Once a rainforest is gone, it's gone forever, right? Not necessarily. Katherine Rowland surveys the brave new world of restoration ecology: the art of breathing new life into dying lands.
Ever since Aldo Leopold warned of a world irrevocably diminished by human appetite, conservationists have urged that we "act now, before it's too late". But what if nature's end was not a foregone conclusion? Imagine if we could recreate lost rivers, meadows, rainforests even...
A few years back this would have been wishful thinking. But the science of restoration ecology is a fast moving one. Across the globe, from the Aral Sea to the arid Sahel, ambitious programmes to revive and recreate degraded ecosystems are challenging the assumption that once destroyed, nature is gone for good.
They are boosted by the growing realisation of the value of 'ecosystem services' - the tangible and intangible goods derived from nature, which add up to $72 trillion of benefits to the world economy every year. That's the conclusion of economist Pavan Sukhdev, who led a series of landmark studies for the UN on 'the economics of ecosystems and biodiversity', or TEEB for short.
Sukhdev's analyses suggested that restoring ecosystems can yield benefit-cost ratios of around 75-to-1. Factor in their "invisible" components, such as contributions to human health and wellbeing, and the benefits of restoration may even exceed quantification, he says.
According to Dax Lovegrove, Head of Business and Industry Relations for WWF-UK, "There's a slowly dawning recognition that protecting natural capital serves to future-proof the economy."
If you want to know what that looks like in practice, go to central Asia. For decades, the Aral Sea has shouldered the dubious distinction of being among the most degraded watersheds on earth. Years of aggressive agricultural expansion to boost Soviet cotton exports had reduced what was once the world's fourth largest freshwater lake to an arid wasteland. Images of fishing boats adrift in sand, and ports marooned miles from the sight of water, became clichés of environmental destruction.
Over the last decade, though, the tide has turned. An initiative launched in 2001 by the Kazakh government and the World Bank is revitalising the North Aral. The waters have returned to wide swathes of the lake bed, and local fishing fleets are at work again. As World Bank President Robert Zoellick said in 2009: "The return of the North Aral Sea shows that man-made disasters can be at least partly reversed."
As the Aral's tides were rising, so a green wave was starting to sweep across Africa - not of water, but of trees. Its aim: to push back the Sahara by planting a "Great Green Wall" from Djibouti in the east to Dakar in the west. With nearly US$2 billion in funding from the World Bank's Global Environmental Facility, the initiative has so far successfully planted over 50,000 acres in Senegal.
Rolling back the Sahara may sound like a vain hope. But today's vast desert is a recent phenomenon. In prehistoric times, the Sahara was relatively lush. Even in the Roman era, parts of what are now desert were known as the breadbasket of the empire. Planting trees may not restore the desert to the verdant hills of prehistory, but it could halt and reverse what was once seen as an inevitable process of desertification. So it's no surprise that, as land management specialist, Chris Reij says, "the idea of re-greening Africa is spreading like bushfire". He contrasts that enthusiasm with the 1970s, when "the conditions then were so bleak, it was impossible to imagine what could be achieved".
Reij works with the Africa Regreening Initiative, which supports small farmers, mainly in the western Sahel, to protect and manage trees growing in and around their fields, effectively transforming whole landscapes into 'agroforestry parkland'. Satellite imagery from the US Geological Survey suggests that this has resulted in five million hectares of new tree growth in Niger alone. Tentative evidence is even emerging of higher crop yields in the newly greened areas, as the trees help prevent soil erosion and conserve water.
The notion of reforesting desert may not be as far-fetched as it sounds. Since 1982, China has planted more than 40 billion trees along the southern edge of the Gobi Desert, and plans to cover a further 100 million acres by 2020. This will not only generate newly forested areas the size of Germany, but also contribute to the emerging vitality of the Loess Plateau, which lies to the south. Home to more than 50 million people, this is one of the poorest regions in China, after centuries of over-farming left it "the most eroded place on earth". But a project launched in 1995 by the World Bank and the Chinese State Forestry Administration is slowly transforming the region into a landscape of terraced tree belts and newly fertile fields. As a result, says the Bank, average household incomes have doubled.
Rainforests, meanwhile, have long been considered irrecoverable once destroyed. But new growth in depleted soils is offering evidence to the contrary. In Costa Rica, a project begun by the late plant physiologist Carl Leopold (grandson of Aldo Leopold) has successfully recreated rainforests in degraded cattle pastures. In Borneo, microbiologist Will Smits has similarly replanted rainforests in clear-cut areas. Motivated by wanting to develop habitats for orangutans under threat from deforestation, Smits discovered that ecological rehabilitation would not only benefit dispossessed apes, but improve human livelihoods, too. Working with the local community, Smits introduced more than 760 species of trees onto 2,000 hectares of logged land, effectively producing a new ecosystem: a rainforest built by man. The new growth has brought on increased cloud cover and rainfall has risen by 30%.
But not all landscapes are re-created equal, and doubts abound over whether man-made versions can ever replace the real thing. Ecologist David Moreno-Mateos of Stanford University warns that restoration often falls short of full recovery. "Every ecosystem is different, and once destroyed they can take centuries to recover." he says. "There's a long way to go before we understand how to make restoration successful."
Gauging "success" is not just a challenge for scientists, says Hugh Knowles of Forum for the Future. "When comparing ecosystems we often use a narrow definition of 'better'", he says, "[which] tends to assess their function based on how they serve our needs." Lovegrove agrees: cultural, social and economic factors "complicate how we measure the value of an ecological loss or an ecological gain".
That doesn't stop some from dreaming on a grand scale. Among them is ecologist Josh Donlan, Director of Advanced Conservation Strategies. He argues that restoration is, by definition, an exercise in history and determining what 'original' means in the first place. "It's not just about stopping extinction," he says. "We can look back in time to recreate nature." In what he calls "pleistocene rewilding", Donlan proposes to reintroduce species "that have been absent from the ecosystem for thousands of years". Large mammals such as lions and camels were a vital part of North America's landscape before humans arrived some 10,000 years ago. "We know that big creatures tend to be very important to ensuring biodiversity in the long run," says Donlan, who believes such initiatives could bring economic bounties in the form of tourist dollars and land management jobs. "Just look at the names of our sports teams and cars: we love big animals."
Wild HorsesWhile Donlan's schemes may seem far out, less grandiose variations are already in place. Wild horses and aurochs now graze in the Netherlands. The grey wolf, once hunted to the brink of extinction, now roams Yellowstone Park. Now a new initiative, including WWF Netherlands and Ark Nature, has launched a number of pilot areas in which 'rewilding' [the restoration of natural processes] and economic recovery are linked. Targeting abandoned land, Rewilding Europe works with local governments and community groups to repair degraded ecosystems and introduce "wilderness-based" business activities, such as eco-tourism and natural product industries. Neil Birnie, the group's business director, says: "There's a common misconception that rewilding is an attempt to remove people from the environment. It's not at all like that." Rather, he maintains rewilding can serve to harmonise human activity, economic growth and nature.
This contention, while optimistic, may very well be the benchmark for restoration initiatives as they grow in scope and ambition. "Nine billion humans on the planet will mean we need to figure out new social and economic models that integrate people and ecosystems," says Knowles. The large-scale projects currently underway, the "pockets of progress," as Lovegrove calls them, may offer a glimpse of what the world could look like. Perhaps it is reason to rework Oppenheimer's adage: "We are become as gods, restorers of the world."
Katherine Rowland is is a journalist based in New York City; her work on health and the environment has appeared in Nature and the Financial Times, among other publications.
Additional research by Eleanor Devenish.