The Absolute Environmental Sustainability Assessment (AESA) framework is an emerging field in environmental research that aims at comparing the estimated environmental burden generated by a system on its life cycle to the carrying capacity that can be assigned to this system, i.e. the amount of impacts that it can cause without causing unacceptable impairment of ecosystem functional integrity. This paper aims to expand the AESA framework to multifunctional systems. We applied it to a simplified case study based on municipal solid waste (MSW) management, since such a system provides several functions such as reduction of the quantity and toxicity of waste, production of heat, electricity or secondary materials. Thus, we could identify the specific questions that arise from this multifunctionality in the context of AESA.

Based on the theory of AESA, we developed a four-steps methodology to identify the most significant impacts at both system and global scales. That methodology consisted of (step 1) quantifying the impacts of the studied system with conventional Life Cycle Assessment (LCA) followed by a normalisation step; (step 2) quantifying the number of beneficiaries from this system; (step 3) identifying impact categories for which the studied system causes significant impacts and global carrying capacities are exceeded; and (step 4) quantifying the Assigned Carrying Capacity (ACC) of the system, based on a utilitarian perspective and its contribution to the satisfaction of human needs.

We then applied this methodology to a simplified model of the MSW management implemented in the Lyon Metropolitan Area (France), as a proof of concept. Steps 1 to 3 helped elaborate a hierarchy of impact categories, highlighting which ones should be reduced in priority. Step 4 required significant knowledge about how the functions of the studied system were used, both directly and indirectly, to satisfy human needs. We used national Supply and Use Tables and several simplifying hypotheses to that end. We also tested different sharing principles based on macroeconomic indicators. This variety of sharing principles helped refine the hierarchy developed in Step 3 by identifying which carrying capacities were most certainly exceeded by the studied system.

绝对环境可持续性评估 (AESA) 框架是环境研究中的一个新兴领域，旨在将系统在其生命周期中产生的估计环境负担与可以分配给该系统的承载能力进行比较，即在不对生态系统功能完整性造成不可接受的损害的情况下，它可以造成的影响量。本文旨在将 AESA 框架扩展到多功能系统。我们将其应用于基于城市固体废物 (MSW) 管理的简化案例研究，因为这样的系统提供了多种功能，例如减少废物的数量和毒性、产生热量、电力或二次材料。因此，我们可以在 AESA 的背景下确定这种多功能性产生的具体问题。

基于 AESA 理论，我们开发了一个四步法来确定系统和全球范围内最显着的影响。该方法包括（步骤 1）使用常规生命周期评估 (LCA) 量化研究系统的影响，然后是标准化步骤；（步骤 2）量化该系统的受益人数量；（第 3 步）确定研究系统对其造成重大影响和超过全球承载能力的影响类别；（步骤 4）基于功利主义的观点及其对满足人类需求的贡献，量化系统的分配承载能力（ACC）。

然后，我们将此方法应用于在里昂大都市区（法国）实施的 MSW 管理的简化模型，作为概念证明。步骤 1 到 3 有助于详细说明影响类别的层次结构，突出显示应优先降低哪些类别。第 4 步需要关于如何直接和间接使用所研究系统的功能来满足人类需求的重要知识。为此，我们使用了国家供应和使用表以及几个简化的假设。我们还根据宏观经济指标测试了不同的共享原则。通过确定所研究的系统最肯定超过了哪些承载能力，这种多种共享原则有助于完善步骤 3 中开发的层次结构。