Gentrification is to real estate what climate change is to the environment. Species migrate into new habitats, and the terrain, be it commercial or natural, changes. All the new money that flows into a neighborhood has the same effect as the greenhouse gases we pump into the atmosphere: prices rise just as temperatures do.
Both are problems of abundance, and expressions of demographic pressure. They are global trends made local: a coastline changes or a favorite store loses its lease. The interconnectedness of the world means that inevitably change will arrive at our doorstep.
There is, however, one significant difference. Man-made climate change is a new phenomenon, but gentrification has been with us for a long time. Tour any great city and at some point the guide will tell you that the fashionable district in which you are standing had a far rowdier past.
These days the process often follows this pattern: first the hip, then the foodies, and finally the real estate agents. To rephrase Caesar's summary of a conquest: I came, I ate, I moved in.
Gentrification requires not just an infusion of wealth, but vulnerable people and neighborhoods as well. The changes may feel abrupt but the conditions that make it possible have been in place for years: disparities in income and education, barriers to homeownership and capital accumulation, the shortage of permanently affordable housing.