California has lost thousands of square miles of farmland and natural habitat to development since the 1980s, and a new report from NumbersUSA argues that immigration-driven population growth was the dominant factor behind the expansion.

The report, Paving Paradise: 50 Years of Population Growth in California, examines changes in the state's developed footprint and the consequences of accommodating a population that roughly doubled over the past five decades. According to the analysis, California converted more than 3,740 square miles, or nearly 2.4 million acres, of agricultural land and natural habitat into housing, roads, commercial development, and other developed uses between 1982 and 2022.

NumbersUSA's analysis attributes 91% of that land conversion to population growth, with the remaining 9% attributed to Californians using more land per person. The organization argues that the finding demonstrates that even efforts to make development more compact cannot completely eliminate the environmental impact of adding millions of residents.

The report points to consequences extending beyond the loss of open space. Researchers examined pressures involving traffic, housing, water supplies and agricultural land as California's population expanded.

The loss of farmland is particularly significant in the Central Valley, one of the country's most productive agricultural regions. NumbersUSA says urban expansion around communities including Fresno, Bakersfield and Sacramento has converted agricultural areas to residential and commercial development. In Imperial County, another major agricultural region, the report found that cropland declined substantially between 1982 and 2022 while developed land more than tripled.

Traffic is another major concern highlighted by the study. A survey of 1,030 California likely voters commissioned by NumbersUSA and conducted by Noble Predictive Insights found that 78% were concerned about growing commute times, while 80% expressed concern about the state's future water supply. Ninety-three percent said protecting remaining farmland, forests, wetlands and open spaces from further development was important.

Jim Robb, vice president of NumbersUSA, argued that the state's population growth has placed increasing pressure on existing infrastructure.

“There’s been a huge amount of population growth since we were looking at California last,” Robb said, pointing specifically to longer commutes and persistent highway congestion.

California has also experienced a significant domestic population outflow in recent years. NumbersUSA's research notes that nearly 10 million people left the state for other states between 2010 and 2024, although international migration offset much of that decline. The organization's analysis argues that high housing costs, traffic, and other quality-of-life concerns have contributed to residents leaving.

The report's findings are part of NumbersUSA's broader argument that federal immigration policy has consequences at the state and local level. The organization contends that states cannot independently control national immigration levels even when population growth increases demand for housing, water, transportation, and land.

The study does not argue that every environmental or infrastructure problem in California is caused by immigration. Rather, its central finding is that population growth was responsible for the overwhelming majority of the land conversion it measured.

California's experience has therefore become a case study in the debate over how population growth, immigration, development, and environmental preservation interact as the state attempts to accommodate millions of additional residents.