The 'high level of police officer deployment' required means officers will be unable to attend trials as witnesses.
A Glasgow City Council committee heard the climate summit would go ahead in person or be delayed.
Alok Sharma to make speech ahead of November 1-12 meeting that will bring world leaders together to tackle the issue.
Media reports on Wednesday suggested that the Glasgow summit this year may be pushed back or scaled down.
Senior police chief says arrival of US President Joe Biden and Pope Francis would 'escalate the event significantly'.
Labour frontbencher makes call as Glasgow prepares to host UN Climate Change Conference in November.
Boris Johnson accused of 'personal animosity' towards Nicola Sturgeon as he hints at blocking FM's attendance.