The stunt, organised by pressure group Extinction Rebellion (XR), sees individuals sitting alone in busy roads wearing signs with messages about their fears for the future.
The protest began at 11am on May 1 – two years exactly since Parliament declared a climate emergency.
Bing Jones, a 68-year-old retired NHS doctor from Nether Green, blocked Ecclesall Road in Sheffield for 40 minutes. His sign read: “I am terrified by empty promises on the climate crisis”.
The grandfather said: “We have targets for 2050 but we are still increasing emissions today. The Government has made inexcusable Covid mistakes. I’m terrified that they will be even worse on the climate crisis.”
He added: “I am desperate. I write, lobby and support green politics but see nothing real happening.
“So I am sitting in the road today with a notice saying I am terrified. I am sorry to disrupt ordinary people but I do not know what else to do.”
Other protesters included civil engineer Morgan Trowland, who glued himself to London’s Tower Bridge, another man who blocked Blackfriars Bridge in the capital, and nurse Andrea Muntiu, 36, who blocked traffic in her home town of Ipswich.
She said: “I am aware of the risks but I feel I have a moral duty to warn people about the catastrophic consequences of the climate crisis.”
Extinction Rebellion activists also took part in a Kill the Bill protest in Sheffield city centre.
The Police, Crime, Sentencing and Courts Bill was drafted partly in response to previous disruptive action by XR and also the Black Lives Matter movement.
The proposed legislation would give police in England and Wales more powers to impose conditions on non-violent protests.
A Home Office spokesman said: “The right to protest is a cornerstone of our democracy, but over recent years we have seen an increase in the use of disruptive and dangerous tactics.”
He added: “These new measures will not stop people from carrying out their civic right to protest and be heard, but will prevent large scale disruption – enabling the silent majority to get on with their lives.”