u3a

Climate Change & Environment

JargonBuster

Terms explained; jargon busted; acronyms expanded. You will be none the wiser, but may at least be better informed. For more on searching, see Scrapbook Pages.

Note on acronyms: the Guardian convention for acronyms that can be pronounced as words (BECCS, NATO) is to write them in mixed case (Beccs, Nato). I don't do that here. One exception is Defra, which seems to be mixed case everywhere.

Please send feedback on this page to Subject Adviser - did you find it useful, or not useful?

A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z

Click on any section heading (A, B, C etc) to return to this index.

A

AD Anaerobic Digester; see Where the Food Waste Goes.

AED Atmospheric Evaporative Demand, aka “atmospheric thirst”: the water that the atmosphere demands from the land. Research suggests that the atmosphere is demanding more water and droughts are getting more severe even where rainfall hasn’t significantly declined.

Anticyclonic gloom see dunkelflaute.

ARn Allocation Round n. An AR is an auction whereby DESNZ offers Contracts for Difference to generators of low-carbon electricity..

ASHP Air Source Heat Pump.

Aspirational Recycling see wishcycling.

B

BECCS Bio-Energy with Carbon Capture and Storage.

BESS Battery Energy Storage System.

Blue hydrogen like grey hydrogen it is made by steam methane reforming using natural gas, but the CO2 is captured and does not enter the atmosphere. There are only a few industrial-scale plants, but blue H2 features in UK and US government plans to get to net zero.

C

Carbon footprint "the total amount of greenhouse gases emitted by something - a lifestyle, a supply chain, an organisation, or an activity. Everything from a banana to a ship has a carbon footprint"; this definition from a useful intro in The Conversation.

CAT The Centre for Alternative Technology (in Welsh, Canolfan y Dechnoleg Amgen). CAT is a charity devoted to environmental education and innovation. It is based near Machynlleth on Powys. See also Zero Carbon Britain.

CCC Climate Change Committee. The CCC is an independent, statutory body established under the Climate Change Act 2008. It advises the UK and devolved governments on emissions targets and reports to Parliament on progress made in reducing GHG emissions and preparing for and adapting to the impacts of climate change. The CCC's Sixth Carbon Budget advises ministers on the volume of GHGs the UK can emit in the years 2033-2037. It is a big document which is summarised very briefly in Second Nature 018. The Seventh Carbon Budget has now been issued, together with a Supplementary Analysis published in March 2026.

Carbon Brief reports a paper in the journal Climate Policy which analyses government responses to CCC recommendations. Of 592 recommendations in the period 2009–2020 23% were accepted in part, but only 2% were accepted in full.

CCS Carbon Capture and Storage; see also BECCS.

CDR Carbon Dioxide Removal: activities that remove CO2 from the atmosphere and durably store it in geological, terrestrial, or ocean reservoirs, or in products. Existing and potential CDR measures include afforestation and reforestation, land restoration and soil carbon sequestration, BECCS, direct air carbon capture and storage (DACCS), enhanced weathering and ocean alkalinisation.

CfD Contract for Difference, a financial instrument in which a buyer and a seller agree on a strike price and the buyer pays the seller the difference between the current wholesale price and the clearing price. In the electricity market generators get the wholesale price from NESO and if it is below the clearing price then they get a top-up from LCCC, and if it is above the clearing price then they pay back. The mechanism is designed to de-risk generation and bring private capital into the electricity market. There is more on CfDs in Second Nature 004.

Circular Economy a model of production and consumption: sharing, leasing, reusing, repairing, refurbishing and recycling existing materials and products as long as possible so that the life cycle of products is extended. There is a presentation available on this.

Clean Energy 2030 a report from NESO to its single shareholder, Ed Miliband, subtitled "Advice on achieving clean power for Great Britain by 2030". It is discussed in Second Nature 026.

Climate Forcing see Radiative Forcing.

A Climate Trap has been defined as 'a vicious cycle where short-term survival decisions deepen long-term climate viability'.

Compostable materials are materials that have been certified to break down completely into non-toxic components (water, carbon dioxide, and biomass) that will not harm the environment, given the right conditions. Not all compostable materials are suitable for composting at home. Bioplastics (compostable alternatives to conventional plastic packaging) are plant-derived but they require higher levels of heat, water, oxygen and micro-organisms than a home compost can to fully break down. For a thing to be legally labelled compostable, it has to have been certified to break down in industrial (council) composting facilities within 180 days. 'Compostable' bioplastics should not be recycled as this can contaminate other plastics. See also EN 13432.

COP Conference of the Parties to the 1992 United Nations Framework Convention on Climate Change (UNFCCC). The Conference is held annually (COP29 in 2024). There is a separate series of COPs on biodiversity, with COP16 being in 2024.

CTBO Carbon Takeback Obligation, a measure which would require that all fossil fuels extracted or imported are offset by storing underground an amount of CO2 equivalent to that generated by that fuel. A CTBO, phased in, would reach the requirement of storing 100% of emissions by 2050. Unlike a carbon tax, which simply makes polluting more expensive, CBTO ensures carbon clean-up and makes the cost a part of the cost of fossil fuel production.

D

DACCS Direct Air Carbon Capture and Storage.

DESNZ Department of Energy Security and Net Zero.

Drawdown Project Drawdown was set up in 2014 and published a report in 2017, drawing on the efforts of a large group of researchers. The report provides a set of 100 measures to avoid climate change, ranking them by effectiveness and estimating the effect that each might have 2017-2050.

DRS Deposit Return Scheme. For more on this, go to Resource.co and search from there.

DTS Distributor Takeback Scheme. For more on this, go to Resource.co and search from there.

Dunkelflaute (literally 'dark doldrums' or 'dark wind lull'): a period of time in which little or no energy can be generated with wind and solar power, because there is neither wind nor sunlight. In meteorology, this is known as anticyclonic gloom. Source: Wikipedia. This for example was the dunkelflaute of 13 December 2024 (here grey=nuclear, yellow=solar, light blue=wind, light brown=gas. Data from Gridwatch https://gridwatch.co.uk/.

E

EN 13432 An EU standard for compostable plastics.

Energie Sprong Whole house refurbishment and new build standard and funding approach. The Energie Sprong standard focuses on creating desirable homes to the very best energy standard available. It uses the money that would normally be paid on energy bills and maintenance to pay for retrofit work. [More]

EPR Extended Producer Responsibility: "a ... strategy to reach an environmental objective of a decreased total environmental impact of a product, by making the manufacturer of the product responsible for the entire lifecycle of the product and especially for the take-back, recycling and final disposal". For more on this use Wikipedia or go to Resource.co and search from there.

For more on UK packaging EPR, see Second Nature 047.

F

Flygskam A Swedish word meaning "flight shame"; guilt associated with air travel.

Footprint see carbon footprint.

Fugitive Emissions The release to the atmosphere of GHGs from equipment and processes eg refrigeration and aircon systems, fire suppression systems, and the purchase and release of industrial gases. Fugitive emissions are Scope 1 emissions.

G

GHG GreenHouse Gas. The Kyoto Protocol lists carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulphur hexafluoride (SF6), and nitrogen trifluoride (NF3) as greenhouse gases.

Goldsmith Street A development of Passivhaus social housing for Norwich City Council. It won the 2019 The Royal Institute of British Architects (RIBA) Stirling Prize. [More from RIBA] See also Could this be the start of proper social housing? Spoiler Alert: it could have been, but it turned out not to be.

Green hydrogen is made from renewable electricity by electrolysis. There is a presentation on this, The Colours of Hydrogen.

Greenwashing the practice of making exaggerated or misleading claims about the 'greenness' of a product or service.

Grey hydrogen most hydrogen used in industry is ‘grey’: it’s made by steam methane reforming (SMR) using natural gas. SMR is an endothermic reaction and requires significant input of energy to provide the necessary heat and pressure. Some 6% of global natural gas production is used for SMR. There is a presentation on this, The Colours of Hydrogen.

GSHP Ground Source Heat Pump.

H

HDPE High-Density Polyethylene; what plastic milk bottles are made out of.

HVDC High-Voltage Direct Current. Long-distance transmission paths such as the UK's interconnector with France use DC because it has lower transmission losses than Alternating Current (AC).

I

IPCC the Intergovernmental Panel on Climate Change; a UN body whose role is to provide governments at all levels with scientific information that they can use to develop climate policies.

J

Jatropha a crop whose oil is promoted as a biofuel. [More in Wikipedia]

K

L

LCCC Low Carbon Contracts Company. Almost all generators of low-carbon electricity are contracted with NESO indirectly via the LCCC, a company wholly owned by UK government. LCCC uses a financial instrument called a Contract for Difference.

LDPE Low-Density Polyethylene; what plastic bags are made out of.

M

MINERGIE-P see Passivhaus.

MSW Municipal Solid Waste - the material that goes to landfill or incineration.

N

NESO National Electricity System Operator.

O

ONS (UK) The Office of National Statistics.

P

Passivhaus a standard for energy efficiency which reduces a building's ecological footprint. It results in buildings that require little energy for space heating or cooling. A similar standard, MINERGIE-P, is used in Switzerland.

PERN Packaging Export Recovery Note; see Recycling in the UK.

PET Polyethylene Terephalate; a common type of polyester used to make fibres and drinks bottles.

PLA Polylactic Acid; a bioplastic.

PP Polypropylene.

PPA Power Purchase Agreement; a contract between a generator and (usually) a corporate buyer, outside the wholesale electricity market administered by NESO. For example, in Oct 2024 Tesco signed a 15-year PPA to buy 65% of the power from the Cleve Hill Solar Farm, which is currently being built in Kent. It came shortly after Sainsbury's announced that it will buy all the power from the Pines Burn Wind Farm.

ppm parts per million.

PRN Packaging Recovery Note; see Recycling in the UK.

PV PhotoVoltaic: often used as shorthand for 'solar panel'; not to be confused with solar thermal / solar hot water panel.

Q

R

Radiative Forcing or climate forcing is the difference between sunlight absorbed by the Earth and energy radiated back to space. A system in thermal equilibrium has zero radiative forcing. For the aviation sector the climate impact of radiative forcing is estimated to be considerably larger than the impact of direct CO2 emissions, because GHGs are released at altitude. A multiplier of 1.9 on direct emissions is often used.

RAM Recycling Assessment Methodology | Defra 4 September 2025. RAM is used to categorise recyclables liable to fees under UK packaging EPR.

REGO Renewable Energy Guarantees of Origin.

REMA Review of Electricity Market Arrangements.

RVM Reverse Vending Machine. RVMs take in recyclables (PET bottles, say) and return vouchers or points that can be redeemed in shops.

S

SAF Sustainable Aviation Fuel. SAF can be derived from oils or fats (including used cooking oil or tallow) or from municipal solid waste, agricultural residues, or sewage. It can be made from hydrogen and captured carbon using renewable electricity.

Scope the Greenhouse Gas Protocol categorises emissions into three 'scopes'. Scope 1 covers direct emissions from owned or controlled sources (fuel, company vehicles, fugitive emissions). Scope 2 covers indirect emissions from the generation of purchased electricity, steam, heating and cooling. Scope 3 includes all other indirect emissions that occur in a company’s value chain (purchased goods and services, business travel, employee commuting, waste disposal, use of sold products, transportation & distribution (upstream and downstream), investments, leased assets and franchises).

SDG (UN) Sustainable Development Goal. The 17 Sustainable Development Goals are at the heart of the 2030 Agenda for Sustainable Development, adopted by all UN Member States in 2015.

Spectrum of Allies a model that puts people on a spectrum between “active opposition” and “active allies”. People that will be attracted to a u3a climate group are likely to be neutral (probably concerned neutrals) and passive allies. The aim of the group is to move people anticlockwise on the diagram to become active allies; ‘active’ not ‘activist’ note – someone who is doing something to reduce their impact on the environment. It is also assumed that allies, passive and active, are more likely to support green measures when our politicians get round to them.

See also https://ensia.com/voices/climate-change-deniers/: “instead of wasting time trying to convert opponents, we should invest it in motivating passive allies to act”.

Sustainable Aviation Fuel see SAF.

Sustainable Development Goals see SDG.

T

Tipping point (ecological): a set of conditions of an ecological system where further perturbation will cause change to a new state and prevent the system from returning to its former state.

U

Upcycling transforming unwanted materials into new products perceived to be of greater quality, artistic value or environmental value.

V

W

WEEE Waste Electrical and Electronic Equipment.

Wishcycling putting something into a recycling bin in the hope that it will prove to be recyclable. It is sometimes called aspirational recycling.

WMO World Meteorological Organisation.

WSHP Water Source Heat Pump.

X

Y

Z

Zero Carbon Britain (ZCB) a report from CAT which "models a technically robust endpoint where we have achieved net zero GHG emissions". Reduced energy consumption is at the heart of this model. There is comment on ZCB and similar models in Second Nature 017.