Bricks and mortar are so passé. So forget Dorset and join the Patagonian land grab, taking your lead from CNN supremo Ted Turner (owner of 128,000 acres) or the well-healed Chilean Sebastián Piñera, who has created the Parque Tantauco (120,000 hectares) ostensibly to conserve Patagonia's virgin forests, which are obviously vital carbon sinks. No matter that Piñera earned his fortune as the operator of Chile's biggest airline (I know, the CO2 irony!) - that's no barrier to becoming a Wildlife Philanthropist (WP), stocking up on land to preserve biodiversity for future generations.

If Patagonia is out of your reach, how about a more modest WP act? £50 to the World Land Trust (worldlandtrust.org) will buy an acre of rainforest, or for £70 you can save an acre of Brazilian rainforest courtesy of Cool Earth (coolearth.org), the charity partly founded by sportswear magnate Johan Eliasch, who in 2006 bought 400,000 acres of rainforest, prompting President Lula of Brazil to stress: 'The Amazon is not for sale.'

Actually it is, along with tracts of wilderness in any cash-strapped country. I was recently offered a timeshare in South Africa's Kruger National Park (chimpedenresidentialclub.com). The information was full of comforting promises about environmental preservation, but more room was given over to the five-star accommodation. Increasingly, wildlife philanthropy crosses with eco tourism. Not a necessarily helpful hybrid. Similarly, private enterprises from developed countries buying up land from developing nations which then implement draconian conservation policies leave themselves open to the charge of eco colonialism.

Newer private conservation schemes refute eco-colonialism charges by leasing land rather than buying it or working with the local community and evaluating the rainforest properly in terms of natural capital so that the host country receives a fair price; Canopy Capital recently bought 370,000 hectares of pristine forest in Guyana with the Iwokrama reserve, earning plaudits from Greenpeace. Look for evidence of community conservation (divesting power to the local population to manage) and evidence that the community has been properly compensated.

Is it ever right to own a bit of the developing world and then set it aside for conservation? Probably not. But it is inevitable. There is, sadly, not the sense of urgency among governments to invest in public conservation (the UK's private Woodland Trust plants more trees than the government's Forestry Commission), and when deforestation causes 30 per cent of total carbon emissions in the atmosphere, at least chequebook conservationism doesn't have to wait. Is there anything noble about it? Slightly. It is still easier to pave over paradise than to buy and protect it.

lucy.siegle@observer.co.uk