Roads: helpful here, harmful there

Print Friendly

Getting on the high road?

Do you love roads or hate them? If you’re an environmentalist, chances are you’re at least highly skeptical. Roads are famous for bringing settlers, forest destruction and farms to natural areas that are often inappropriate for sustainable agriculture.


Brown dirt road passing small home and cutting through treed area.

Near Manaus, Brazil, Photo: Julio Pantoja / World Bank World Bank Photo Collection
In the Amazon basin, locals harvest forest products like mandioca, coconuts and cocoa to eat and sell.

But the agricultural industry, and people who promote farming as an antidote to hunger and poverty, see another side to roads. Farmers who want to do more than feed their families need good roads to bring in advisors, fertilizer and seeds, and take crops to market.

Roads that are muddy or impassable can make transport so expensive that cash cropping makes no sense.

This week, the journal Nature prints a proposal to square this circle by developing a system to chart where roads are beneficial, and where they are harmful. As the authors wrote, “We propose that environmental scientists, planners, road engineers and other stakeholders carry out a global ‘road-zoning’ project to map areas that should remain road-free and those in which transport urgently needs improving.”

We emailed corresponding author William Laurance, a conservation biologist at James Cook University in Australia, to ask if the idea was “pie in the sky.” Not so, he wrote. “What we’re hoping to see produced is a tool that anyone can use to prioritize where and where not to put roads. Some stakeholders and nations will hopefully use it, but of course not everyone will.”

Roads and forest degradation in Rondônia (western Brazil)

The forest in the state of Rondônia was once almost as big as Kansas, at 208,000 square kilometers. According to the Nature study, more than 95 percent of deforestation, fires and atmospheric carbon emissions in the Brazilian Amazon occur within 50 kilometers of a road. Intact forest is deep green, cleared areas are tan (bare ground) or light green (crops, pasture, or occasionally, second-growth forest). Between 2000 and 2009, deforestation in the state grew from 30,000 past 51,000 square kilometers. Rollover to see the change by 2009.
Images: MODIS/Terra, NASA Earth Observatory

Although rampant road-building in tropical forests has lead to significant forest destruction, “The situation is slowly improving,” Laurence wrote to us.  “Big highways tend to be more controlled than secondary and tertiary roads. Many of these smaller roads are being created illegally in remote areas, and that’s something that needs to be cracked down on.”

“We’re hoping to see a tool that anyone can use to prioritize where and where not to put roads.”

Roads really matter, says Lisa Naughton, a professor of geography at the University of Wisconsin-Madison, who studies development and conservation in the tropics. When the Interoceanic Highway was recently completed in the Peruvian Amazon, she says, “It utterly transformed the relationship between people, land and forests. The long-term efforts of Peruvian conservationists to promote sustainable agroforestry and non-timber forest-product harvest (such as Brazil nuts) were rapidly undermined as the road brought in large-scale agriculture, and deforestation has accelerated.”

Building in the zone

Rather than establish mandatory zoning, Laurance envisions a map that helps planners, politicians, agricultural interests and conservationists guide development while protecting indigenous lands, biodiversity hotspots and other sensitive areas.

The balanced approach, he says, “is a potential advantage … . We’re not saying to simply stop all road building. We’re saying let’s stop some of the environmentally destructive roads … while at the same time focusing road building where it’s likely to have the biggest economic and social benefits.”

According to projections, the demand for food will soar by 2050, due to a rising population with a growing desire for meat. According to the Laurance study, an extra 1 billion hectares (which happens to be the size of Canada!) will be needed for crops and grazing land. Much of that will have to take place on wild land.


Food consumption and population increase in parallel through 2050.

Consumption of cereals — primarily maize, wheat, rice and soybeans — is expected to soar along with continued population growth and prosperity.

But boosting agricultural productivity could supply some of this food, slowing the destruction of wild lands and wild creatures.

Roads: Farmers’ best friend?

It’s impossible to imagine advanced agriculture in developed countries without good roads. Do roads play the same role in developing nations? “It’s funny—this is one of those ideas that seems to be widely accepted but doesn’t have a lot of formal evidence,” wrote Laurance. “I know because we’ve looked. … In scientific terms, there is a scattering of papers and books that use econometric approaches to argue that road improvements benefit agriculture — reducing waste, increasing market access and improving profitability. But … there doesn’t seem to be much debate about this among those who study such things.”


Photo shows person on loaded bike riding along muddy road that sweeps uphill and to the left, in the midst of a grain field.

Photo: © Curt Carnemark / World Bank Photo Collection
Roads like this one in Morocco are not conducive to modern, profitable farming. Could better roads help local people while reducing the pressure on wild lands?

Even if zoning for roads makes sense, practically speaking, could it work? Although national governments “have legal sovereignty over their lands, there are very powerful economic forces at work to promote road building — some of which are clearly inadvisable environmentally,” Laurance responded. The road-zoning scheme “could be used by governments and also conservation groups and other stakeholders to facilitate road planning.”

“The call for ecologically-informed road zoning is appropriate but faces major political challenges,” says Naughton, director of the Land Tenure Center at UW-Madison. “Perhaps some of the major roads funded by multi-lateral development agencies can be planned to lower social and biodiversity impacts. But there is ever more private and unilateral international funding available for road-building. More fundamentally, road-building has great political importance in a place like the Amazon — even if a road makes little economic sense, there are often strong political incentives to build it.”

But Laurance notes that, in the face of a proposal to push a road through a wilderness, “With a good road-zoning scheme, you could say, ‘Hold on a minute — that’s an environmental red-zone, the last place you’d want to construct a road. Let’s consider another route or perhaps even forego a new road altogether. Roads profoundly influence the spatial footprint of human activities, and so it’s crucial to focus explicitly on them.”

— David J. Tenenbaum


Terry Devitt, editor; Emily Eggleston, project assistant; S.V. Medaris, designer/illustrator; David J. Tenenbaum, feature writer; Amy Toburen, content development executive


  1. A global map for road building, William F. Laurance and Andrew Balmford, Nature, 21 March 2013.
  2. The power of rural infrastructure for developing nations
  3. Deforestation in the Amazon: Satellite timelapse
  4. The Amazon Road: Paving Paradise For Progress?
  5. From nothing to nowhere? A different take on the Amazonian highway
  6. Global food demand: Get the facts!