California's population grew by 5 million people between 2000 and 2015 and the state is expected to add another 10 million people by 2050 based on current population projections from the California Department of Finance. However, native born Californians are having fewer children than in the past. Based on U.S. Census Bureau and California Department of Public Health data, the state's overall population growth is being driven by mass immigration and births to immigrants. Please see report showing, for example, the Direct and Indirect Contribution of Immigration to California's Population Growth over a 10 year period. Also, please see recently released U.S. Census projections of the Size and Composition of the U.S. Population: 2014 to 2060. While this level of growth is slightly slower than the immediately preceding increment of 98 million, which took only 37 years to accumulate, it’s hard to fathom how another 100 million people will do anything but erode the quality of life and the natural environment of the U.S.
And, according to a Pew Hispanic Research Center report “Between 2015 and 2065, future immigrants and their descendants are projected to account for 88% of the U.S. population increase, or 103 million, as the nation grows to 441 million." Since California receives more immigrants than any other state immigration and births to immigrants will continue to account for nearly all of the state's population growth.