Balancing Climate and Biodiversity: Assessing the Socioeconomic Impacts of the 30-by-30 Target with Climate Warming Constraints

Abstract: Limiting global warming to 1.5°C will require significant land-use change. Various post- Paris Agreement strategies are rooted in land-based CO₂ removal. However, these strategies introduce potential mismatches with biodiversity conservation policies. Given this, this study evaluates the compatibility between the UN Kunming-Montreal Global Biodiversity Framework’s “30-by-30” 
target—protecting 30% of land and oceans by 2030—and two climate change scenarios: “Current 
Trends” (CT), which extrapolates present climate policies through the century, and “Accelerated 
Actions” (AA), which seeks to stabilize average temperatures at 1.5°C. 

A multi-sector computable general equilibrium model (MIT Economic Projection and Policy Analysis) is employed with a 30-by-30 target that protects biodiversity-rich natural forest and grasslands while prioritizing subsidy-based transition to these land types. Subsequently, the analysis follows with a land use downscaling disaggregation model (Demeter) of 0.5 x 0.5 resolution projection to capture the spatiotemporal shifts resulting from the combined 30-by-30 and climate policy effects. The 30-by-30 biodiversity target is evaluated across an ensemble of socioeconomic scenarios and Demeter 
parameters to analyze their sensitivities to various climate targets and underlying downscaling 
model constraint characteristics. 

Under CT and AA, India and the Middle East will experience the largest GDP losses, up to tens of billions of dollars, as a result of combining the 30-by-30 target. Meanwhile, Brazil and Australia and New Zealand will experience billion-dollar magnitude growth. Outputs further magnify the distributional effects of the 30-by-30 target, where the Middle East and India will experience substantial food price increases ranging from 5-600% in certain agricultural products. These results highlight disparities for regions with deficient natural forest and grassland cover, but also the potential comparative advantage for strong agri-livestock regions that would benefit from increased food exports. 

Overall, these socioeconomic insights into the effects of a dual biodiversity-climate intervention can guide policymakers to develop complementary strategies that regulate policy ramifications,
including food-price impacts and agriculture-induced deforestation.