King Charles told the German president that he was becoming a "frustrated old man" over climate change during his recent visit.
He made the remarks on the final day of his visit as he took in the sights of Hamburg.
According to express.co.uk, the monarch praised the younger generation for their impetus in fighting climate change.
Speaking on the occasion, he stressed the need for the world to move faster towards sustainability.
The publication reported that Charles was taking in the sights of Hamburg's impressive harbour by boat with German President Frank-Walter Steinmeier, where they viewed a state-of-the-art electrolyser site which helps generate power.
"I’m becoming a frustrated old man. It all seems obvious to me. The younger generation know, certainly," Charles told the president.
His remarks were widely shared on social media, with royal fans expressing concern whether Charles is too old to become a monarch. They think king's remarks could be used against him by critics in the future.
It said the Mayor of Hamburg Peter Tschentsche explained how a retired coal yard was now housing the revolutionary electrolyser and helping the city in its commitment to achieving net zero emissions by 2050.
"The benefit is, new technologies are developing at a rate….and new opportunities are being realised all the time," the publication quoted the mayor as saying.
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