The Alphabet Soup of Sustainability

It can be hard, even for seasoned Sustainability professionals, to keep with the growing number of terms and concepts in the field.  This glossary provides the definitions of the most commonly used ones.  It is designed as a quick reference for ESG and Sustainability professionals.

• 2°C  scenario: Under the 2015 Paris Agreement, nearly 200 countries agreed to limit global warming to no more than 2 degrees Celsius by 2100, and to aim for a no more than 1.5 degrees Celsius increase. The 2-degree scenario is widely seen as the global community’s accepted limitation of temperature growth to avoid significant and potentially catastrophic changes to the planet.
  
  
• Absolute Target: A target to reduce Greenhouse Gas emissions by a fixed amount.  For example, reduce GHG emissions by 50% of 2020 levels by 2030. These are in contrast to Intensity Targets that are relative to other factors such as a company's revenue or number of employees.  
  
  
• Adaptation: Changes a company makes in response to effects of climate change to reduce the adverse impacts to its business and the environment. 
  
  
• Best available technology (BAT): The best available technology or best available techniques is the technology approved by legislators or regulators for meeting output standards for a particular process, such as pollution abatement. BAT is a moving target on practices, since developing societal values and advancing techniques may change what is currently regarded as "reasonably achievable", "best practicable" and "best available".
  
  
• Bioenergy: Bioenergy is renewable energy derived from biological sources, to be used for heat, electricity, or vehicle fuel. It is generated using waste that would otherwise go to landfills.
  
  
• Biodiversity: Biodiversity or biological diversity is the variety and variability of life on Earth. Biodiversity is not distributed evenly on Earth, it is usually greater in the tropics as a result of the warm climate and high primary productivity in the region near the equator. These tropical forest ecosystems cover less than 10% of earth's surface and contain about 90% of the world's species.
  
  
• Biogas: Biogas is a type of biofuel naturally produced from the decomposition of organic waste. When organic matter, such as food scraps and animal waste, breaks down in an anaerobic environment (without oxygen), it releases a blend of gases, primarily methane and carbon dioxide. Due to the high methane content (typically 50-75%), biogas is flammable and therefore produces a deep blue flame and can be used as an energy source.
  
  
• Biogenic Carbon Emissions: Biogenic carbon emissions are those that originate from biological sources such as plants, trees, and soil. Biogenic carbon is absorbed and stored by the flora as a natural consequence of its life cycle. Through the process of photosynthesis, carbon is taken from the air and distributed among the leaves, stems and roots of plants. When plants die, the carbon is slowly released from its decomposing remains, or else emitted when the organic matter is combusted as biomass. By contrast, non-biogenic carbon has not been absorbed by living matter. Most commonly, the term is used to refer to carbon stored in fossil fuels in the form of coal, oil, and gas. Biogenic carbon is mostly regarded as preferable to non-biogenic carbon, because it can be replenished more readily, for example, through planting of new trees. Non-biogenic carbon releases a significant amount of carbon in a short space of time. Since it takes millennia or more to form fossil fuels, combusting them and releasing their stored carbon in a matter of hours, days or weeks is unsustainable from an environmental perspective.
  
  
• Biomass Energy: Biomass energy is energy generated or produced by living or once-living organisms. The most common biomass materials used for energy are plants, wood, and waste. The energy from these can be burned to create heat or converted into electricity.  Also see Bioenergy and Biogas.
  
  
  
• Carbon Capture and Storage (CCS): Carbon capture and storage (CCS) or carbon capture and sequestration is the process of capturing carbon dioxide (CO₂) before it enters the atmosphere, transporting it, and storing it (carbon sequestration) for centuries or millennia.
  
  

• Carbon Offset: A Carbon Offset is a reduction or removal of emissions of carbon dioxide or other greenhouse gases made in order to compensate for emissions made elsewhere. Offsets are measured in tonnes of carbon dioxide-equivalent (CO₂e). One ton of carbon offset represents the reduction or removal of one ton of carbon dioxide or its equivalent in other greenhouse gases. Additionality is essential for the quality of carbon offset credits. GHG reductions are additional if they would not have occurred in the absence of a market for offset credits. If the reductions would have happened anyway – i.e., without any prospect for project owners to sell carbon offset credits – then they are not additional.  – if their associated GHG reductions are not additional, then purchasing offset credits in lieu of reducing your own emissions will make climate change worse.

• Carbon Offset Credit: A carbon offset credit is a transferrable instrument certified by governments or independent certification bodies to represent an emission reduction of one metric tonne of CO₂, or an equivalent amount of other GHGs . The purchaser of an offset credit can “retire” it to claim the underlying reduction towards their own GHG reduction goals.  Additionality is essential for the quality of carbon offset credits. GHG reductions are additional if they would not have occurred in the absence of a market for offset credits. If the reductions would have happened anyway – i.e., without any prospect for project owners to sell carbon offset credits – they are not additional.  If GHG reductions are not additional, then purchasing offset credits in lieu of reducing emissions makes climate change worse.

• Circular economy: A carbon offset credit is a transferrable instrument certified by governments or independent certification bodies to represent an emission reduction of one metric tonn
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