How land-use choices affect biodiversity and the global climate

Over the past 50 years, Brazil has become one of the world’s agricultural giants. Becoming one of the world’s leading exporters of soy, beef, coffee and sugar has significantly boosted its economy and placed the country at the center of the global food system. This agricultural development, however, comes at a cost.

The expansion of agriculture has led to widespread conversion of natural vegetation to pastures, croplands and forest plantations. Much of this expansion has occurred in areas critical to biodiversity conservation and terrestrial carbon storage. In the last 40 years alone, agricultural land has increased by around 109 million hectares, an area almost twice the size of mainland France. Brazil is home to some of the most important biodiversity hotspots in the world. At the same time, its ecosystems serve as critical carbon sinks, storing large amounts of carbon essential for climate change mitigation. Continued pressure from agricultural expansion highlights the urgent need to reconcile production with biodiversity conservation and carbon sequestration.

Our new study explores how future changes in land use in Brazil could affect biodiversity, the global climate and the agricultural economy by 2050. We consider two shared socio-economic pathways (SSPs), each describing a distinct potential future for the world and Brazil. Among these, SSP3 depicts a scenario characterized by regional rivalry, heavy reliance on fossil fuels, strong nationalism, and significant challenges in climate change mitigation and adaptation. In this scenario, Brazil’s agricultural land is expected to continue to expand due to rising food demand and modest improvements in agricultural yields. In contrast, SSP1 represents a sustainable future, emphasizing proactive climate mitigation and adaptation, adoption of clean energy, and protection of natural ecosystems. Under SSP1, Brazil’s agricultural land is expected to contract, thanks to reduced food demand and substantial improvements in yields.

Where agriculture develops

Under the SSP3 scenario, approximately 52 million hectares of natural land are converted to agricultural purposes to meet growing food demand, affecting all biomes in Brazil, regions that encompass large ecosystems with similar climatic or ecological conditions and specific vegetation type. This expansion leads to a projected 28% increase in agricultural income between 2025 and 2050, but it comes with significant environmental trade-offs. Loss of natural vegetation is expected to release a total of 12 gigatons of CO₂ over this period. On average, this would amount to 0.5 gigatonnes per year, which is higher than Brazil’s annual emissions rate from land use during the 2010s. Biodiversity would also be affected, since around 70% of the mammal species we studied, including the maned wolf and the howler monkey, would lose their habitat over the same period.

Our results show that environmental impacts depend not only on the scale of agricultural expansion, but also on where it takes place. Deforestation must be avoided in the Amazon and Atlantic rainforest, as both biomes are rich in carbon and biodiversity, and clearing them has a major impact on both. In these biomes, whether deforestation occurs at the forest edge or deep inside, it releases significant amounts of CO₂. For biodiversity, however, location is decisive: deforestation in areas very rich in biodiversity (including indigenous lands and conservation units, officially designated areas in Brazil that benefit from legal protection) disproportionately threatens species with restricted habitats. For example, Saguinus bicolor, a primate species with one of the smallest habitats in the Amazon, is expected to lose more than 7% of its remaining range, further shrinking an already limited area.

Ecosystem restoration with low economic loss

In the SSP1 scenario, falling food demand is expected to lead to the abandonment of agricultural land, freeing up large areas for restoration to their natural state. Between 2025 and 2050, agricultural income is expected to fall by 31%, but this comes with positive environmental consequences. More than 12.4 gigatons of additional CO₂The equivalent of around five years of EU emissions from fossil fuels and industry should be sequestered, making a major contribution to climate change mitigation. Additionally, the habitats of two-thirds of the mammal species we studied are expected to expand.

Interestingly, these results indicate that land restoration around remaining biodiversity- and carbon-rich areas could provide substantial environmental benefits with relatively modest agro-economic losses. In these areas, restoration would result in a loss of farm income of only $5 to $10 per ton of carbon gained. For comparison, the European Union’s Emissions Trading System currently values ​​carbon at around $70 per tonne, suggesting that strategic reforestation in Brazil could be a very cost-effective climate change mitigation strategy. This is particularly relevant as Brazil recently launched its own Greenhouse Gas Emissions Trading System (GHES). In addition to increasing carbon sequestration, reforestation of these areas would generate substantial co-benefits for biodiversity, creating a synergistic opportunity to advance both.

Lesson learned for a more sustainable future

Reconciling agriculture with biodiversity and the climate is essential to Brazil’s sustainable transition. Future changes in food demand and agricultural yields will determine the amount of land the country devotes to agriculture and, by extension, the pressure placed on its ecosystems. The more land production requires, the greater the impacts on biodiversity and carbon storage.

If expansion is inevitable, several strategies can help reduce environmental consequences. Agricultural expansion must be carefully planned, avoiding areas rich in carbon and biodiversity, and must not include deep deforestation of forests. At the same time, restoration efforts focused on areas rich in biodiversity and carbon can provide substantial environmental benefits at relatively low economic cost.

Brazil’s path to sustainable land use ultimately depends on two key questions: how much land is needed and what land should be used.

This article is republished from The Conversation under a Creative Commons license. Read the original article.