In theory, New York City Mayor Michael Bloomberg’s landmark plan to reduce greenhouse gas emissions by retrofitting leaky old buildings was a good idea. In the face of a global recession, and with a mandate for building owners to foot much of the bill, the owners didn’t agree.

Now, after fierce criticism, the city is dropping a plan that would have required older buildings — those measuring 50,000 square feet or more —to perform energy audits and subsequent efficiency upgrades, according to the NY Times.

If passed, the mandate would have applied to roughly 22,000 buildings, or nearly half the city’s square footage, requiring owners to upgrade light bulbs, old boilers and leaky windows. The legislation also would have represented a big push in the green building movement, since most cities impose efficiency standards on new construction only. In the city, buildings contribute 80 percent of the city’s total carbon emissions, and Mayor Bloomberg is trying to lower emissions by 30 percent by 2030.

A major sticking point was cost, with owners required to pay for most of the upgrades. Officials estimated private investors would need to kick in $2.5 billion for building improvements since the city only had $16 million in federal stimulus funds to pay for such changes.

“It’s another unfunded mandate, and this is just not the time for it,” Stuart Saft, chairman of the Council of New York Cooperatives and Condominiums, told the Times. “Come back in five years when we’re past this recession. At this point it’s just a slap in the face.”

Saft added that buildings owners were opposed to mandatory audits, as well. “In this climate? Zero chance,” he said. “No one wants to raise the operating costs of the building.”

Unveiled on Earth Day earlier this year, the plan drew praise from environmentalists after Mayor Bloomberg called it part of “the world’s most comprehensive package” to reduce greenhouse gas emissions from buildings. The mayor projected 19,000 new construction jobs related to the renovations, specifically lighting changes and energy inspections.

Now, those prospects are considerably dimmer.

“I’d be shocked if 5,000 of those jobs were created,” said Louis J. Coletti, head of the Building Trades Employers’ Association. “The world of real estate and construction financing have been upended by the economic crisis.”

Still, city officials are not giving up. They are moving forward with new legislation to require energy audits, though the bill will leave it up to building owners to decide which upgrades to implement.

City officials say the new cohort of bills will still have an impact. Specifically, the legislation will create the city’s first energy code for all buildings, and large commercial buildings will provide tenants with information about their individual energy usage.

City Council Speaker Christine Quinn praised the smaller changes: “Getting to a decent first-round reduction, that’s key for me.” Added Ashok Gupta, director of energy policy at the Natural Resources Defense Council: “Even though the bill is not as strong, it’s still ahead of the rest of the country.”