The Prince said it is the "duty of wealthy nations" to take action

He told a WWF dinner at Hampton Court Palace that it was crucial to find ways to make it more profitable to save rainforests than cut them down.

Prince Charles said the destruction was happening at a "truly terrifying pace".

He announced the Prince's Rainforests Project to find solutions that can be put in place within 18 months.

Life-support system

Prince Charles said: "Every year 50 million acres - an area the size of England, Wales and Scotland combined - are destroyed or degraded."

He told the audience that the consequent burning of the forests accounted for as much as 20% of global greenhouse gases, a level of output only surpassed by the energy sector.

He said the forests stored carbon, provided the atmosphere with moisture and supported the lives of 1.4bn of the world's poorest people.

"The simple fact is that combating deforestation is likely to be one of the quickest and cost-effective means of reducing carbon dioxide emissions," he added.

We simply have to find ways of putting a price on them which makes them more valuable alive than dead The Prince of Wales

The prince warned that strategies currently in place to control CO2, such as the Kyoto and European Emissions carbon trading schemes, do not give credits for rainforest conservation.

He said: "It seems to me that the central issue in this whole debate is how we put a true value on standing rainforests to the world community.

"We simply have to find ways of putting a price on them which makes them more valuable alive than dead."

He said the Prince's Rainforests Project would work with the private sector, governments and environmental experts to find credible action that can be taken within 18 months.