In December, the news arrived that the District’s population had increased by 16,000 people in a little over a year. The Post’s story called the change “remarkable” and spoke of “a turnaround in the city’s fortunes and image.” But it left me wondering: Who’s moving in? And who is leaving? From my view on Irving Street NW, I think I have a pretty good guess.

Here’s what I see: long-term African American residents leaving the city, and not by choice. Their old neighborhoods are being taken over by young, white professionals who are the beneficiaries of educational and social opportunities that this African American population never had. Many of these African Americans raised families in the old brownstones in my neighborhood, but they rented from absentee landlords who now have been more than happy to sell out to developers. A historically disadvantaged people has been disadvantaged once again.

Those of us who own our houses are not immune to these pressures. These developers, so often young and white themselves, approach us and ask if we want to sell. They make lowball offers that assume we are stupid.

This is not a real estate story. It’s a social movement. According to the Census, the black population of the District dropped by more than 39,000 from 2000 to 2010. A Northwest neighborhood that was more than 90 percent black a decade ago has undergone a “radical shift” in its racial makeup. The newcomers arrive in their mid-to-late 20s, college degrees in hand, ready to conquer the world; they start by taking over the old black neighborhoods in D.C. The Post reported that these people have “zero interest in the suburbs.” There’s plenty of irony there, given that the move to the suburbs was a social migration exacerbated by fair housing laws and what most whites saw as forced integration. Now it’s happening in reverse, but I guess it’s all supposed to be okay if you call it “cool” and “ultra-hip.”

I talked to the mom of a black family on another block of Irving Street. They’ve owned their house since the early 1980s. Both parents are college graduates and are professionally employed, as am I. They raised two sons in that house, one a recent college graduate and the other about to finish up. They are now the only black family on her block. With one exception, she says, she would describe her new white neighbors’ behavior toward her family as “hostile.”

I can relate. When we rehabbed our rowhouse in 1990, my block was filled with black families. I count two now.

For me, there’s another layer of irony to these changes. I have always liked gentrification — young people moving into the city who wanted to be part of a multicultural, diverse neighborhood. But that’s not what’s happening. Watch how these newcomers interact with the indigenous population.

When it snows, I shovel our walk and then the sidewalk across the street for a little old lady who lives alone. The winter before last, one of the new neighbors walked up to me and asked how much I would charge to shovel his walk, too. Think of it: He was asking if I wanted to earn some pocket change while I was wearing my $500 Polo jacket. Good news, though: I didn’t hit him with the shovel.

Last year, one of the newbies got stuck in the snow. I helped push him out. As soon as he was free, he jumped out and offered me $5. Did it cross his mind that the black man giving him a hand was his neighbor and was just being neighborly? I told him I was sorry I helped him and walked away.

And apparently there is a memo I didn’t get. The one that says: “Whenever you see a non-white person in the neighborhood, be sure you strike an immediate hard look on your face to be sure they know you are not friendly.”

What are they thinking? Do they wonder who lived in these houses before the developers ran them out? What the hell do they think racism is anyway?