Evaluación del impacto de las emisiones de GEI en la rehabilitación vial en bosques tropicales mediante análisis de ciclo de vida

Abstract

This research evaluates the greenhouse gas (GHG) emissions generated during the rehabilitation of a road located in a highly intervened tropical forest in the department of Guaviare, Colombia, applying a Life Cycle Assessment (LCA) in accordance with ISO 14040 and ISO 14044 standards. The analyzed corridor corresponds to the San José del Guaviare – El Retorno – Calamar stretch, a road infrastructure project of great regional relevance that crosses ecosystems of high environmental sensitivity in the Colombian Amazon. The study encompassed the four methodological phases of LCA: definition of objective and scope, life cycle inventory, impact assessment, and interpretation phase. A cradle to gate approach was adopted, which considered the processes of input transportation, heavy machinery operation, terrain earthworks, granular subbase and base construction, asphalt paving, and drainage works execution. Two complementary tools were used for the quantification and modeling of environmental impacts: SimaPro® for the detailed quarterly analysis of the construction phase, and Athena® Pavement LCA for the simulation of the complete life cycle over 30 years. The impact assessment methodology applied was ReCiPe 2016 Midpoint (World 2010 H), through which four impact categories were estimated: Global Warming (GW), Mineral Resource Scarcity (MRS), Fossil Resource Scarcity (FRS), and Water Consumption (WC). This selection made it possible to characterize both the direct CO₂ equivalent emissions and the effects associated with the consumption of materials and natural resources throughout the project. The life cycle inventory results revealed that the greatest environmental impacts were concentrated in the first quarter of construction, a period dominated by earthwork activities and the high fossil fuel consumption of the heavy machinery employed. In subsequent quarters, the impacts were redistributed among the subbase, granular base, and paving processes. By extending the analysis to the 30-year horizon using Athena®, it was determined that the periodic maintenance phase represents 62% of the total accumulated emissions of the project, underscoring the relevance of this stage in the environmental footprint of road infrastructure. Regarding materials, cement, lime, and Granular A concentrated more than 60% of the total quantifie edemissions. In the comparison between tools, SimaPro® demonstrated greater detailed modeling capacity and flexibility for the analysis of individual processes, compared to Athena®, which offers an integrated perspective of the pavement life cycle. The total emissions of the project significantly exceeded the carbon capture capacity of the intervened area, with an estimated 289 to 1,818 forest hectares required to offset the emissions generated, a figure that evidences the magnitude of the climate impact of this type of project in tropical forest contexts. The study concludes by highlighting the importance of incorporating environmental sustainability criteria from the early planning stages of road infrastructure, as well as the need to strengthen and update local inventory databases to improve the accuracy and representativeness of LCA in Latin American tropical contexts.