Associated Press
Alain Robert climbs the New York Times building with his bare hands to bring attention to global warming Thursday in New York.

NEW YORK — A Manhattan skyscraper that is home to the New York Times became the site of twin daredevil stunts Thursday, with two men scaling the 52-story office tower within a matter of hours.

The first man, Alain Robert, unfurled a banner as he climbed that said "Global warming kills more people than a 9/11 every week." He was arrested when he made it to the top.

Hours later, a second man ascended the building — a stunt that drew the attention of thousands of onlookers, along with TV cameras that captured the drama in real time. Crowds on the street pressed against police barricades to watch, and people clapped and cheered for the climber while snapping pictures on their cell phones.

The man, identified later by police as 32-year-old Renaldo Clarke of Brooklyn, was also taken into custody as he reached the top.

"Only in New York. This is why I live in New York," said 29-year-old Emily Perschetz, who watched the second climber for about 20 minutes.

"You've got to respect them for trying," she added.

At moments during his ascent, Clarke appeared to slow and tire, and officers awaiting him shouted encouragements from the rooftop and even dangled a rope, which he did not take, police said.

Officers became concerned that Clarke might be an emotionally disturbed copycat, and he was taken to a hospital for a psychiatric evaluation, according to police. There was no working phone number listed under Clarke's name and address.

The facade of the newly constructed building, which the Times moved into only last year, is covered with slats that allowed the men to climb the tower like a ladder.

Robert pumped his fist as he made it to the top, where police took him into custody. The 45-year-old was facing charges of reckless endangerment, criminal trespass and disorderly conduct, police said.

Robert's Web site says he has climbed more than 70 skyscrapers around the world. He was arrested in February after climbing a 42-floor building in Sao Paolo, Brazil.

A spokeswoman for the Times, Catherine Mathis said the newspaper was "taking steps to prevent future occurrences."

"Their illegal and ill-considered actions jeopardized their safety and the safety of others," Mathis said in a statement.

She earlier said no one at the newspaper knew of Robert's plan in advance.

Reacting to the content of Robert's banner, Mathis noted that the Times itself has "a very green building."

"We wanted to minimize our environmental footprint," she said, adding that the ceramic slats save energy by reducing the amount of heat and light entering the building.

Robert said in a news release that he was climbing to mark World Environment Day and "to create support for far greater and urgent action from world leaders on global warming."

His Web site says he climbs even though he suffers from vertigo and is "60 percent disabled" from previous accidents. It also says that he has been jailed many times but that it does not matter, because he "would rather stay in a prison than in a hospital."

Clarke wore a T-shirt with the words "Malaria No More," the name of an organization that promotes awareness about malaria and raises money for bed nets. Martin Edlund, a spokesman for the organization, said Clarke was not affiliated with the group.

Clarke's Facebook page says he enjoys climbing and lists "xtreme living" among his interests. The page identifies him as an information technology support manager for a Manhattan advertising agency, and it says he is pursuing an undergraduate degree in physics. He did not immediately return an online message.

One city councilman is hoping that at least one of the climbers gets to know what the inside of a New York City jail looks like.

"Regardless of the cause, in this day and age the police department has more important things to worry about then ridiculous stunts like this that endanger the police and public," Councilman Peter Vallone Jr. said after Robert's climb. "If he wants to climb something, he can climb the walls inside his jail cell at Rikers."

Shaznay Jones was more amused than Vallone as she watched the second climb while smoking a cigarette.

"It looks crazy, like he's on drugs, like he's on something," Jones said. "I never saw anything like this before."

New York's skyscrapers have long attracted high-rise stunts.

The host of a cable TV show called "Stunt Junkies" was arrested in 2006 as he tried to parachute from an Empire State Building observation deck. Police and security guards seized him and handcuffed him to the 86th-floor security fence as he climbed over it.

And in 1974, French artist Philippe Petit made a daring and illegal wire-walk between the twin towers of the World Trade Center. British director James Marsh made "Man on Wire," a retelling of the derring-do.