It was the third day of demonstrations this week. On Saturday, thousands had marched through the city for "climate, jobs and justice," and Monday saw about 200 people, mainly indigenous groups, protesting Gov. Jerry Brown's Climate and Forest Task Force.
Thursday morning's demonstration came on day two of the summit, which has drawn more than 4,000 elected officials, business executives and environmentalists from six continents to San Francisco for a three-day conference aimed at addressing carbon emissions and climate change.
Demonstrators outside the conference's main venue at the Moscone Center said they were frustrated that they could not participate in the discussions inside and wanted to make sure their voices were heard.
Protesters crowded the intersection of Howard and Third streets outside the Moscone Center throughout the morning, forcing summit delegates to climb over barriers or go around the gathering.