Consideración del cambio climático en la evaluación de impacto ambiental de infraestructuras lineales de transporte

Abstract

Climate change is currently one of the most important environmental concerns. Numerous human actions contribute to climate change, caused by the emission of greenhouse gases (GHG) and the destruction of sinks. The transport sector is responsible for a quarter of GHG emissions in Spain, 95% of them from roads. Railways are complementary to roads, forming the linear transport infrastructures. Roads and railways are subject to environmental impact assessment (EIA), a process to integrate environmental aspects in decision making. Consideration of climate change in EIA at the international level has only been introduced recently; in Spain it has been very scarce in the last 25 years, especially in roads and railways. Greater awareness and the development of sectoral guides are needed. The contribution to climate change caused by infrastructures require mitigation measures, while the impacts of climate change on infrastructures require adaptation, which can also generate new impacts. These aspects should be considered in EIA. The contribution to climate change is evaluated by the emission of GHGs in construction, operation and maintenance, and the destruction of sinks; other indicators are the ratio of emissions by traveller or freight, or the reduction of emissions due to a modal shift. These indicators should be incorporated into the decision making process. Mitigation of climate change in the transport sector is proposed through large scale objectives, which are outside the scope of EIA, but it is also possible to take actions at this stage. Prevention is possible especially in design, but in operation and maintenance it usually exceeds the scope of EIA. Compensation is possible through carbon sequestration and compensation for destroyed sinks, but this solution is undervalued, despite being viable, and having additional advantages. Its challenges are political will and funding. Climate change has positive or negative impacts on infrastructures. The EIA process should analyze whether the design takes into account these impacts, which are also the basis for adaptation. Adaptation can be applied in many ways, or not implemented at all; the decisions are closely related to functionality and costs. The sectoral approach to adaptation limits the possibility of tackling it globally. The new infrastructures are better adapted, but the existing ones require adaptation, which may be excluded from EIA. Adaptation is considered positive in itself, but may produce undesirable environmental impacts, an aspect that has not being sufficiently considered. It is therefore necessary to assess the adaptation itself within the framework of EIA. This thesis provides the knowledge and tools necessary to deal with the current scarce consideration of climate change in EIA of transport infrastructures, although a greater awareness of the agents involved in this process remain pending.