Gentrification and demographic change in American cities is certainly a perennially popular topic. At least for me. But when we talk about, for example, a city getting whiter, or less white, we're really talking about changes in the sizes of two distinct populations--the white population and the non-white population--with little quantitative or historical reason to assume those populations are influenced by the same things.
Moreover, looking only at the change in a city's white percentage might obscure important changes in both populations. Imagine a city where both the white and the non-white population doubled, or a city where both the white and non-white populations dropped 20%. Two very different cities with two very different dramatic shifts, but neither would show any change whatsoever in its population's white percentage.
Those are extreme examples. but there are cities that became whiter because both the white and non-white populations dropped, the latter at a higher rate, as in New Orleans or Chicago, or because both the white and non-white populations grew, the latter at a lower rate, as in Wilmington, North Carolina.
The below chart attempts to explore these dynamics. Each circle is a CDP with the same ID in both 2000 and in 2013, data being taken from the 2000 Census and the 2013 American Community Survey 3-year estimates. The y-axis shows the growth rate of the non-Hispanic white (NHW) population, while the x-axis shows the growth rate of the non-NHW (Hispanic or non-white) population, with each axis' position corresponding to no change. Cities to the left of the diagonal line had their NHW populations grow more quickly or shrink less quickly than their non-NHW populations and shifted whiter; cities to the right of the diagonal line went the other way.
(Note: Of 2013 Census-Designated-Places with 3-year estimated population over 100,000, Miami Gardens, FL and Centennial City, CO were incorporated after 2000, while the Census' definition of the Urban Honolulu CDP has changed since 2000, so neither are in the above chart.)
As you can see, at least according to official estimates, a great deal of population growth, in nearly CDP, was driven by non-whites. Most of the very largest cities had little growth, or moderate decrease, in non-Hispanic white populations--including such supposed growth dynamos as Houston, Texas or Phoenix, Arizona. Washington, Fort Worth, Austin, Denver, Seattle, Charlotte, and Portland stand out as large cities with fast non-Hispanic white growth, although all but Denver and Washington had even faster Hispanic and non-white growth.
Very few CDPs actually grew whiter from 2000 to 2013. But the exceptions are interesting: New Orleans, Louisiana. Glendale, Oakland, Pasadena and Berkeley, California. Atlanta, Georgia. Arlington and Richmond, Virginia. Wilmington, North Carolina. Charleston, South Carolina. Washington, DC. Denver, Colorado. St. Louis, Missouri, by a tiny bit. (Louisville consolidated with Jefferson County in 2003, hence its enormous growth and large increase in non-Hispanic white percentage.)