They did NOT toss coins for “good luck fighting the climate emergency.” Maybe some did, who knows. It was not a collective wish for something, just a stage for a nice group photo.

https://www.yahoo.com/video/made-wish-g20-leaders-toss-113600490.html?guccounter=1

https://www.bloomberg.com/news/articles/2021-10-31/g-20-leaders-pose-by-trevi-fountain-macron-and-johnson-face-off

From the Yahoo article: “Of course the wishes can’t be revealed to anyone if they are to become true - so who knows what British Prime Minister Boris Johnson, French President Emmanuel Macron, outgoing German Chancellor Angela Merkel wished for.”