Home ScienceEnvironment In Landslide-Prone Colombia, Forests Can Serve as an Inexpensive Shield

In Landslide-Prone Colombia, Forests Can Serve as an Inexpensive Shield

Only aerial footage captures the true scale of the horror: Houses have been flattened, roads ruined, and everything looks like it’s been covered in a film of dark-brown syrup. A sludgy scar down the mountainside shows the trail that a hunk of dislodged rock and earth took in the moments before it upturned the lives of dozens of homeowners in the Dosquebradas municipality of Colombia.

“It felt like the whole world was coming down,” Maria Juliet Lugo, a survivor of the landslide that killed 14 people and left dozens of others hospitalized, told Al Jazeera after a rainstorm hit central Colombia this past February.

Such scenes are becoming all too familiar across the country. Colombia’s undulating, rain-soaked topography makes it a landslide hotspot. Each year, hundreds of landslides wrack the nation; some 30,730 hit between 1900 and 2018. Not all leave untold destruction in their wake, but many do.

In 2017, a downpour in Mocoa, capital of the department of Putumayo, triggered hundreds of landslides and kicked off a debris flow through the city streets, killing 333 people. And in May 2019, a series of mudslides that barreled into the Vía al Llano, Colombia’s major highway, cut the country in two, according to reporting by The Economist. For months, mud and rocks severed supply chains and cut off 1.7 million people living in Colombia’s farming heartland, causing food shortages and rocketing prices.

But to call these purely natural disasters would be wrong; the country’s landslide vulnerability has a man-made twist. Poor urban, land-use and development planning intertwine with geomorphological factors and heavy rainfall to create a hazardous cocktail. But growing evidence points to two other forces adding to the danger: deforestation and climate change.

Fifty-two percent of Colombia’s landmass is covered in forest. Like big, green umbrellas, when standing, the forest canopy provides natural protection from the wind and rain. The underground architecture of deep roots acts like living avalanche barriers, locking loose soil in place and providing a lifesaving service to people downslope.

But when forests disappear, so does this natural buffer. After illegal ranchers or industrial farmers hack down forests or burn natural vegetation, they leave behind an unstable landscape primed for mass movement. According to one study led by Grima, landslides in Colombia are six times more likely to happen on non-forested than on forested land.

So it’s bad news for landslide risk that between 2001 and 2020, Colombia lost 5.7% of its tree cover, an area of 4.66 million hectares (11.52 million acres). And it’s more worrying still that these high deforestation rates show little sign of relenting in recent peacetime years.

Meanwhile, scientists warn that matters are likely to worsen as climate change turbocharges rainstorms and interacts with deforestation in unpredictable ways. Many paint grim forecasts of intensified deluges battering into naked mountainsides that have been stripped of their natural landslide-mitigation systems. A recent global map pinpoints where more extreme precipitation will slam into unprotected mountains, vulnerable to deforestation, and large swaths of the Colombian Andes lose their green cover.

There may be a way out. Scientists and policymakers are increasingly arguing that targeted forest protection, and in some cases restoration, could provide communities and infrastructure with resilience against climate-worsening landslide risk. And it could also help stanch Colombia’s biodiversity loss.

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