Measuring What We Manage: Methodological Robustness and Regional Consistency in Brazil's ABC+ Low-Carbon Agriculture Accounting System

Brazil's ABC+ Plan sets, for each of ten low-carbon agricultural technologies, two parallel 2030 targets- a physical target (area, herd size, or adoption volume) and a climate target (Mg CO2 equivalent mitigated). Regional climate-target figures are official accounting estimates from predetermined emission factors applied to observed adoption, not independently measured outcomes. This study assesses the regional consistency and methodological robustness of this official accounting -- not the Plan's actual mitigation effectiveness -- by structuring official data on adoption, expansion, accounted mitigation, and financing across Brazil's five macro-regions (2020-2025), interpreted through a narrative literature review. Because technologies differ in physical unit, mitigation pathway, and time horizon, cross-technology comparisons are presented as descriptive accounting patterns, not a common performance metric; regional shares reflect distribution, not region-specific effectiveness. Results show systematic divergence between physical- and climate-target attainment within most technologies -- 3.3-fold for integrated crop-livestock-forestry and 4.3-fold for agroforestry systems, for example -- and that four biophysically distinct technologies share one fixed accounting coefficient (3.79 Mg CO2eq ha-1 yr-1). Rural credit shows no clearly expressed proportional relationship with accounted mitigation for any technology. We conclude the accounting would benefit from technology-specific emission factors, region-adjusted benchmarks, and greater transparency, and that validating these estimates against field-measured mitigation remains an open task.