Environmental Sustainability Terminology and Concepts

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Table of Contents

2. Definition of Terms

Given that the term 'considerations' is well known within the IETF community, it is fair to start by defining 'sustainability'. The 1983 UN Commission on Environment and Development had important influence on the current use of the term. The commission's 1987 report [UNGA42] defines it as development that "meets the needs of the present without compromising the ability of future generations to meet their own needs". This in turn involves balancing economic, social, and environmental factors.¶

This section defines sustainability-specific terms as they are used in the document, and as they pertain to environmental impacts. The goal is to provide a common sustainability considerations lexicon for network equipment vendors, operators, designers, and architects.¶

Notwithstanding the most comprehensive set of definitions of relevant terms readers can find at [IPCC], this section contributes the application and exemplification of the terminology to the internetworking domain and field. The terms are alphabetically organized.¶

Appropriate technology:

Appropriate technology is a movement (and its manifestations) encompassing technological choice and application that is small-scale, affordable by locals, decentralized, labor intensive, energy efficient, environmentally sustainable, and locally autonomous. Though the original name for the concept now known as appropriate technology, "intermediate technology" is now often considered a subset of appropriate technology that focuses on technology that is more productive than "inefficient" traditional technologies, but less costly than the technology of industrialized societies. Globally impactful technology is to be adaptable to local contexts it is used in. Regarding internetworking, there could be linkages to centralization / decentralization challenges, as well as maintainability & deployability aspects. Considering the diversity of local contexts, from developed countries with remote/rural coverage/access issues, to developing countries with unstable electricity grids as well as literacy and technology usability/accessibility issues, internetworking technology needs to be designed, developed and operated according to these local requirements, also supporting small scale business models to make impact.¶

Biodiversity loss:

Biological diversity is a measure of the abundance and variety of life on earth. Biodiversity loss is the depletion of this diversity due to human activity, notably through the destruction of natural ecosystems and through the cascading effects of climate change, materials extraction, waste disposal and pollution, among other impacts, on the living world and species.¶

CO2e / CO2eq / CO2-eq:

Carbon dioxide equivalent, is the unit for measuring the climate change impact of non-CO2 gases as compared to CO2, which is selected as a benchmark.¶

Carbon awareness:

is being mindful of the carbon intensity of the electricity being used and prioritizing the use of low carbon intensity electricity in network set-up and operations. As carbon intensity is location and time dependent, carbon awareness requires dynamic monitoring and response, such as carbon aware routing and networking. This is a form of "demand shaping" which aims to match the use of energy with the supply of clean energy.¶

Carbon intensity (CI):

also referred to as emission intensity and emission factor, is a measure of the carbon-equivalent emission of consumed electricity, i.e., grams of carbon-equivalent per kilowatt hour (gCO2e/KWh). When the supplied energy mix is purely from renewable sources such as sun and wind, carbon intensity is practically 0, when coal and gas-powered electricity generation gets in the mix, carbon intensity increases. Carbon intensity could change instantaneously or predictably based on the time and location of electricity use. Prioritizing electricity use when carbon intensity is low is a target.¶

Carbon offset and credit:

is a reduction of GHGs from the atmosphere as compensation for GHGs produced elsewhere and the credit generated and used respectively. This reduction in GHG emissions can be an increase in carbon storage through land restauration, or an actual removal of GHG. For example, certified forestation projects that absorb carbon dioxide produce carbon credits that an airline can use to offset its GHG emissions by using (purchasing) these credits. There are accredited carbon trading mechanisms to facilitate this exchange. This is generally regarded as a non-scalable solution, and activities such as the reduction of GHG emissions and the shifting of electrical energy production to renewables are a primary focus.¶

Circularity (circular economy):

is a model or system where material resources and products are kept in use for as long as possible through long life cycles, reuse, repair, refurbishing and recycling, thereby reducing materials use, waste, and pollution as well as biodiversity and geodiversity loss. Keeping internetworking equipment in longer use through modularity, serviceability, upgradeability, maintainability are strategies to improve circularity.¶

Climate change (climate emergency, global warming):

can be summarized as the increase in the global average temperatures and its destructive impact on life on Earth. The climate emergency refers to the ongoing and projected impacts of rising global temperatures and the narrow time window we have to limit temperature increases to a threshold determined by the Paris Climate Agreement (2015) to avoid the permanent destabilization of Earth life-support systems.¶

Climate change adaptation:

are the measures we can take to adjust ourselves to the already happening and projected future adverse effects of climate change. This notably includes raising the resilience of internetworking solutions to higher operating temperatures and other impacts of climate change, as well as the use of internetworking technology to increase the resilience of societies and nature itself.¶

Climate change mitigation:

encompasses all measures to reduce the impact of climate change. More specifically, any measures that reduce the amount of GHGs in the atmosphere can be considered as climate change mitigation through reduced inflow of GHGs into the atmosphere (such as burning of fossil fuels) or increasing the impact of carbon sinks such as forests and oceans. Reducing the carbon footprint of internetworking and increasing its carbon handprint by helping other sectors to decarbonize are mitigation efforts.¶

CUE:

Carbon usage effectiveness [CUE] is a metric that helps determine the amount of greenhouse gas (GHG) emissions produced per unit of IT energy consumed within a data center. It provides an effective way to measure operational carbon footprint and thus the environmental impact of data center operations. The CUE is the ratio of the total CO2 emissions caused by total data center energy consumption, divided by the energy consumption of IT equipment. To calculate CUE when using electricity from the grid, carbon emissions can be based on published data. See also "PUE".¶

Doughnut economics:

is a visual framework for sustainable development. It attempts to find a safe operational space within planetary boundaries and complementary (yet seemingly opposing) social boundaries, thereby meeting the needs of human societies without pushing earth environmental boundaries to their tipping points [Doughnut]. The significance of this model for interworking is that it demonstrates how to conceptualize and position boundaries in our designs that are seemingly opposing, to create a balanced approach, for example between energy efficiency and performance or resiliency and materials efficiency. It is not one or the other, but to find a space where both can be achieved without crossing boundaries in respective domains.¶

Embodied emissions:

also referred to as embodied carbon and embedded carbon, refers to the amount of GHG emissions associated with upstream phases - raw material extraction, production, transportation (of materials and of product), and manufacturing-stages of a product's lifecycle. Some initiatives also consider disposal.¶

Energy, power, and their measurement:

In physics, energy is defined as the capacity or ability to do work. For a system to provide an output, the quantitative property of energy is transferred to it. The energy measurement unit in the International System of Units (SI) is the joule (J). Power is energy used per second, measured in the International System of Units in watts (W), equivalent to the rate of one joule per second (J/s). In other words, energy is the integration of power over time. As such, Kilowatt-hour (kWh) is also a measure of energy, equivalent to 1 kW of power maintained for 1 hour, which is equal to 3.6 MJ (million joules).¶

Energy efficiency (EE):

increased energy efficiency can be summarized as doing the same task with less energy use, that is, providing a useful output/impact with as little energy as possible, eliminating energy waste. Switching to more efficient power supplies and silicon or developing more efficient transmission or signal processing algorithms improves EE. Developing energy efficiency metrics for internetworking and associated measurement methodologies and conditions as well as consistently collecting this data over time are essential to demonstrating EE improvements. An example of a common outcome-oriented metric is energy consumption per data volume or traffic unit, in Wh/B [Telefonica]; this particular metric has however also been criticized for being easy to misinterpret, falsely indicating that systems are energy proportional even when they are not (see "Energy proportionality".)¶

Energy equity:

Energy equity aims to minimize the negative impacts of energy systems and maximize the benefits for all energy users. Historically, these impacts and benefits haven't been equitably distributed. Energy equity recognizes that disadvantaged communities have been historically marginalized and overburdened by pollution, underinvestment in clean energy infrastructure, and lack of access to energy efficient housing and transportation.¶

Energy proportionality:

is the correlation between energy used and the associated useful output. For internetworking this is generally interpreted as the proportionality of traffic or traffic throughput and energy used. This concept is broadly applicable to networking infrastructure, data center, and other communication architectures. It is not a given that there is a one-to-one correlation between traffic and energy use, notably due to the materially significant idle power use by devices, as well as the overall network capacity being allocated to serve at times of highest traffic utilization.¶

Energy savings / conservation (ES):

is the avoidance of energy use, by eliminating a task altogether, when possible. Shutting down unused ports on a networking equipment is energy savings/conservation.¶

Footprint (environmental/ecological):

in general terms is the impact we have on the planet. It can be divided into subcategories as carbon footprint, water footprint, land footprint, biodiversity footprint, etc. Related to the climate emergency, we are mostly focused on our carbon footprint, however, it has been shown that sub-categories of footprint are not entirely independent of each other. For example, our carbon footprint has a proven impact on the climate emergency through rising global temperatures, cascading significant impact on forest cover in warming areas since tree species adapted to certain climates vanish, thereby reducing biodiversity in that region, in-return impacting the carbon sink properties of the environment and exacerbating climate change. A holistic approach to our environmental footprint would therefore provide the best opportunity to create impact.¶

GHGs:

Greenhouse gases are types of gases that trap heat from the sun in earth's atmosphere, thereby increasing average global temperatures and creating the climate emergency. Carbon dioxide (CO2) is one of the most common (and referenced) greenhouse gases. There are others such as methane (CH4 - a much more potent GHG than CO2) and sulfur hexafluoride (SF6 - an artificial electrical insulator with tens of thousands of times more warming effect than CO2).¶

GHG Emissions Scopes:

According to the Greenhouse Gas (GHG) Protocol [GHG-Proto], Chapter 4, the emissions scopes are defined as below:¶

• Direct GHG emissions are emissions from sources that are owned or controlled by the company.¶

• Indirect GHG emissions are emissions that are a consequence of the activities of the company but occur at sources owned or controlled by another company.¶

The GHG protocol [GHG-Proto], Chapter 4, also includes the following descriptions of emissions scopes for accounting and reporting purposes:¶

• Scope 1 Emissions: Direct GHG emissions - Direct GHG emissions occur from sources that are owned or controlled by the company, for example, emissions from combustion in owned or controlled boilers, furnaces, vehicles, etc.; emissions from chemical production in owned or controlled process equipment.¶

• Scope 2 Emissions: Electricity indirect GHG emissions - Scope 2 accounts for GHG emissions from the generation of purchased electricity consumed by the company. Purchased electricity is defined as electricity that is purchased or otherwise brought into the organizational boundary of the company. Scope 2 emissions physically occur at the facility where electricity is generated.¶

• Companies shall separately account for and report on scopes 1 and 2 at a minimum.¶

• Scope 3 Emissions: Other indirect GHG emissions - Scope 3 is an optional reporting category that allows for the treatment of all other indirect emissions. Scope 3 emissions are a consequence of the activities of the company, but occur from sources not owned or controlled by the company. Some examples of scope 3 activities are extraction and production of purchased materials; transportation of purchased fuels; and use of sold products and services.¶

In telecommunications networks, Scope 3 emissions include the use phase of the sold products in operations, and is currently the largest part by far, of the whole GHG emissions (Scopes 1, 2 and 3), depending on the carbon intensity of the energy supply in use.¶

GWP:

Global warming potential, is the potential impact of GHGs on climate change, measured in CO2e.¶

Geodiversity:

is the variety of the nonliving parts of nature, that is, the materials constituting Earth, including soils, water (rivers, lakes, oceans), minerals, landforms and the associated processes that form and change them. The materials used in the production of internetworking equipment as well as their manufacturing and operational processes themselves, have impact (footprint) on geodiversity. Materials efficiency as well as circularity improvements help mitigate this impact.¶

Handprint (environmental/ecological):

is a concept developed in contrast to footprint, to quantify and demonstrate the positive environmental/ecological impact of technologies, products or organizations. Through a LCA (life cycle assessment) approach, the use of a technology or the products and services of an organization would have both a footprint and handprint usually denoted by the terms "X for sustainability" (handprint) and "Sustainable X" (footprint). What is important is that handprint impact does not compensate for footprint impact. They are to be calculated and reported independently; footprint to be minimized as much as possible, and handprint maximized as much as possible, which are by definition different activities anyway. Otherwise, this might be construed as "greenwashing". A popular seesaw figure in common sustainability literature depicting handprint and footprint sitting on opposite ends of a seesaw, one going up while the other is going down is a misguided representation.¶

LCA (Life Cycle Assessment):

is a comprehensive methodology to measure the environmental impact of a product, service, or process over its complete lifecycle, from the extraction and procurement of materials, through design, manufacturing, distribution, deployment, operations (use), maintenance/repair, decommissioning, refurbishment/reuse, recycling and disposal (waste), considering the full upstream and downstream supply chains as well. It is an extremely complicated process and there are multiple methods used worldwide, which might not produce same/similar results. LCA covers full footprint aspects, not only covering carbon, but also materials and biodiversity. Many of the subtleties and nuances of the measurement of GHG and environmental impacts stem from the very important distinction between attributional and consequential models. Detailed definitions can be found at [UNEP-LCA].¶

LCA - Attributional Model:

Also referred to as Allocational models, start by allocating or attributing quantities (e.g., GHG emissions) to entities (e.g., a router, a building, a town), and performing comparisons between the measurements (or estimates) of the quantity by the entities.¶

LCA - Consequential Model:

Perform the measurement of the quantity by establishing a baseline scenario (e.g., before feature introduction) and a modified scenario (e.g., after the feature introduction).¶

Materials efficiency and reuse:

is the concept of using less primary and (more) recycled materials to provide the same output. A networking equipment that provides the same function with less aluminium used is more materials efficient. Reuse of materials in manufacturing, thereby reducing primary materials extraction is a cornerstone of circularity, reducing environmental footprint and promoting geodiversity.¶

Net-zero:

in general, is to bring down GHGs as close to zero as possible. It is generally recognized that it may not be possible to get GHGs to 0 in many contexts and the balance is said to be covered by carbon offset. For example, many organizations and countries have net-zero targets by certain dates and typically what they mean is that they will reduce their GHGs by more than 90% and the remaining up to 10% will be offset.¶

PUE:

Power usage effectiveness, is a data centre energy efficiency metric. The PUE is defined by dividing the total amount of power entering a data center by the power used solely to run the IT equipment within it. PUE is expressed as a ratio, with the overall power usage effectiveneess improving as the quotient decreases towards one. See also "CUE".¶

Planetary boundaries:

is a concept that defines 9 environmental boundaries that, if not crossed, provides a safe space for humanity to live. This was developed and tracked by the Stockholm Resilience Centre [Planet-B]. Their latest report indicates that 6 out of the 9 boundaries have already been crossed. This translates to the increased risk of irreversible environmental change, the so-called tipping points. Climate change is one of these boundaries, represented as carbon dioxide concentration in the atmosphere (ppm by volume) and others are biodiversity loss, land use, fresh water, ocean acidification, chemical pollution, ozone depletion (one boundary that has been successfully mitigated), atmospheric aerosols and biogeochemical (nitrogen in the atmosphere and phosphorus in oceans).¶

Rebound effect:

is the reduction in the potential benefits of more efficient technologies and solutions to reduce resource use, due to the increased demand they might trigger as costs might decrease, in return even increasing the overall resource use. This is known as Jevons paradox: efficiency leading to increased demand. In internetworking, this can manifest itself when more energy and resource efficient systems reduce the cost for infrastructure build and operations and when this is reflected to customers as reduced cost, customers respond by increased use of telecommunications services which pushes infrastructure build and operations upwards, thereby negating the projected gains from efficiency measures. Another descriptive source for this phenomenon can be found at [Frontiers].¶

Tipping points:

are critical environmental thresholds, which when crossed likely lead to irreversible state changes in climate systems that might push the overall earth system out of its stable state that supports life on Earth. For example, there are tipping points defined for the Antarctic and Greenland ice sheets disappearing, the Arctic sea-ice loss, Siberian permafrost loss or the dieback of the Amazon and Boreal forests. As planetary boundaries are crossed, the likelihood of the tipping points being reached also increases. When the tipping points are hit, notably simultaneously, the overall impact to the global Earth system might be catastrophic, as another stable state which no longer supports life could be reached.¶

UN SDGs:

United Nations Sustainable Development Goals are 17 global objectives that collectively define a framework for a sustainable global system where people and the planet collectively thrive and live in peace, prosperity and equity. They were adopted in 2015 and most of them have a target achievement date of 2030 [UN-SDG]. They are part of the so-called UN 2030 Agenda. The International Telecommunications Union (ITU) has published on how our technology could help meet the UN SDGs [ITU-ICT-SDG]. Notably, most UN SDGs provide guidance for the handprint impact of internetworking technologies, while some are also related to potential action for footprint reduction. The 17 SDGs are:¶

Goal 1

No poverty¶

Goal 2

Zero hunger¶

Goal 3

Good health and well-being¶

Goal 4

Quality education¶

Goal 5

Gender equality¶

Goal 6

Clean water and sanitation¶

Goal 7

Affordable and clean energy¶

Goal 8

Decent work and economic growth¶

Goal 9

Industry, innovation and infrastructure¶

Goal 10

Reduced inequalities¶

Goal 11

Sustainable cities and communities¶

Goal 12

Responsible consumption and production¶

Goal 13

Climate action¶

Goal 14

Life below water¶

Goal 15

Life on land¶

Goal 16

Peace, justice and strong institutions¶

Goal 17

Partnerships for the Goals¶

The SDG Academy [SDG-Acad] also provides useful information on the topic, as well as progress to date.¶

3. Environmental Sustainability Concepts

Authors' Addresses