Environmental Sustainability Glossary

This glossary aims to define the wording used within our Technical Advisory Group (TAG) for environmental sustainability. It doesn’t claim to be holistically complete and therefore provides additional resources where needed.

This glossary is also a living artifact that changes and is edited over time.


Carbon or Carbon Dioxide (CO2)

Carbon Dioxide commonly just named carbon is a colorless, odorless gas, that is released from burning fossil fuels, such as coal, oil, and natural gas. CO2 emissions are fundamentally a natural process, but one that has been exacerbated by the burning of natural resources for energy production or logistics to such an extent that it is now a major factor in climate change. Depending on how the supply chain of hardware (e.g. computer chips, cables etc.) and software (e.g. digital services like cloud computing, file sharing etc.) production/services is structured, CO2 gets emitted.

Carbon Diet

Actions to reduce the output of CO2 to reduce the impact on the environment.

Carbon Footprint

Is the total amount of greenhouse gasses, often carbon dioxide, that a person, family, company, organization, or building (like a data center) releases to the environment. This includes the release of GHG through direct use (e.g. the energy consumption of a data center) and indirect use (e.g. the energy required to produce servers).

Climate or Carbon Neutrality

Often used by organizations and companies to express that they equalize the cause of carbon pollution they generate. This typically happens by buying negative carbon emissions from organizations that really saved carbon or are net-zero or even reduce more carbon than they produce. However, it is important to understand that this is only a compensation and does not have to imply a new product development leading to more sustainability. Please also read about the term “Net Zero” as both terms are often mixed or misleadingly used.



Goods and services that use fewer resources and create less waste and pollution.

Embodied (Carbon) Emissions

Embodied (sometimes substituted with the word Embedded) Carbon Emissions are all emissions caused during a good’s production. That can include anything from transportation, storage, heating, the production of other goods to finish this good and so on.


This is an umbrella term that usually is used to refer to gasses, but can also include other factors such as micro-particles. Emissions are categorized into three scopes: Scope 1: direct emissions: for example the CO2 output of the vehicles owned by the company Scope 2: indirect emissions: for example the power consumption of a data center, that causes emissions by the production of electricity Scope 3: indirect emissions, that not directly can be changed: for example delivery chain caused CO2 pollution

Environmental Sustainability

Sustainability is the concept of a social, economical and environmental activity that, in simple terms, leaves the ecosystem as it found it. Environmental sustainability focuses on the ecological impact of our doings and how we can improve our actions to reduce or eliminate our negative impact on nature, earth, and finally humanity.


Green House Gas (GHG)

Any kind of gasses caused by nature or human activities that trap heat in the atmosphere. GHG includes carbon dioxide, methane, ozone and others. These gasses are called greenhouse gas because they have the same effect as a greenhouse: the sunlight can enter the house and part is reflected back, but it can‘t leave the greenhouse fully because the roof prevents the heat from escaping. This causes the inside of a greenhouse to get hotter and hotter, the same as what is going on with the earth. See also: Emissions.


Net Zero

This phrase stands for zero-carbon emissions, in that anyone (including companies) using this term must store or neutralize the same amount of carbon as that consumed.


Operational Carbon Emission

This refers to the quantity of carbon emitted during the phase where something is in use. Typical examples are when buildings like data centers are in use, or (if measurable) this may also refer to smaller elements in that datacenter, such as when a server is powered on. Per definition, operational carbon emissions include the usage, management and maintenance.


Power Usage Effectiveness (PUE)

The PUE describes how efficiently a data center uses energy. It defines how much energy is used by the computing equipment vs the overall power consumption of the data center. An ideal PUE is 1.0. It is also a global standard under the ISO/IEC 30134-2:2016.

PUE is calculated either through: Total Facility Energy / IT Equipment Energy 1 + Non-IT Facility Energy / IT Equipment Energy


Server Idle Energy Coefficiency (SIEC)

Developed by the research project LEAP and is done by measuring the server energy consumption. What is relevant here is the continuous energy consumption of the server VS. the actually required energy by the chip. This mainly depends on the configuration or modus of the server power management. Very simplified, it’s the SIEC calculated by the energy wasted during idle time decided by the energy consumption in total. The higher the number (given as %) the worse it is.


GHG - Green House Gas

PUE - Power Usage Effectiveness

SIEC - Server Idle Energy Coefficiency

Additional Resources