Energy Use, CO2 Emission and Immigration
Energy consumption is a factor of both per capita use and population size. Population size includes the issue of immigration. U.S. energy consumption and the resulting environmental impact of the production of greenhouse gasses has been steadily increasing in total amounts even though per capita consumption has been decreasing.
U.S. energy consumption increased by about 34 percent from 75.8 quads (quadrillion  BTUs) in 1973 to about 101.5 quads in 2007. Over this same period, per capita energy consumption decreased by 6.4 percent. The reason for the increase in energy consumption is due to the 43.1 percent increase in the U.S. population.
The role of immigration in population increase and its role in increased energy consumption results from the growing rate of immigrant admissions (legal immigration) supplemented by large scale illegal immigration and the growing admission of long-term nonimmigrant workers. From 1975 to 2007, the United States admitted 27 million immigrants. Thus direct legal immigration accounted for 31.5 percent of the U.S. population increase during this period. The share of population growth attributable to immigration is still higher when illegal immigration estimated at 13 or more million persons and long-term foreign workers arriving at more than one million per year and staying as long as 5 or 6 years are included. And the children born to these immigrants and nonimmigrants add still more.
The pattern of increased energy consumption and population growth may be seen also when examining sectoral use. In the residential sector, consumption increased by 44.7 percent between 1973-2007 while per capita consumption remained virtually unchanged. By contrast, in the industrial sector, energy consumption was virtually unchanged between 1973 and 2007 while per capital consumption actually declined about 30 percent as industry installed more energy efficient production equipment or moved offshore. When per capita energy consumption data in the commercial and industrial sectors are added together, the total declined by about 16 percent while total energy consumption in these two sectors increased from 42.2 quads to 50.9 quads (21%). Thus, once again, this 8.7 quad increase may be attributable entirely to population growth.
In the transportation sector, there was a 9 quad increase in energy consumption between 1974 and 2007 as well as a 9.1 percent increase in per capita energy consumption, a fact likely related to more cars per capita, increased purchase of less economical vehicles such as sport utility vehicles [SUVs] and Humvees, as well as the extended use of older, less fuel-efficient cars by population segments with limited means. Per capita motor gasoline consumption in the U.S. increased by 7 percent between 1974 and 2005 despite major improvements in the fuel efficiency of new vehicles, but total gasoline consumption increased over the same period by 53 percent. The driving factor behind gasoline consumption is vehicle-miles, which in turn is driven by population growth. Total vehicle-miles for passenger cars, motorcycles, light trucks and SUVs rose approximately 113 percent between 1974 and 2000. This reflects the fact that as the population of an urban region grows, the urbanized area increases in size, and the residential areas are almost always on the periphery of the urban region. Therefore commute distances are increased. Secondly, population growth has caused property values near some urban centers to rise dramatically. People with modest incomes who have been priced out of the housing market in these urban centers have been buying homes in small towns that, in some cases, are located considerable distances from their places of employment.
Looking at the total energy usage, population growth is again revealed as a primary factor in the overall 34.1 percent increase in energy consumption over this same period because overall usage per capita decreased by 6.3 percent.
As the United States considers policies to curb greenhouse gas emissions particularly carbon dioxide (CO2 ) the impact of immigration on emissions levels cannot be ignored.
Suppose that U.S. accepted the Kyoto Protocol target of reducing energy consumption by 7 percent from the 1990 level by 2012, i.e., to 78.4 quads. Per capita energy consumption would have to fall to 245 million BTUs, which represents a 37 percent reduction from projected 2012 consumption based on current trends. A required reduction in energy consumption of this magnitude would necessitate enormous lifestyle changes for Americans and cause serious economic dislocations. Restrictions on CO2 emissions would translate into higher manufacturing costs for U.S. industry regardless of whether these reductions were achieved through taxes, fuel switching, and installation of more efficient equipment, trading emissions credits, or other means. U.S. industry would be disadvantaged in comparison to manufacturers in both Europe and Japan which do not have a similar population growth and in undeveloped countries which have high population growth but no requirement of CO2 emission reduction.
Finally, it is important to note that immigration is the principal reason the natural rate (births less deaths) of population increase is so much higher in the U.S. than in Europe. The 2000 U.S. Census data show that the Hispanic or Latino population segment, which has surged as a result of immigration, accounted for 12.5 percent of the population but 18.7 percent of all live births, The Census Bureau estimates a total fertility rate (births) of 2.049 for women of all races and 2.921 for women of Hispanic origin 42.3 percent higher.
The increase in energy consumption as a result of population growth shows clearly that the United States would not be able to achieve meaningful CO2 emission reduction, such as called for in the Kyoto Protocol targets, without serious economic and social consequences for American citizens unless population growth is sharply reduced. This necessitates a sharp curtailment of immigration the principal factor in population growth. Failure to address the immigration issue is only rendering the energy problem more intractable. The longer the United States continues to grow at a rate of about 3 million people per year, the more precarious will become the existence of each of us and our children and the sooner that undesirable and traumatic major forced adjustments will arrive.