THE WORLD must pay to protect tropical rainforests from further destruction if it is to combat rising greenhouse gas emissions, Britain's most eminent plant scientist warned on Friday.

Urgent financial incentives to stop land being cleared for farming were crucial for tackling global warming and the most cost-effective way of soaking up greenhouse gases, said Stephen Hopper, director of the Royal Botanic Gardens at Kew, in his first interview since taking up the position last month.

Changes in land use and wood burning from deforestation are responsible for 18 per cent of global greenhouse gas emissions each year, more than is produced by the world's transport fleet. Deforestation to make way for crops and pastures was responsible for more than 7 billion tonnes of greenhouse gas emissions in 2000 alone.

Last month, a report by former World Bank chief economist Nicholas Stern said the world must cut back on carbon dioxide emissions by 50 billion tonnes to 70 billion tonnes a year by 2050 to avoid catastrophic climate change. It called for urgent large-scale pilot programmes to explore the best ways to protect natural "carbon sinks," such as the Amazon forest in Brazil and rainforests in Costa Rica and Papua New Guinea.

Professor Hopper said: "The tropical forests are the green lungs of the planet and a first and fundamental strategy is to care for these places. Countries need to give money to poorer nations so they don't have to chop down those forests." New evidence showed that global emissions of the main greenhouse gas carbon dioxide have increased sharply over the past few years.

According to research to be presented at the United Nations climate change summit in Nairobi, carbon dioxide produced by burning fossil fuels leapt by 3.2 per cent from 2000 to 2005. The sharp rise is partly down to the recent growth in the Chinese economy. It compares with an increase of 0.8 per cent in 1990-1999, when several world powers faced recession and the collapse of the Soviet Union closed much heavy industry.

Mike Raupach, chair of the Global Carbon Project, which carried out the new analysis using figures from the United States Department of Energy and BP, said: "This is a very worrying sign. It indicates that recent efforts to reduce emissions have virtually no impact on emissions growth and that effective caps are urgently needed."

Professor Hopper said the global response to the threat of climate change had focussed disproportionately on technological fixes and efforts to trim emissions from industry. "We obviously have to focus on emissions and what we can do to reduce them, but a long term solution that's going to be the lowest cost surely involves caring for plant life that exists out in the big wide world at the moment and repairing and restoring forests that have been damaged in different ways," he said. —

© Guardian Newspapers Limited 2006