Tackling Scope 3 Emissions In the Construction Sector Using Hybrid Lifecycle Assessment.

许多行业的公司都在努力估计和减少他们的碳足迹。这对于满足英国的立法碳预算和实现全球气候变化巴黎协定至关重要。建筑业是受到关注和变革的行业之一，因为建筑物和基础设施的碳足迹占全球温室气体排放量的42%[1]。在公司层面，碳足迹通常分为范围1，范围2和范围3排放。范围1和2涉及公司的能源使用，这相对容易衡量。范围3是“其他一切”，包括公司供应链上游产生的所有排放。范围3排放量众所周知难以估计，但可以主导公司的碳足迹，包括建筑业。估算范围3供应链排放量的方法主要有两种：“自上而下”（基于经济投入产出表）或“自下而上”（基于制造或运输等单个流程的工程和排放数据）。自上而下的方法更全面，但它们是整个部门的广泛平均值，不一定代表特定的公司或产品。自下而上的方法提供了更好的具体性，但存在不完整或数据可用性差的问题。混合生命周期评估（LCA）试图通过结合两种方法来充分利用每种方法。然而，虽然混合方法有很长的历史，但它们尚未被广泛使用，并且在英国建筑中根本没有使用。因此，该博士将为英国建筑业开发一种混合LCA方法。这将产生新的学术研究，具有在建筑行业内外广泛应用的潜力。全球建筑和建设联盟，《2019年全球现状报告：迈向零排放、高效和弹性建筑和建筑行业》。

Companies in many sectors are trying to estimate and reduce their carbon footprint. This is essential for meeting the UK's legislative carbon budgets, and for achieving the global Paris Agreement on climate change. Construction is one of the sectors that is receiving attention and change, because the carbon footprint of buildings and infrastructure represents 42% of global greenhouse gas emissions [1]. At a company level, carbon footprints are usually broken down into Scope 1, Scope 2 and Scope 3 emissions. Scope 1 and 2 relate to the energy use by the company, which is relatively easy to measure. Scope 3 is 'everything else', including all the emissions caused upstream in a company's supply chain.Scope 3 emissions are notoriously difficult to estimate but can dominate a company's carbon footprint, including in construction. There are two main approaches for estimating Scope 3 supply chain emissions: "top-down" (based on economic input-output tables) or "bottom-up" (based on engineering and emissions data for individual processes, such as manufacturing or transport). Top-down approaches are more complete, but they are broad averages for whole sectors and they are not necessarily representative of specific companies or products. Bottom-up approaches provide much better specificity but suffer from incompleteness or poor data availability. A hybrid life cycle assessment (LCA) seeks to make the most of each approach by combining the two. However, while there is a long history of hybrid methods, they have not yet been widely used, and are not used at all in UK construction. This PhD will therefore develop a hybrid LCA method for the UK construction sector. This will produce novel academic research with potential for significant use within the construction sector and beyond. References[1] Global Alliance for Buildings and Construction, Global Status Report, 2019: Towards a zero-emission, efficient and resilient buildings and construction sector.