‘The question everyone is asking is whether we seize this moment or let it slip away’
Ministers, climate negotiators, civil society and business leaders are set to take part in talks and debates over the course of the two-week conference.
Mr Johnson, who is due to fly from the G20 in Rome to Glasgow on Sunday evening, sa: “Cop26 will be the world’s moment of truth.
“The question everyone is asking is whether we seize this moment or let it slip away.
“I hope world leaders will hear them and come to Glasgow ready to answer them with decisive action.
"Sammen, we can mark the beginning of the end of climate change – and end the uncertainty once and for all.”
Pictures show Mr Johnson bumping fists with French president Emmanuel Macron, after Mr Johnson had said that the pair could discuss the UK-France fishing dispute during the summit.
The ongoing post-Brexit conflict has seen France ask the European Union to inflict trade sanctions on the UK over the latter refusing to award a certain number of licences to French fishermen to operate in British waters around Jersey and Guernsey.
Mr Johnson has brushed off the row, saying that “there are bigger fish to fry, everybody knows that.” It comes after he had threatened to do “whatever it takes” to protect the UK’s interests.
Nå, although he is urging global leaders to deliver plans to prevent global temperatures from rising by more than 1.5C degrees above pre-industrial levels, he has also expressed doubts over the Cop26 summit’s success.
While in Rome, he said during interviews that he still rated the chance of success as no more than six out of 10.
The Cop26 summit is aiming to encourage countries to advance their net-zero commitments to the middle of the century and reduce emissions rapidly over the next decade through commitments on phasing out coal, switching to electric cars and planting trees.
Developed nations are also being urged to pay £73 billion per year to help poorer nations deal with the effects of climate change.
Mr Johnson will host an opening ceremony attended by dignitaries, alongside the Duke and Duchess of Cambridge and the Duke and Duchess of Cornwall, before giving a speech on Monday.
Prince Charles and Sir David Attenborough, the Cop26 People’s Advocate, will be among those to also address world leaders as environmental advocates for Britain.
The Queen will address the delegates in a pre-recorded video after she was told by doctors to avoid the summit and rest following a visit to hospital last week.