After 60 years in business, Brennan’s Restaurant is calling it quits next month, with no plans to reopen.

Co-owner Margaret Wade, granddaughter of founder John Brennan, cited a slew of reasons for closing the storied Berkeley restaurant: a looming 25 percent rent increase, global warming, and — somewhat surprisingly — a drop in cocaine use. The news began spreading last week and crowds quickly descended on the sports bar and hofbrau in horror and disbelief.

“We didn’t plan very well for what would happen when word got out,” Wade says. “We were run off our feet.”

She says a lot of diners have latched onto the narrative that the end of Brennan’s is all the about the landlords and the rent hike — but that’s not the whole story. Brennan’s knew the rent increase was on its way for the past 10 years. Wade last negotiated the restaurant’s lease around 2007-08, right before the economic downturn. “Terms that we thought were going to be okay 10 years ago turned out to not be feasible,” she says.

She tried to renegotiate by showing the landlords the restaurant’s financials. “They looked at them and said, ‘Well, you have enough gross sales to pay the rent,’” Wade says. “So they said no, which is a really odd way to look at the restaurant industry. There are people that have to be employed and goods that need to be paid for and liability insurance. To say gross sales are sufficient is really not helpful and not realistic.”

Wade has no plans to open a new restaurant or bar elsewhere — she is getting out of the industry entirely. The business has changed so much from when Wade first learned about it, back in the 1970s when her mom was running Brennan’s. “Drinking has really changed. People used to drink a lot,” she said, adding that ultimately, the change is better for society but not good for restaurants. “In the late ‘70s, a lot of people were snorting a lot of cocaine, so it was this interesting circle of cocaine and you drink a few cocktails to take the edge off, and then you snort more cocaine, and then you have a few more drinks. You had people circling in and out of the bathroom. That stopped.”

The other big shift, Wade says, is climate change. “We’re a comfort food, meat and potatoes place,” she says. “We haven’t had winter. ... Now, when it’s 68 degrees every day in December and February, it’s really hard on us.”

There are no plans for a big farewell celebration. Wade says she is just going to keep serving turkey and corned beef until she runs out of food — hopefully, that doesn’t happen before the scheduled September 15 closing date.

“After 60 years and three generations, it’s really going,” Wade says. “People keep asking how they can save the restaurant. At this point, unless someone wants to buy the restaurant, it’s going.”