Shoppers and visitors to the street were greeted with members of the climate change campaign group on the floor – with placards and protest signs placed on those on the ground on the street.
Activists lay on the ground covered in white sheets with placards laid out on the “bodies” with the “causes of death” including heat stress, famine and water scarcity.
Scotland recorded its hottest day in history on Tuesday, with 35.1C being recorded at Floors Castle in the Borders.
Damien McGovern, a 41-year-old NHS physiotherapist, said he took part in the “die-in” to urge for immediate action.
He said: “If your house was on fire, you wouldn’t sit around and have a chat about it for 30 years or choose to throw more fuel on it to burn even faster.
“So why are we allowing this to happen to our planet?”
Some parts of Scotland have also been issued with weather shortage warnings following the heatwave.
The Scottish Environment Protection Agency (Sepa) said on Friday that “water scarcity is a very real threat as a result of climate change”.