The action marks the 12th day in the past four weeks that the group has carried out road protests.
Insulate Britain protesters have blocked a major road in central London and a junction on the M25, causing long queues of rush hour traffic.
The group said about 40 activists had blocked the roundabout at Old Street and junction 25 of the motorway at Waltham Cross in Hertfordshire.
The Met Police said four people who were glued to the road on the M25 had been arrested and were being removed.
Transport Secretary Grant Shapps branded activists “glued fools”.
He told LBC: “It’s dangerous, it’s really outrageous, and actually, ironically, it probably adds to pollution as cars idle, waiting… for them to be unglued from the road.”
Mr Shapps added that he had applied for more than 100 court injunctions covering the national highway network around London and the South East, which could lead to jail terms.
The action marks the 12th day in the past four weeks that Insulate Britain has carried out road protests.
The activists want the government to commit to providing insulation for 29 million homes.
On Tuesday, drivers clashed with protesters at the entrance to the Blackwall Tunnel where 38 people were arrested.
Insulate Britain admitted that its latest action on the M25 was “in breach” of an injunction obtained by the government last month.
However Tracey Mallagan, a spokeswoman for the group, said: “If governments don’t act soon to reduce emissions, we face a terrifying situation.
“We won’t be worrying about shortages of pasta or loo rolls because law and order breaks down pretty quickly when there is not enough food to go round.”
The government has said it is investing £1.3bn to support people to install energy efficiency measures.