By David W. Dunlap

New York Times

UNITED NATIONS >> In New York, “temporary” train stations, “temporary” art installations and “temporary” sidewalk sheds can endure for a decade or more. So it is a marvel to report that an interim building will turn out to be just that.

Perhaps because it is technically not in New York.

The 6-year-old, $140 million North Lawn Building, an almost windowless mass of concrete and white corrugated steel that stretches from 46th Street to 47th Street along the East River, was designed to house the critical operations of the United Nations while the headquarters complex was being renovated.

Now that the $2.15 billion renovation is finished, the North Lawn Building is, too.

It is to be demolished over the next five months, though “dismantled” might be a better word, since the contractor has an incentive to recycle.

The United Nations set an upper limit of $16.76 million for the demolition contract, which was competitively bid. That encouraged prospective contractors to extract as much value as possible from the reuse of building materials.

This approach attracted contractors who could not only recycle air-conditioning units and steel panels but who had the “sophistication to grind up concrete and sell it to highway departments,” said Michael Adlerstein, the assistant secretary general who oversaw the renovation. The winning bidder was Gramercy Group.

Another marvel to report: The building will be replaced by open space.

The North Lawn — the lungs of the headquarters complex — is to be recreated. Part of the Berlin Wall given in 2002 by Germany will return to the lawn from the sidelines, as will artworks like Antun Augustincic’s equestrian “Peace” sculpture, given by Yugoslavia in 1954.

Planting will begin in spring. Final landscaping should be completed in time for the 2016 General Debate, said Werner Schmidt, a public information officer.

The General Debate is the autumnal meeting of world leaders, at the beginning of the General Assembly, that generally slows the Turtle Bay section of Manhattan to a crawl. It is held in the domed General Assembly Hall, which opened in 1952.

The hall ennobles even the most contentious speakers with its majestic rostrum. A green marble lectern bearing the U.N. emblem sits before a green marble dais. Above hovers a lustrous, curving 75-foot wall of gold leaf with a colossal version of the U.N. emblem — a polar azimuthal equidistant projection of the globe embraced by olive branches — in shimmering aluminum leaf.

In 2013, the General Debate was moved to the North Lawn Building, about 150 feet away, which was designed by the architecture firm HLW.

The temporary assembly hall had a lectern and dais made of faux-marble composite board. The wall was painted gold and stood only 18 feet high.

President Barack Obama stood at the composite-board lectern on the morning of Sept. 24, 2013, to tell the community of nations that the United States would be engaged in the Middle East “for the long haul.” President Hassan Rouhani of Iran followed him in the afternoon, saying that the United States and Iran could “arrive at a framework to manage our differences” on a nuclear agreement. The leaders avoided meeting each other, however.

A few days later, Prime Minister Benjamin Netanyahu of Israel said Iran’s nuclear weapons capacity must be fully dismantled. “To say Iran doesn’t practice terrorism is like saying Derek Jeter didn’t play shortstop for the New York Yankees,” he said.

In the tight shots favored by most photographers and camera operators, the stage-set rostrum passed muster, Adlerstein, the assistant secretary general, said.

Besides, he said, “The business of the United Nations is so intense in rooms like the General Assembly or Security Council that all you need is to give a sense of the place.”

That may be, but Secretary-General Ban Ki-moon told delegates in 2013: “I will make sure that by next year this time, leaders will be able to take the floor in the newly renovated General Assembly Hall. I hope you will convey this message.”

In the measured language of diplomacy, the message was really directed to Adlerstein as much as anyone. It amounted to an order. He took it as such.

Though the capital master plan office was otherwise given a good deal of autonomy in the renovation, it hurried to finish the sumptuous restoration of the real assembly hall in time for the 2014 General Debate.

Since then, the temporary hall has seen several uses, most recently as a workroom for Umoja, a project under which the United Nations is consolidating many different computerized management systems.

The global emblems from the temporary rostrum were salvaged for future use, Schmidt said. All else was turned over to the demolition contractor.

But the North Lawn Building has at least a tiny place in history. To celebrate the rejuvenation of the headquarters complex, Rizzoli published “The United Nations at 70: Restoration and Renewal.” Schmidt took the cover photograph.

Try as he might, he could not quite crop the building out.

© 2016 The New York Times Company