Two environmentalists spent about four hours Monday perched on a ledge over an entrance to a National Oceanic and Atmospheric Administration building to protest what they said is the agency's suppression of information on global warming.

The pair, which climbed a ladder to reach the ledge, unfurled a banner that read "Bush: Let NOAA Tell the Truth," while a small group of demonstrators handed out fliers on a nearby sidewalk.

Police eventually used a cherry picker from a nearby construction site to reach the demonstrators and lower them to the ground. Both men, Ted Glick, 56, and Paul Burman, 23, were charged with disorderly conduct, reckless endangerment and trespassing.

The men had climbed to the ledge using a ladder and used suction cups to anchor themselves to a window.

NOAA, based in Silver Spring, studies climate, weather and the oceans. Its agencies include the National Weather Service and the National Marine Fisheries Service.

The demonstrators said they were part of the U.S. Climate Emergency Council and the Chesapeake Climate Action Network. The groups claim NOAA denies scientific evidence that recent severe weather, such as powerful hurricanes, is caused by climate change. They also allege NOAA withholds proof of this effect.

"People are seeing that the climate is changing," said Mike Tidwell, head of the Chesapeake Climate Action Network. "A grass roots movement is emerging from that."

In a statement Monday, NOAA spokesman Jordan St. John said: "We're proud of our scientists and the great work they do, and we encourage vigorous peer review and public discussion."

A report in the scientific journal Nature last month claimed NOAA administrators blocked the release of a report that linked hurricane strength and frequency to global warming. In February, a NASA climate scientist said NOAA prevents researchers working on climate change from speaking freely about their work.

NOAA denied both allegations and says its work is not politically motivated.