Oxford zoologist Andrew Mitchell said the Forests Now declaration by the Global Canopy Programme - a group of 38 scientific institutions in 19 countries have called for implementation of a carbon market policy.
Under this, states and organizations that generate the most carbon dioxide will pay governments to preserve their tropical forests instead of cutting them down for timber, to grow crops or to support livestock.
"This is a declaration of hope. Halting deforestation is an opportunity to score a big win against climate change. These forests support 1.4billion of the world's poorest people and offer services critical to humanity's survival, such as rainfall generation. These are benefits we all need but do not yet pay for," said Mitchell.
He said the forests contained 60 per cent of the world's stored carbon and although they covered less than seven per cent of the world's surface area they provided a home for half of all known species.
"Deforestation in the tropics and sub-tropics causes up to 25 per cent of carbon emissions, second only to that of fossil fuels," the Daily Mail quoted Dr Mitchell as saying.
Climate campaigner Kevin Conrad said: "Global markets for cows and coffee have been driving-deforestation. The measures called for in the declaration-offer an opportunity to compete head to head with the money a country can make elsewhere while protecting forests".
The declaration states that governments should ensure that the need to maintain forests is written into to all international carbon-trading agreements and that carbon-market rules should encourage the planting and development of more forests.
It adds: "Deforestation and forest degradation are driven by external demands for timber, beef, soya and biofuels which destroy trees for land, raising the stakes of global warming".
"Yet tropical forests continue to be excluded from carbon markets that could provide the alternative strategies needed".