While members of the royal family don't usually involve themselves in political issues, Prince Charles, reportedly, sent a letter to President Joe Biden to express his full admiration after the new U.S. leader made a very important decision.

On his first day, Biden signed an executive order outlining that the U.S. is re-joining the Paris Climate Agreement, the treaty signed by countries all over the world to work together on environmental issues.

A source revealed that Charles was "hugely encouraged" that Biden's first act is to shift focus on the environment after President Donald Trump withdrew the U.S. from the treaty in 2017. The insider said that both the Prince of Wales and Biden share the same views that the climate crisis is the biggest threat to the lives of every human.

Charles has been staunchly campaigning for governments and major businesses to act on this pressing problem within the next 10 years for the sake of the future generation. With Charles and Biden working together, proponents and advocates of the environment's protection said that they will be a "force to be reckoned with."

On Wednesday, Charles participated in an online discussion about saving the environment. The Prince of Wales once again reiterated that it is the people's duty to care for the planet, which is rapidly being destroyed every day for the sake of progress.

The royal cited a government review that showed a deeper understanding of how economies have a negative effect on the environment. The Prince of Wales said that so much of the earth's resources are lost to economic growth and if this path continues, there will be no more resources for the next generation. He urged for leaders of the world to target protecting 30 percent of the resources in the land and water by 2030 and then move on to the next goal.

In June, Biden is expected to be at the G7 Summit in Cornwall and he will be attending the reception at Buckingham Palace upon the invitation of the Queen. Charles will be at the reception as well, along with Prince William, and they will likely make the environment an important topic of conversation.

But Charles have met Biden before when he and Camilla, the Duchess of Cornwall, visited Washington, D.C., more than five years ago. Charles was at the Oval Office with then-President Barack Obama, while then-Vice President Biden also sat with the two men.