One of the world's most prominent conservation experts yesterday issued a rallying cry to save the great apes, man's closest biological cousins, which are under serious threat of extinction. Richard Leakey, former head of the Kenya wildlife service and now chair of Wildlife Direct, said apes across the world faced unprecedented threats from the combined effects of hunting, disease and logging. And he said efforts to tackle global warming through the use of biofuels could cause more damage to ape populations because of pressure to chop down their tropical forest homes.

About 80% of orang-utan habitat in south-east Asia has been destroyed in the past 20 years because of soaring demand for land to produce palm oil for western markets. Experts warn that increased uptake of alternative fuels could mean the disappearance of the remaining 50,000 animals there within a generation.

Dr Leakey, who will outline his concerns in a public lecture tonight at the Royal Geographical Society in London, said human activity was directly to blame for the deaths of millions of gorillas, chimpanzees and bonobos across the world. He urged politicians working on a new international treaty to regulate greenhouse gas emissions to focus more on incentives to conserve forests across south-east Asia, Africa and central and south America.

Dr Leakey said: "People shrug their shoulders and say what are poor countries to do if they can't export their natural resources, and I understand this, but it is simply not sustainable the way it is going. The threat to great ape populations around the world is growing visibly." He said preventing deforestation would help curb global warming as well as preserving endangered apes. Carbon released by deforestation is reckoned to account for 25% of all human greenhouse gas emissions, second only to the energy generation sector.

Scientists say conserving forests offers one of the cheapest ways to tackle climate change, and steps to reward tropical countries which leave their forests untouched will be discussed at the G8 summit in Germany next week. Dr Leakey, a patron of a United Nations Environment Programme great apes survival project, called for more "imaginative" solutions such as credits for preserving biodiversity and wildlife habitats which a country could sell to others to offset their carbon pollution. "We find it very hard to preserve natural beauty, but we are happy to spend £80m on a Picasso and a fortune looking after it."

But he insisted developing countries must take their share of responsibility for global warming. "Developing countries are shrill about the damage that developed countries have caused with their pollution," he said. "The developing world should have a comparable amount of responsibility because of deforestation. I don't think we [Kenya] can afford to shelter behind the fact that we're a new country and we were grossly exploited before, and so we need to be given a break. We need to look at the effect we're having on the whole planet."

He called for a "huge revolution in entrepreneurial skills" to develop technology such as nuclear fusion and hydrogen power as a way of limiting the need for biofuels. "The whole biofuel issue is of great concern. And it's not just biofuels, the destruction of rainforest to make way for palm oil plantations is extraordinary." A UN report this month also raised concerns over a rapid expansion of biofuels, saying they could have an irreversible environmental impact. There are also concerns about their impact on global food prices, with growing competition for scarce land resources.

Dr Leakey said the direct effects of climate change could spell disaster for the great apes. "I don't think we can say enough to stimulate concern over climate change. It's a complex process but it will undoubtedly impact on everything we know and the implications for biodiversity are there for all to see. We don't know the tolerance of plants to the predicted temperature changes. We should not for a minute assume that forests, rivers and lakes are permanent features of our landscape."

He also criticised what he called the "oxymoron" of ecotourism, which he said was based on "a desperate race to make money while you still can". He said: "An awful lot of damage is done under the umbrella of ecotourism. The tourism industry needs to be talked to very seriously about setting standards that are something other than profit-motivated."

Profile: Richard Leakey

Born in Kenya in 1944 to two esteemed anthropologists, Richard Leakey led expeditions which uncovered a steady stream of human-ancestor fossils during the 1970s which dazzled the scientific world and helped to clarify our evolutionary history. Among the most important finds are the remains of Turkana Boy, a 1.6m-year-old Homo erectus skeleton, recovered virtually intact, as well as the 2.5m-year-old Black Skull, which forced palaeontologists to drastically rethink the structure of the human family tree.

In 1969 he was diagnosed with a terminal kidney disease and a decade later received a lifesaving transplant from his younger brother. In the 1980s he devoted more of his time to Kenya's museums and, subsequently, conservation issues. From 1989 to 1994, as head of the Kenya wildlife service, he beefed up the country's national parks and led high-profile and successful campaigns against elephant poaching. In 1993 he lost both legs below the knee when the plane he was piloting malfunctioned and crashed. Rumours of sabotage were never proven. In the mid-1990s he entered Kenyan politics, first as co-founder of a new opposition party, and then in government at the invitation of former president Daniel arap Moi.

(Por David Adam, The Guardian, 31/05/2007)