What drives and halts tropical deforestation? Analyzing 24 years of data

With the climate crisis in full swing, world leaders have made pledges to halt and reverse forest loss by 2030. In a new meta-analysis, researchers synthesized the findings of 320 studies about what is associated with more or less deforestation in the tropics.

According to the study, published in the journal Review of Environmental Economics and Policy, converting land for farming and raising cattle is a significant driver of deforestation. In the Amazon, for example, 70% of deforestation has been linked to clearing for cattle pastures.

Building more roads and expanding cities into forests almost always leads to more deforestation in tropical areas. The more accessible a forest is, the more likely it is to be cut. Population growth also means more people cut forests for housing and farming.

“They’re things that many people already know,” study co-author Jonah Busch of Conservation International told Mongabay in an email. “But we can state them with the confidence that comes from a comprehensive, systematic, quantitative, review of hundreds of studies over 24 years.”

On the flip side, forests on steeper, sloping hills and higher elevations are subject to less deforestation because they’re harder to access. Stronger protections for parks and nature reserves also help slow deforestation, as does better law enforcement and bans on logging.

Indigenous territory or land managed by Indigenous peoples have less deforestation too, the study found. According to another report, protected areas and Indigenous territories in the Amazon Rainforest experienced just one-third the amount of primary forest loss as non-protected areas.

The study found deforestation rates are generally lower in forests with commodity certification programs such as shade-grown coffee or sustainably produced palm oil initiatives. Paying forest communities and landowners to preserve forests is also effective.

The researchers also found a link between wealth and deforestation. “Greater wealth locally results in more deforestation, because richer people are more able to buy machines, access credit, or hire workers to clear trees,” Busch said. “We also see that when money comes into an area from the outside, whether through public anti-poverty programs or remittances, deforestation tends to increase.”

However, this isn’t the case with payments for ecosystem services, where communities or landowners are paid to keep forests standing. Paying people to keep the forest intact generally works.

“There’s relatively less evidence, but still important to note that livestock and timber drive deforestation, while payments for ecosystem services (PES), Indigenous stewardship, forest law enforcement, among other policies, slow it down,” Busch said.

Heat was associated with more deforestation. “If I had to guess,” Busch said, “I’d think that higher temperatures may be making forests more susceptible to fire as a means of clearing forest.”

Altogether the studies produced more than 15,000 results from investigating the effects of more than 3,400 potential drivers of deforestation and reforestation. The researchers categorized each driver into groups like agriculture, infrastructure, policy, poverty, etc.

Busch called this analysis a “mammoth undertaking,” in which he and co-author Kalifi Ferretti-Gallon combed through “hundreds of studies and tens of thousands of data points and distilling it all into essentially a single picture.”  A database of results from all studies examined by their meta-analysis is now publicly available. The authors say they hope to update their analysis every five years.

This study was itself an update to a previous analysis published in 2017. The new research included more studies from Africa and Asia and also larger study areas. However, some significant gaps remain. Few studies have examined how mining, wildfires, policy changes, or land speculation affect deforestation, especially outside Latin America.

This study “comes at a time when we need strengthened and more persuasive evidence-based arguments to help political and business leaders to make the difficult decisions, to deviate from business-as-usual, and act on their commitments to halt deforestation and restore forested ecosystems,” Peter Graham, Managing Director of Policy & Research at Climate Advisers, who was not involved in this study, told Mongabay. “I expect that I will be using the findings of this study to support … accelerating and scaling up nature-based solutions to the climate and biodiversity challenges.”

The authors say they hope this study provides a starting point for identifying unanswered research questions and will inform decision-making.

“In the face of climate change which renders our forests both more critical and vulnerable, a comprehensive study is our roadmap to effective conservation strategies,” said co-author Ferretti-Gallon, a forestry researcher at the University of British Columbia’s Asia Forest Research Centre. “It is incumbent upon policy makers, corporations and conservation organizations to prioritize these and invest in sustainable practices as the planet’s future health relies on translating this knowledge into action.”

Banner image of a squirrel monkey near Yasuni National Park in Ecuador by Rhett A. Butler.

Beef is still coming from protected areas in the Amazon, study shows

Citation:

Busch, J., & Ferretti-Gallon, K. (2023). What drives and stops deforestation, reforestation, and forest degradation? An updated meta-analysis. Review of Environmental Economics and Policy, 17(2). doi:10.1086/725051

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