Brazil's Supreme Court on Wednesday upheld state laws that revoke tax incentives for farmers who complied with the Amazon soy moratorium, a voluntary agreement credited with significantly reducing deforestation in the region. The court also affirmed the constitutionality of the pact itself, creating a complex legal landscape that may weaken its future effectiveness.

In January, major grain traders withdrew from the nearly two-decade-old soy moratorium after top soy-producing states enacted legislation to remove tax benefits for companies adhering to the agreement. This pact had barred the purchase of soy grown on Amazon land deforested after July 2008.

Brazil is the world's largest soybean producer, with a substantial portion of its crop cultivated in states within the Amazon biome. The Amazon rainforest plays a vital role in global climate regulation, and scientists warn that increased deforestation could accelerate global warming and disrupt agriculture worldwide.

The soy moratorium, launched in 2006, was a voluntary commitment supported by major soy traders and later endorsed by the Brazilian government. Farmers, however, argued it was more restrictive than national environmental laws, which permit a certain percentage of land clearing. The moratorium banned any deforestation, even when legally permissible.

A study published in the journal Science indicated that the moratorium reduced deforestation in risk areas by 35% in its first decade without impacting productivity. The study projected that its end could lead to up to 1.4 million hectares of deforestation in the next decade.

Environmental groups expressed concern over the ruling. Greenpeace Brazil noted a contradiction between the court's recognition of the moratorium's environmental importance and its validation of state laws that could undermine its impact. The Brazilian Association of Vegetable Oil Industries, ABIOVE, acknowledged the ruling provides legal certainty for sustainability commitments but referred to the moratorium in the past tense, suggesting its revival is unlikely.

Soy producer associations in states like Mato Grosso, which had opposed the moratorium, viewed the ruling as reinforcement of state governments' authority to counter private-sector environmental restrictions that extend beyond legal requirements. They indicated a continued opposition to similar future agreements.