How many protesters?

Thousands protest at climate summit - thestar.com

Police estimated their numbers at 25,000, while organizers said as many as 100,000 had joined the march from downtown Copenhagen, waving banners that read "Nature doesn't compromise" and ``Climate Justice Now.''

Hundreds of Protesters Arrested at Climate Talks - NYTimes.com

The police and organizers estimated that 60,000 to 100,000 participants joined a long march from Christiansborg Slotsplads, or Castle Square, southward to the Bella Center
...
People calling for a free Tibet were well represented, and a small contingent of climate skeptics and libertarians derided the United Nations talks.

“We want to be able to live our lives like we’ve always led them before — as free citizens in free democracies,” said David Pontoppidan, a graduate student in sociology at the University of Copenhagen, who addressed passers-by through a megaphone over the chatter of two helicopters hovering far above. “We want free debate; we want to be able to be taken seriously even though we don’t agree with the U.N.”
...
Andrew C. Revkin and Lars Kroldrup contributed reporting.