A total of 82 people were arrested during a so-called "rebellion day" which saw five major London bridges blocked by activists, police have said.
Thousands of demonstrators occupied the bridges for most of Saturday as part of demands for the government to take greater action on climate change.
It followed a week of action by campaign group Extinction Rebellion.
The Met said most arrests were for breaches of the Highway Act and all 82 had been released under investigation.
Large groups of people holding banners began congregating on Southwark, Blackfriars, Waterloo, Westminster and Lambeth bridges from 10:00 GMT before blocking off the traffic.
Many then moved to a rally in Parliament Square where speeches were held and three trees were planted.
Tiana Jacout, of Extinction Rebellion, said the blockages were "not a step we take lightly" but "if things continue as is, we face an extinction greater than the one that killed the dinosaurs".
According to the organisers, 6,000 people had taken part.
The Met said the protests had caused "significant traffic disruption" and "hampered" emergency service vehicles from getting across London.
The force previously reported that 85 people had been arrested but the number was revised down due to duplicating reports made by officers.