As world leaders gather for the Cop26 conference in Glasgow for the global environmental summit, Pope Francis has urged them to take radical decisions.

In his message, he said: “Climate change and the Covid-19 pandemic have exposed our deep vulnerability and raised numerous doubts and concerns about our economic systems and the way we organise our societies.

“We have lost our sense of security, and are experiencing a sense of powerlessness and loss of control over our lives. We find ourselves increasingly frail and even fearful.” His message was recorded in Italian and lasted almost five minutes.

The Pontiff, who will not be able to attend the conference, went on to say: “We can confront these crises by retreating into isolationism, protectionism and exploitation. Or we can see in them a real chance for change, a genuine moment of conversion, and not simply in a spiritual sense.”

He is not attending the summit, despite earlier suggestions that he would fly in for a brief appearance to reinforce the significance of the event. In 2015, Francis published an encyclical on the environment that was a call to the world population to take urgent action to avert a climate catastrophe.

Another person who will not be in Glasgow is The Queen will not attend following medical advice to rest. The 95-year-old underwent preliminary medical checks in hospital after cancelling a visit to Northern Ireland.

Buckingham Palace said that she regrets not attending a reception at the summit. But the palace said she would deliver her address to delegates using a recorded video message instead.