Getting to knowLife Cycle Emissions

Life Cycle Emissions is one of several terms used in climate, environmental and sustainability management to describe certain aspects of greenhouse gas emissions. The term refers to the total greenhouse gas emissions associated with an individual product, service or process throughout its entire life.

Quantifying life cycle emissions helps provide a complete understanding of greenhouse gases across all phases of a product or service’s life cycle including: raw material extraction and processing, manufacturing, transportation and distribution, operations, maintenance, renewal and end-of-life or repurposing.

Other common terms may be used to describe different aspects of greenhouse gas emissions. Greenhouse gas emissions (GHGs) refer to any compound released to the atmosphere that has the effect of increasing the planet’s retention of heat. This effect is called the global warming potential. Some gases have low emissions rates but high warming effect, and some have high volume of emissions but a relatively low warming effect. GHG emissions are measured in tonnes of carbon dioxide equivalent (tonnes CO2e), which incorporates the amount of emissions multiplied by its global warming potential.

GHGs may be carbon compounds, such as methane, carbon dioxide, and fluorocarbons, or non-carbon based gases, such as nitrogen oxides, sulphur oxides, some non-carbon fluorinated gases, and even water vapour.

Carbon footprint may often be used to describe the total greenhouse gas emissions associated with an individual entity, such as a person or organization, and refers to the total greenhouse gases attributable to all products and services, activities and impacts used by that entity. Net Zero carbon refers to the state where the amount of greenhouse gas emissions is the same as the amount removed from the atmosphere, whether through natural processes or technological ones (referred to as carbon sequestration and storage).

In the same vein, the term carbon negative (less carbon emitted than removed) is sometimes used to indicate a project or goal that exceeds net zero.

Emission Scopes

For calculating and reporting, emissions are usually classified into Scope 1, 2 and 3 emissions, per the IPCC standards.

Scope 1 emissions refer to the direct emissions from sources owned or controlled by an organization.

Scope 2 emissions refer to the indirect emissions from energy produced offsite (normally purchased), such as electricity from the power grid.

Scope 3 emissions are important and often more complicated to measure, as they refer to indirect emissions that occur across the entire value chain of an organization. These emissions include those released upstream, downstream and indirectly from products, services and processes imported from elsewhere to a project or final use. This includes embodied carbon, which is the amount of carbon that is emitted to manufacture an end product.

Upstream Scope 3 emissions result from the production of materials and products (raw materials extraction through to processing, transportation and logistics). Downstream emissions occur from resultant activities within the organization’s value chain, which come from sources like transportation, distribution, processing of waste, use of sold products etc. Emissions in this category include any emissions not in the direct control of the organization. Additional examples include business travel, leased assets, investments and employee commuting.

Emissions and Infrastructure

For infrastructure projects, the specific reporting terms are not necessary, but they may be helpful when considering how decisions around infrastructure will be made. When assessing the Life Cycle Emissions of a particular asset or infrastructure, measuring the greenhouse gas emissions generated through the operation phase of the asset (typically from fossil fuel energy use) is becoming more common and straightforward. By engaging suppliers and service providers, manufacturers, and users, tracking and management of emissions is becoming less onerous, as those managing each phase in the life cycle increase their understanding and the impact of their role in emissions management.

An organization using life cycle emission information can consider sustainable, low carbon material/design alternatives, incentivize manufacturers and suppliers, demonstrate benefits and improvements to engaged stakeholders, drive GHG improvements across the entire value chain, and support organizational goals including target setting, progress, tracking and reporting.

Concrete

As an example, concrete is a common and important material for infrastructure and has amazing properties that allow us to create safe, durable, effective and aesthetic public spaces, buildings, facilities and other assets. That said, the energy required to create cement, the key ingredient in concrete, often requires high temperature processes and produces relatively high levels of GHGs. It is common to refer to the high “embodied carbon” of concrete, which refers to the total greenhouse gas emissions from production, transportation and use of concrete (note: this would be akin to the upstream portion of Scope 3 emissions classification).

The frequency, volume and prevalence of concrete as an essential building material and its characteristic high embodied emissions means that it is an important candidate for more sustainable and climate-friendly alternatives globally. Reducing the life cycle emissions of concrete is an important component of meeting our overall climate and climate targets.

Many organizations are working hard to avoid, use less, reuse, repurpose and reduce concrete and its impact on the climate and the environment. Understanding concrete’s Life Cycle Emissions can help communities and developers make better and more informed decisions on the design of infrastructure, the promotion of more sustainable and lower emissions alternatives, and the industry transition to more sustainable and climate-friendly materials.

As an asset owner or developer, sourcing low carbon concrete, reducing total volume of concrete, recycling concrete and maintaining/extending the life of concrete are some of the important considerations to reduce overall life cycle emissions from this essential and common building material.

To truly meet emissions reduction and net zero targets, a complete understanding of emissions should be considered in all infrastructure decisions. As the concrete example shows, it is important to understand the impact of emissions at all stages in a project’s life cycle. As the majority of infrastructure projects have very long life expectancies, decisions impacting materials, structure, and operations will be difficult and/or expensive to change after they are implemented.