Activists on Monday chanted slogans and held signs that read “There is no Planet B” and “Extinction is Forever” at Marble Arch, Oxford Circus and Waterloo Bridge.
Demonstrators said protests could last at least a week. Police said roadblocks were due to continue night and day at each site.
The protests were organized by the British environmental group Extinction Rebellion and are to involve demonstrations in 33 countries around the world over the coming days.
Extinction Rebellion has warned its members that some of them could be arrested for taking part in non-violent civil disobedience.
The group is demanding the government declare a climate and ecological emergency, reduce greenhouse gas emissions to net zero by 2025 and create a citizen’s assembly of members of the public to lead on decisions to address climate change.
The group also wrote to UK Prime Minister Theresa May on Monday outlining their demands and asking for face-to-face talks, warning that they will escalate their disruptive actions over the coming weeks unless the government acts.
“Make no mistake, people are already dying,” the letter states. “In the majority world, indigenous communities are now on the brink of extinction. This crisis is only going to get worse … Prime minister, you cannot ignore this crisis any longer. We must act now.”
Activists said they smashed the glass of a revolving door at the Royal Dutch building near the River Thames and caused more than 6,000 pounds worth of damage.
Police said 113 people have been arrested so far. “There have been 113 arrests in total, the majority of which are for breach of Section 14 Notice of the Public Order Act 1986 and obstruction of the highway,” London police said.
The disruption follows similar action last November when thousands of protesters occupied five central London bridges. Police arrested 85 people that day.
Rowan McLaughlin, 47, a teacher, said this week’s protests were more important than the huge pro and anti-Brexit protests in London recently.