Durham, and Raleigh, as well as many smaller burgs destined to be swallowed up if current and projected population growth and land development trends are allowed to continue.
VANISHING NATURAL FLORIDA
The only state to add more people and lose more rural land to sprawl in the 21st century to date than Florida is Texas. Florida is renowned for its exotic natural habitats and its unique wildlife – manatees, panthers, dolphins, alligators, crocodiles, eagles, storks, flamingos, and spoonbills – among many others. Both wildlife and habitats such as the Everglades – the fabled “river of grass” – are threatened by too many people and too much development. Emerging threats include invasive species, sea level rise, die-off of coral reefs, red tides, and more ferocious and frequent hurricanes. All of these are aggravated and exacerbated by too many people and too much development. NumbersUSA has dedicated two of its sprawl studies in the last two decades to analyzing the sources and solutions to Florida’s sprawl.
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