Climate change protest, Copenhagen 2009. Protestor arguing with police during protests at the 2009 United Nations Climate Change Conference in Copenhagen, Denmark, held from 7-18 December 2009. The conference, which failed to reach agreement on intergovernmental actions to tackle climate change, was marked by large-scale demonstrations. Up to 100,000 people were thought to have taken part in the protests, with hundreds detained by the police, though most were released without charge.