The accelerating destruction of the rainforests that form a precious cooling band around the Earth’s equator, is now being recognised as one of the main causes of climate change. Carbon emissions from deforestation far outstrip damage caused by planes and automobiles and factories.

The rampant slashing and burning of tropical forests is second only to the energy sector as a source of greenhouses gases according to report published today by the Oxford-based Global Canopy Programme, an alliance of leading rainforest scientists.

Figures from the GCP, summarising the latest findings from the United Nations, and building on estimates contained in the Stern Report, show deforestation accounts for up to 25 per cent of global emissions of heat-trapping gases, while transport and industry account for 14 per cent each; and aviation makes up only 3 per cent of the total.

“Tropical forests are the elephant in the living room of climate change,” said Andrew Mitchell, the head of the GCP.

Scientists say one days’ deforestation is equivalent to the carbon footprint of eight million people flying to New York. Reducing those catastrophic emissions can be achieved most quickly and most cheaply by halting the destruction in Brazil, Indonesia, the Congo and elsewhere.

No new technology is needed, says the GCP, just the political will and a system of enforcement and incentives that makes the trees worth more to governments and individuals standing than felled. “The focus on technological fixes for the emissions of rich nations while giving no incentive to poorer nations to stop burning the standing forest means we are putting the cart before the horse,” said Mr Mitchell.

Most people think of forests only in terms of the CO2 they absorb. The rainforests of the Amazon, the Congo basin and Indonesia are thought of as the lungs of the planet. But the destruction of those forests will in the next four years alone, in the words of Sir Nicholas Stern, pump more CO2 into the atmosphere than every flight in the history of aviation to at least 2025.

Indonesia became the third-largest emitter of greenhouse gases in the world last week. Following close behind is Brazil. Neither nation has heavy industry on a comparable scale with the EU, India or Russia and yet they comfortably outstrip all other countries, except the United States and China.

What both countries do have in common is tropical forest that is being cut and burned with staggering swiftness. Smoke stacks visible from space climb into the sky above both countries, while satellite images capture similar destruction from the Congo basin, across the Democratic Republic of Congo, the Central African Republic and the Republic of Congo.

According to the latest audited figures from 2003, two billion tons of CO2 enters the atmosphere every year from deforestation. That destruction amounts to 50 million acres – or an area the size of England, Wales and Scotland felled annually.

The remaining standing forest is calculated to contain 1,000 billion tons of carbon, or double what is already in the atmosphere.

As the GCP’s report concludes: “If we lose forests, we lose the fight against climate change.”

Standing forest was not included in the original Kyoto protocols and stands outside the carbon markets that the report from the International Panel on Climate Change (IPCC) pointed to this month as the best hope for halting catastrophic warming.

The landmark Stern Report last year, and the influential McKinsey Report in January agreed that forests offer the “single largest opportunity for cost-effective and immediate reductions of carbon emissions”.

International demand has driven intensive agriculture, logging and ranching that has proved an inexorable force for deforestation; conservation has been no match for commerce. The leading rainforest scientists are now calling for the immediate inclusion of standing forests in internationally regulated carbon markets that could provide cash incentives to halt this disastrous process.

Forestry experts and policy makers have been meeting in Bonn, Germany, this week to try to put deforestation on top of the agenda for the UN climate summit in Bali, Indonesia, this year. Papua New Guinea, among the world’s poorest nations, last year declared it would have no choice but to continue deforestation unless it was given financial incentives to do otherwise.

Richer nations already recognise the value of uncultivated land. The EU offers €200 (£135) per hectare subsidies for “environmental services” to its farmers to leave their land unused.

And yet there is no agreement on placing a value on the vastly more valuable land in developing countries. More than 50 per cent of the life on Earth is in tropical forests, which cover less than 7 per cent of the planet’s surface.

They generate the bulk of rainfall worldwide and act as a thermostat for the Earth. Forests are also home to 1.6 billion of the world’s poorest people who rely on them for subsistence. However, forest experts say governments continue to pursue science fiction solutions to the coming climate catastrophe, preferring bio-fuel subsidies, carbon capture schemes and next-generation power stations.

Putting a price on the carbon these vital forests contain is the only way to slow their destruction. Hylton Philipson, a trustee of Rainforest Concern, explained: “In a world where we are witnessing a mounting clash between food security, energy security and environmental security – while there’s money to be made from food and energy and no income to be derived from the standing forest, it’s obvious that the forest will take the hit.”