Rainforests are ‘worth more alive than dead,’ according to science — and economics

November 15, 2019

By Adam Wernick

Rainforest biotic pump — Through a mechanism called the biotic pump, rainforests are able to generate rain that falls back on them and can even influence faraway climates.
Thomas Marent/Flickr

Rainforests are treasures of biodiversity, and their ecosystems benefit the entire planet. But the Western economic model tends to view them as most valuable when they’ve been logged, mined or turned into agricultural land. As a result, rainforests around the world are rapidly disappearing.

In his new book, “Rainforest: Dispatches From Earth’s Most Vital Frontlines,” author and conservationist Tony Juniper argues that leaving rainforests intact offers more, not less, economic benefit — while helping to maintain the planet’s climate stability.

Economic development means many things to many different interest groups and can be compatible with long-term conservation of the forest, Juniper says. “But if the decision-makers…think that economic development that involves the removal of the forest and its replacement with fields, farms, hydroelectric dams and mines is sustainable, then I would beg to differ.”

“It’s really a question of what kind of economy we think can coexist with these ecosystems,” he continues, “because the Indigenous people have been there literally for thousands of years, and they’ve been sustaining their societies and their civilizations through an economic system that regards the forest as worth more alive than dead.”

In the case of the Amazon, Juniper notes, the rainforest is approaching a tipping point whereby so much forest will have been cleared that what is left will no longer function properly because the system has been degraded beyond the state that enables it to keep going.

“This is particularly the case in relation to rainfall and the extent to which it will remain a wet forest after a certain level of clearance and fragmentation that causes [its] finely-poised hydrological system to break down in ways that cause it to turn into a savanna, or even into a grassland,” Juniper explains. “When it’s in those states, it will provide a different set of values to the world than those which it’s providing now. The values that we’re getting at the moment are important for the entire planet from the point of view of economic development, literally.”

The carbon currently held in the world’s rainforests benefits the entire world economy, Juniper insists. “If we start to degrade that function in order to get short-term economic growth of the Western kind, then I do think that would be a mistake.”

In addition, rainforests create their own internal weather systems through a phenomenon called a “biotic” pump. These systems, in turn, affect weather and climate in places far beyond its borders.

“Rainforests, obviously, have a lot of water falling upon them,” Juniper says. “Less appreciated is the amount of water coming out. Across the Amazon, each day, some 20 billion tons of water are being evaporated into the atmosphere. … [W]hen that vapor goes up into the air on the warm rising air currents that are being driven by the sunshine, it gets up to high altitude, and when it [reaches] high altitude, it condenses and turns back into tiny water droplets because of the cooler conditions.”

When the vapor turns from a gas back into a liquid, it collapses in on itself, occupying a smaller space of atmosphere. This creates a vacuum that causes a “colossal, powerful updraft to come from beneath,” Juniper explains. “So the condensation is really a pump that’s driving the air currents skywards. Then you get these towering, great storm clouds over the forest, which are obviously creating vast amounts of rainfall, but they’re also driving the circulation of the Earth’s atmosphere at a much bigger scale.”

“This great system is only now really just beginning to be appreciated, but it has huge implications for the entire world because [some of] the moist forests that run around the equator…are pushing out water that’s traveling thousands of miles.” Juniper says. “Indeed, during the course of my research, I spoke to American researchers who were finding connections between the forests of Central America and the Amazon and the grain fields of the Great Plains of North America in the Dakotas and in Manitoba in Canada — water traveling that far, which has its origins over the tropical rainforests.”

Carbon and water are two ways rainforests are connected to global climate and weather systems. A third way is nutrients.

In a rainforest, nutrients “are being consumed in a voracious way because of the way the plant growth is so rapid and so lush,” Juniper says. “[And] in areas of tropical rain forests that are on very ancient rocks, the nutrients were used up tens of thousands of years ago. So, in order for the forest to continue to function, nutrients need to come in from elsewhere.”

Surprisingly, the input of nutrients comes from one of the driest places in the world: the North African Sahara desert.

In the Sahara, there is a place called the Bodélé Depression where giant dust storms occur regularly, kicking up material into the atmosphere. Satellite photographs show this dust plume traveling at high altitude across the Atlantic, and some of this material falls out over the Amazon, bringing with it, for example, phosphorus, an essential plant nutrient that helps the rainforest system function.

“I think the more we understand about all of these things, the more we can see the interconnectedness of how this entire system is working,” Juniper says.

In his book, Juniper cites several success stories — places where sustaining the forest has led to economic and environmental benefits. One of these is Costa Rica, which, Juniper says he found “quite inspiring.”

“Costa Rica sought a route toward economic development that not only didn’t involve deforestation but included putting much of the forest back,” he explains. “And if you look at that country, between the 1980s and now, the forest cover has doubled. So has the country’s per capita GDP [gross domestic product]. And this was through the realization, literally, by the finance ministry in that country 30 years ago, that the forest was worth more for the nation alive than dead.”

The country’s power sector relies on hydroelectric dams powered by rivers filled with forest rainfall; they realized that they had vast quantities of clean water coming out of the forest that didn’t require water treatment; and “the real visionary opportunity they spotted” was ecotourism, Juniper says.

“Putting all these things together, they’ve managed to hang on to the forest, expand it, at the same time as growing their agricultural sector,” he notes. “They are a very major exporter of coffee, of pineapples and bananas. … and in the future, they may be able to participate in carbon markets, too.”

“They’ve blended all of these economic dimensions into a plan which is really about keeping the forest there for the national good,” Juniper says. “So, if you want to have development into the future, keep and expand the forest. That’s what the science and indeed the good practice is now telling us.”

This article is based on an interview that aired on PRI’s Living on Earth with Steve Curwood.