Eleven Greenpeace members were arrested Wednesday for mounting a protest on the granite presidential faces of Mount Rushmore National Memorial to urge President Obama to "show real leadership on global warming."

Park staff were alerted by security systems at 10:11 a.m., local time that a number of individuals had breached a controlled area and accessed the top of the monument. While the climbers were able to unfurl a 65-foot-by-35-foot banner next to Abraham Lincoln's face, they were arrested shortly thereafter and taken to Rapid City, South Dakota, and jailed. Possible charges range from trespass to destruction of government property.

Park workers planned to assess the monument for any damage and were to remove the banner as soon as they could safely do so.

National Park Service officials would not say how the 11 managed to evade Mount Rushmore's security systems, reach the top of the monument, and rappel down its face, nor would they describe what security measures are employed at Mount Rushmore.

The banner draped across the front of the monument featured an unfinished portrait of President Obama with the message, "America honors leaders not politicians: Stop Global Warming."

The demonstration comes as President Obama met with other G8 leaders in L'Aquila, Italy, on Wednesday to discuss the global warming crisis in the lead-up to UN climate treaty negotiations in Copenhagen this December.

"This monument celebrates leaders who rose to the great challenges of our past. Global warming is the greatest crisis humankind has ever faced and it is the defining test of leadership for this generation. It's an open question whether President Obama will pass that test," said Greenpeace USA Deputy Campaigns Director Carroll Muffett.

According to a Greenpeace release the activists were trained in rock and industrial climbing and took special care not to damage the monument, using existing anchors placed by the National Park Service for periodic cleanings.

The demonstration followed a series of protests in Italy earlier Wednesday where other Greenpeace activists hung banners on coal plant smokestacks calling attention to the collective failure of leadership on global warming at the G8.

"We're at a moment in history where President Obama must show real leadership on global warming, not only for Congress and the American people, but for the world. Unfortunately, the steps taken to address the crisis so far have been grossly inadequate," said Muffett. "While President Obama's speeches on global warming have been inspiring, we've seen a growing gap between the president's words and his actions."

According to Greenpeace, "the best science shows that to avoid catastrophic global warming, governments must take action to keep global temperature rise as far below 2 degrees Celsius as possible.

"Given President Obama's pledge to follow the science, it's troubling that his administration has not yet endorsed emission targets strong enough to keep us below that critical threshold," the activist group said.

Furthermore, the group, said, the experience earlier this year "with climate legislation in the U.S. House of Representatives, which was drastically weakened by lobbyists for the oil and coal industries and other big polluters, showed that unless the president provides strong leadership on this issue, special interests will win out over the common interest."

"Doing what it takes to solve global warming demands real political courage," Muffett added. "If President Obama intends to earn a place among this country's true leaders, he needs to show that courage, and base his actions on the scientific reality rather than political convenience."

Greenpeace is calling on President Obama to use every tool at his disposal, both within and outside Congress, to strengthen U.S. climate policy with scientific integrity, and to take that policy to Copenhagen in December as evidence the U.S. will do what it takes to solve the climate crisis.

Specifically, Greenpeace is calling on President Obama to:

* Strive to keep global temperatures as far below a 2 degrees Celsius increase as possible, compared to pre-industrial levels to avert catastrophic climate change;

* Set a goal of peaking global emissions by 2015 and be as close to zero as possible by 2050, compared to 1990 levels;

* Cut emissions in the U.S. by 25-40 percent by 2020, compared to 1990 levels;

* Join and encourage other members of the G8 to establish a funding mechanism that provides $106 billion per year by 2020 to help developing countries adapt to global warming impacts that are now unavoidable and halt tropical deforestation.

Greenpeace is also calling on President Obama to attend the Copenhagen conference personally to ensure a strong, science-based agreement is reached.