Towards net-zero carbon buildings: tackling uncertainty when predicting the carbon footprint of construction products and whole buildings

为了应对气候变化和生物多样性丧失的严重程度，英国和许多其他国家制定了“净零”温室气体排放目标。快速减少建筑环境至关重要，因为它驱动了全球42%的能源相关二氧化碳排放。为了实现净零碳建筑，我们必须减少以下两个方面：1。运营碳-建筑物的运营使用所造成的排放2。碳排放-由“其他一切”引起的排放，例如材料制造，运输到现场，现场施工，翻新和处置。鉴于世界各地的新建和改造需要大量的建设，在我们继续解决运营碳问题的同时，解决隐含碳问题至关重要。事实上，英国政府的“工业战略：建筑行业协议”旨在到2025年将建筑环境的温室气体排放量减半，并将重点从运营转向全寿命性能。自2019年5月以来，已有超过1,000个建筑和工程实践致力于减少体现和运营碳（统称为全寿命碳; WLC）。英国皇家建筑师协会在其“气候变化报告”中为2030年和2050年设定了WLC目标，而新伦敦计划将要求所有“可行的规划应用”计算和减少WLC。然而，在预测隐含碳（因此也是整个生命周期的碳），从而在实践中将其最小化方面存在着持续的挑战。在单个建筑产品和整个建筑物的水平上，模型通常是确定性的，产生WLC的单点估计。在实践中，设计师和工程师对一种选择比另一种选择低碳的信心有多大还不清楚。在其他科学学科中，概率方法更为常见，在进行比较时使用置信区间和统计显著性检验来产生结果。这种严谨性对于预测建筑物的WLC是必不可少的，以确保低碳设计意图在现实中得到实现。因此，本研究旨在显着改善预测建筑产品和整个建筑物的WLC时的不确定性处理。我们将与低碳建筑供应链上的项目合作伙伴合作，包括产品制造、低碳政策以及结构和建筑设计。在产品层面，我们将改进环境产品声明中不确定性的处理和沟通。在建筑层面，我们将开发和测试一种概率方法，通过设计过程预测整个生命周期的碳排放量。为了实现影响力，我们将参与国际倡议和标准，这些倡议和标准将定义未来的行业实践。

To counter significant levels of climate change and biodiversity loss, the UK and numerous other countries have set targets for "net-zero" greenhouse gas emissions. Rapid reductions in the built environment are crucial, since it drives 42% of global energy-related carbon dioxide emissions. To achieve net-zero carbon buildings, we must reduce both: 1. OPERATIONAL CARBON - the emissions caused by a building's operational use2. EMBODIED CARBON - the emissions caused by 'everything else', such as the manufacturing of materials, transportation to site, onsite construction, refurbishment, and disposal. Given the huge amount of construction required for new build and retrofit around the world, it is critical that embodied carbon is addressed, while we continue to tackle operational carbon.Indeed, the UK Government's 'Industrial Strategy: Construction Sector Deal' aims to halve the greenhouse gas emissions from the built environment by 2025, and to shift focus from operational to whole-life performance. Since May 2019, over 1,000 architecture and engineering practices have committed to reducing both embodied and operational carbon (these are together referred to as whole-life carbon; WLC). The Royal Institute of British Architects has set WLC targets for 2030 and 2050 in its 'Climate Challenge', and the new London Plan will require all 'referable planning applications' to calculate and reduce WLC. However, there are persistent challenges to predicting embodied (and therefore whole-life) carbon, and thus minimising it in practice.In particular, uncertainty is typically ignored. At the levels of individual construction products and whole buildings, models are typically deterministic in nature, producing single-point estimates of WLC. In practice, it is then unclear how confident designers and engineers can be that one option will be lower-carbon than another. In other scientific disciplines, probabilistic approaches are more common, producing results with confidence intervals and using statistical significance tests when making comparisons. Such rigour is now essential for predicting the WLC of buildings, to ensure that low-carbon design intentions are achieved in reality.This research therefore aims to significantly improve the treatment of uncertainty when predicting the WLC of construction products and whole buildings. We will work with project partners across the supply-chain of low-carbon buildings, including product manufacturing, low-carbon policy, and the design of structures and buildings. At product level, we will improve the treatment and communication of uncertainty in Environmental Product Declarations. At building level, we will develop and test a probabilistic approach for predicting whole life carbon through the design process. To achieve impact, we will engage international initiatives and standards that will define industry practice into the future.