Prince Charles has frequently voiced strong opinions about the state of the environment, including the future of farming and the pressure on natural resources.
Prince Charles has been a champion of organic farming
His latest concern is that climate change is the "greatest challenge to face man".
Previously, he has voiced concern about sustainable fish and genetic modification (GM), and has urged Britons to eat more home-grown food so as to support small family farms.
As a long-time champion of organic farming, the prince has been particularly concerned about GM.
In 2002, Charles said people should realise humans, wildlife and the land were inextricably linked.
The prince said the emphasis seemed to be on backing GM crop research "which, regardless of any possible environmental threat, certainly pose an acute threat to organic farmers".
When he received an award for his efforts to protect the environment that year, he also criticised people who dismissed small farms.
"[They are] the ones who most frequently take advantage of the very real benefits that they bring whenever they get away from their offices - the food, the wine, the villages, the atmosphere provided by an ancient sustainable landscape," he said.
He has also said that genetic engineering takes man into the realms that belong to "God and God alone".
"The idea that the different parts of the natural world are connected through an intricate system of checks and balances which we disturb at our peril is all too easily dismissed as no longer relevant."
Prince Charles told the BBC in an exclusive interview broadcast on 25 October that small family farms were "vital" for the preservation of the English countryside and rural communities and that he believed in "food security".
"I think we would be foolish to expect that we can import everything from somewhere else and imagine that this is going to last forever, and ever and ever," he said.
He expressed similar sentiments a year earlier when he promoted mutton at a Mutton Renaissance lunch.
"The main reason behind this whole enterprise is that I actually mind about the family farmer in this country," he told chefs, farmers and meat trade officials at the time.
"If we don't have them then we will have lost something very special in terms of how we look after, manage, and maintain our very precious landscape in this country."
He has also commented on the risk to fish from overfishing and urged the industry to change in order to survive.
People should not stop eating fish, but should only eat species not in decline, the prince said in March 2004.
It was revealed in February 2004 that Prince Charles had intervened to try to prevent the slaughter of millions of cattle during the foot and mouth outbreak three years earlier.
This was despite strict protocol against members of the Royal Family being involved in party politics.
National Farmers' Union chairman Sir Ben Gill told the Times: "Charles was behind the biggest push for vaccination."
During the outbreak the prince made a £500,000 donation to farmers and cancelled a skiing trip to show his support for their plight.