The Gran Chaco Pathways Towards a Sustainable Future 2025

The Gran Chaco – a critical water reservoir and carbon store BOX 10 A critical water reservoir The Gran Chaco is traversed by major rivers, including the Grande, Otuquis, Agua Dulce, Pilcomayo, Bermejo and Salado, which support agriculture and local livelihoods despite seasonal variability in water availability. Groundwater resources are also crucial, with freshwater deposits in deep aquifers in the west. However, in central and eastern Chaco, shallow aquifers often suffer from salinity due to evaporation and vegetation transpiration, limiting potable water access for communities and agriculture.42 Potable water scarcity in the Gran Chaco is worsened by high evaporation rates and arsenic contamination in aquifers and deforestation. These challenges exacerbate the difficulties faced by local communities and agricultural practices, highlighting the critical need to protect potable water resources for sustaining production, conserving vital resources and building resilience against climate variability.43,44,45A vital carbon store The Gran Chaco plays a vital role in climate change mitigation through carbon storage in its soil organic carbon (SOC). High SOC levels enhance CO2 sequestration, support soil health and boost agricultural productivity. Studies show that nearly one-third of global SOC stocks are in forested areas, underscoring the importance of regions like the Gran Chaco.46 Although SOC levels vary, all countries within the biome exhibit high SOC concentrations: Argentina: the dry and wet Chaco together contain 25% of the country’s SOC, averaging 48 tonnes per hectare (t/ha) in the dry Chaco and 59 t/ha in the wet Chaco.47 Bolivia: SOC levels range from 96 to 124 t/ha across diverse forest types.48 Paraguay: hydrophilic forests store about 55 t/ha, while dry forests hold 46 t/ha. The wet Chaco is particularly crucial for carbon storage and biodiversity.49 Protecting these carbon reservoirs offers opportunities to incentivize sustainable land management, contributing to biodiversity conservation and climate change mitigation. 3.3 Land-use change, vulnerabilities and socio-economic consequences The expansion of unsustainable agriculture has significantly increased deforestation rates, particularly in the semi-arid Chaco Forest, one of the world’s regions to suffer the greatest deforestation in recent decades.50 Between 2001 and 2023, the biome lost over 13 million hectares of forest cover (see Figure 10), a change closely tied to land-use alterations. This has led to increased carbon emissions in the region (see Figure 11) at a critical moment in the wider context of global climate change. According to a report published by the United Nations in October 2024, a continuation of current policies could lead to global warming of up to 3.1°C over the course of this century51 – double the 1.5°C threshold established by the Paris Agreement a decade ago. 28 The Gran Chaco: Pathways Towards a Sustainable Future