Glossary

We have included this Glossary for reference.

It has definitions for terms used throughout the four weeks. You aren’t expected to remember all the new terms you come across in this four-week course.

You can refer to the Glossary throughout the course by returning to this step or by downloading the PDF version, which is available in the Downloads section.

If you come across any other words that you would like us to add to the Glossary, please add them to the Comments section. These can then be added for the next run of the course.

Select the hyperlinked letters below (shown in pink) to jump to alphabetical sections of the Glossary.

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

A

Agroecology

A sustainable approach to farming that integrates ecological principles, improves biodiversity, and supports local communities.

Anthropocene

A proposed epoch marking significant human impact on Earth’s systems, though critics argue it oversimplifies and overlooks systemic inequalities.

Anthropogenic climate change

Climate change driven by human activities that produce greenhouse gases, primarily fossil fuel burning and deforestation. The ongoing climate change (or climate crisis) we are in is overwhelmingly driven by human activity (anthropogenic). In this course and in most places, ‘climate change’ is therefore used interchangeably with ‘anthropogenic climate change’.

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B

Backcasting

A planning method where you envision a desired future and work backward to identify steps needed to achieve it.

Business as usual

Continuing current practices without significant changes, often used to describe scenarios where no additional climate action is taken.

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C

Carbon 

Often used as shorthand for carbon dioxide (CO₂) or greenhouse gases more broadly, especially in terms like ‘carbon emissions’, ‘carbon footprint’ or ‘decarbonisation’.

Carbon budget

The maximum amount of carbon dioxide (CO₂) that can be emitted in total (globally and over time) if we are to limit global warming to a specific level, such as 1.5°C or 2°C above pre-industrial levels.

Carbon debt

A country’s or entity’s liability or responsibility for the climate change impacts caused by its historical emissions (of CO₂ and other greenhouse gases).

Carbon dividends

Payments made to citizens from the revenue generated by a carbon tax, intended to offset negative impacts of increased costs from carbon pricing.

Carbon footprint

The carbon footprint of a good or service represents the total greenhouse gas emissions generated in its production or provision, considering its entire supply chain. The carbon footprint of a person, entity or event represents the total greenhouse gas emissions generated by the activities (largely consumption activities) of this person, entity, or event, considering the entire supply chain of the goods or services consumed. The carbon footprint is usually measured in CO₂ equivalents.

Carbon (dioxide) removals (also known as carbon sequestration or negative emissions)

Human activities or human-enhanced natural processes that remove CO₂ from the atmosphere, such as tree planting, permaculture, or direct air carbon capture and storage.

Carbon sink 

A natural system or technology that absorbs and stores carbon dioxide from the atmosphere, such as forests, soil, or oceans, or CCS.

Carbon tax 

A fee imposed on CO₂ emissions or the carbon content of fuels and activities, designed to reduce greenhouse gas emissions by making fossil fuels more expensive.

Climate anxiety

A deep worry about the impacts of the climate crisis, often tied to feelings of a lack of action and individual powerlessness.

Climate change

Global-scale changes in Earth’s climate, including changes in temperatures, rainfall patterns, sea level, and extreme weather events, primarily driven by human activities like burning fossil fuels and deforestation that lead to global warming.  

Climate chaos / Climate crisis / Climate emergency

Synonyms for “climate change” used to highlight urgency and severity.

Climate injustice

The injustice implied in the unequal responsibility for and unequal impacts of climate change, in particular the fact that marginalised communities and poorer nations bear the greatest impacts despite contributing the least to the problem.

Climate justice

The principle that efforts to tackle the climate crisis need to address historical climate injustice, by promoting equity, protecting vulnerable communities, and tackling the root causes of climate injustice.

CO₂

Carbon dioxide, the greenhouse gas or heat-trapping gas that contributes overall most to climate change. 

CO₂e (carbon dioxide equivalent)

CO₂e (carbon dioxide equivalent) is a metric measure that compares the impact of different greenhouse gases by expressing them in terms of the amount of CO₂ that would have the same warming effect.

COPs

Conferences of the Parties to the United Nations Framework Convention on Climate Change (UNFCCC), where global leaders meet annually to negotiate international climate targets and principles for international collaboration.

Cumulative emissions

The total amount of CO₂ and other long-lived greenhouse gases that a country or entity has emitted over time, highlighting their overall responsibility for climate change.

CCS (carbon capture and storage)

A technology that captures CO₂ emissions from industrial processes or power plants and stores them underground to prevent them from entering the atmosphere.

Clean energy

Energy sources that produce little to no greenhouse gas emissions, such as solar, wind, hydro and geothermal, often contrasted with ‘dirty’ energy from fossil fuels.

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D

Decarbonisation

The process of reducing carbon dioxide and greenhouse gas emissions, typically by transitioning to renewable energy and more sustainable practices.

Drawdown

The process of removing greenhouse gases, particularly carbon dioxide, from the atmosphere through methods like sequestration or negative emissions technologies, to reduce accumulated emissions and mitigate climate change impacts.

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E

(Energy) efficiency

The amount of energy (or other resources) used or required to perform a certain task through a particular technology or system. Improving (energy) efficiency means to reduce the amount of energy (or resources) used for a given task, which helps to cut down waste and emissions.  

Emissions

Shorthand for greenhouse gas emissions, that is, the release of greenhouse gases (such as CO₂ or methane) into the atmosphere, primarily from fossil fuel burning, agriculture, and deforestation.

Equity

A notion of fairness that accounts for and addresses differences in responsibility, resources, and vulnerability across countries and communities. For example, equity principles would suggest that those most responsible for causing the climate crisis are the most responsible for tackling it, or that the most vulnerable receive additional support and protections.

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F

Front groups

Organisations that appear independent but are secretly funded by companies or industries to promote their interests, often spreading misinformation.

Fossil fuels (also known as hydrocarbons)

Carbon-based energy sources like coal, oil, and natural gas, whose combustion releases CO₂ and is globally the overwhelming source of greenhouse gas emissions. Natural gas (methane) is itself a very potent greenhouse gas, and thus releasing it into the atmosphere strongly contributes to global warming also when it’s not burned.

Fracking

A method of extracting oil and natural gas by injecting high-pressure fluid into underground rock formations, which is often criticised for its even greater environmental and health impacts.

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G

Global North

High-income, industrialised countries (primarily in Europe, North America, and parts of Asia) that are historically responsible for the vast majority of global emissions and thus for the climate crisis, as they have emitted much more per person than the global average.

Global South

Lower-income and developing countries, often in Africa, Latin America, and Asia, that are the most vulnerable to climate impacts but have contributed very little to emissions.

Global warming / global heating

The rise in Earth’s average temperature due to human-caused greenhouse gas emissions, leading to widespread environmental impacts.  

Greenhouse gases

Gases like carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O) that accumulate in the atmosphere and trap heat, thus contributing to climate change.

Greenhouse effect

The process by which greenhouse gases in the atmosphere trap heat on the planet. While natural concentrations of greenhouse gases in the atmosphere keep the Earth warm enough for life, human activity amplifies the greenhouse effect by emitting vast additional quantities of greenhouse gases into the atmosphere, thus making the Earth hotter and causing dangerous climate change.

Geoengineering

Large-scale interventions into Earth systems, for example installing mirrors in space or creating artificial clouds, in order to offset the warming effect of human-made greenhouse gas emissions.

Green (eg green energy, green technologies, green products)

Refers to practices, products, technologies, or energy sources that generate relatively fewer emissions (and/or are otherwise less environmentally harmful) than the predominant/conventional ones.

Green growth

The idea that continued economic growth could be made compatible with tackling the climate crisis (and other ecological crises) through renewable energy, efficiency improvements, and other technological improvements.

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H

Heat-trapping gases

Greenhouse gases, such as carbon dioxide (CO₂) and methane, that accumulate in the atmosphere and trap heat on the Earth, thus driving climate change.

Historical responsibility

The concept that countries or entities that have emitted the most greenhouse gases over time have a greater obligation to tackle the climate crisis.

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I

Industrial revolution

A historical period starting in the 18^th century, marked by rapid industrial and technological advancements and expansion, which also began the large-scale use of fossil fuels, including for the steam engine.

Intergovernmental Panel on Climate Change (IPCC)

The United Nations’ scientific expert body on climate change, often seen as the most authoritative body on the science of climate change. Its reports reflect the consensus of leading scientists while also being subject to political review and approval by governments.

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J

Just transition

A framework for ensuring that the shift to a low-carbon economy is fair, protecting the livelihoods and rights of workers and communities impacted by the change.

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L

Low-carbon (society/economy/technology/system)

A society, technology, economy or system that minimises greenhouse gas emissions, such as renewable energy, permaculture, or electrified public transport.

Loss and damage

The irreversible losses and damages that have been suffered as a consequence of climate change, such as destroyed ecosystems or lost livelihoods. Global South countries and vulnerable communities have suffered the vast majority of loss and damage to date.

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M

(Climate) Mitigation

Efforts to reduce or prevent greenhouse gas emissions, including transitioning to renewable energy, reducing energy demand, improving energy efficiency, reducing animal agriculture, and restoring natural ecosystems.

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N

Nature-based solutions (also known as natural climate solutions)

Actions to protect, restore or enhance natural processes that remove CO₂ from the atmosphere or provide protections against climate impacts, for example reforestation or wetland restoration.  

Nationally determined contribution (NDC)

The climate targets and action plans submitted by countries under the Paris Agreement, detailing how they will reduce emissions and adapt to climate change.

Neocolonialism

The continuation of colonial power dynamics or inequalities through indirect means, such as economic, political, or cultural influence over formerly colonised regions. The climate crisis contributes to neocolonial inequalities, as formerly colonising countries, through their excessive emissions, indirectly harm formerly-colonised countries via climate change impacts.

Net emissions

The net balance of greenhouse gas emissions into the atmosphere minus carbon dioxide removals from the atmosphere, calculated to reflect the net impact on climate change.

Net-zero (emissions)

A situation where the amount of greenhouse gases emitted is exactly balanced by the amount of CO₂ removed from the atmosphere, such that there are on balance zero net emissions. Reaching net-zero emissions require a large reduction in emissions, accompanied with carbon removals to balance the remaining emissions.

Negative-emission technologies (NETs)

Methods or technologies designed to remove CO₂ from the atmosphere, such as direct air carbon capture and storage (DACCS) or bioenergy with carbon capture and storage (BECCS).

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P

Paris Agreement

A landmark international treaty adopted in Paris in 2015 as part of the United Nations climate negotiations, committing to limit global warming to well below 2°C and aiming to limit warming to 1.5°C, above pre-industrial levels.

Passenger-kilometre

A passenger-kilometre is a measure of passenger travel demand, allowing comparisons of total transport volume across countries or modes (eg train versus plane). It also enables comparisons of CO₂ emissions per passenger-kilometre, revealing the emissions intensity of different transport modes.

Permaculture

A design philosophy that integrates agriculture and ecosystems to create sustainable and self-sufficient systems, mimicking natural processes.

Planetary boundaries

Ecological limits related to processes of human-driven environmental change and damage (eg climate change, biodiversity loss), where transgressing these limits poses fundamental risks to the functioning of Earth’s life support systems that human civilisation depends upon for survival and flourishing.

Pluralistic ignorance

A situation where people wrongly assume others hold different views, leading them to conform to what they mistakenly perceive as the majority opinion.

Post-growth

A societal paradigm which prioritises human wellbeing, fairness and ecological sustainability and recognises the need to abandon the pursuit of economic growth due to its ecological unsustainability and social harms.

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R

Rebound effect

When efficiency improvements lead to increased overall consumption, offsetting some of the expected environmental benefits. For example, when cars become more fuel-efficient, people often drive more because of lower fuel costs per kilometre.

Reforestation

The process of planting trees in areas where forests have been depleted, helping to restore ecosystems and combat climate change by removing CO₂ from the atmosphere.

Renewable energy

Energy sources like solar, wind, hydro, and geothermal that are naturally replenished and cause minimal CO₂ emissions and other environmental impacts, compared to fossil fuels.

Restoration story

A narrative framework that identifies a crisis, its causes and mobilises collective action to restore harmony. Popularised by George Monbiot, it emphasises the power of compelling stories to drive transformative change.

Retrofitting

Upgrading existing buildings or infrastructure to improve energy efficiency, reduce emissions, or meet modern sustainability standards. In the context of this course, this mainly refers to retrofitting better thermal insulation in buildings, to reduce heating or cooling requirements.  

Rewilding

A conservation approach focused on restoring natural processes and ecosystems, often by reintroducing native species and allowing landscapes to recover with minimal human intervention.

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S

Scope 1 emissions

Direct emissions from sources that an organisation owns or controls, such as gas boilers in buildings, coal furnaces in a factory or fuel combustion in company vehicles.

Scope 2 emissions

Indirect emissions from the production of electricity, heating or cooling purchased by an organisation.

Scope 3 emissions

All other indirect emissions in an organisation’s value chain, including those from suppliers, employee commuting and product use.

Sequestration (see also carbon removal)

The process of capturing and storing carbon dioxide from the atmosphere, often in natural systems like forests or engineered methods like carbon storage technologies.

Signalling

Demonstrating values or beliefs through actions, inspiring others with shared values to act similarly.

Social conformity

The tendency of individuals to align their actions or beliefs with those of a group, often influenced by perceived norms or behaviours.

Social contagion

A phenomenon where behaviours, emotions, or ideas spread through a group, as people mimic the actions of others.

Status quo

The existing state of affairs, often used in the context of current elites seeking to maintain current systems and practices and obstructing change, in particular with regards to the economic or political system.

Sufficiency

The concept of something being enough (for meeting basic needs) but not too much (for ensuring ecological sustainability). Sufficiency is often applied to consumption or associated resource use. Pursuing sufficiency means to ensure ‘sufficient’ access to necessities for everyone (increasing consumption for deprived people), while reducing excess consumption (reducing consumption of overconsuming people).

Sustainability

The practice of meeting the needs of present generations in an ecologically and economically sustainable way, in order to not compromise the ability of present and future generations to meet their needs.

Sustainable transport 

Modes of transport that have a lower environmental impact, such as cycling, walking, or public transit powered by renewable energy.

Systemic change (or system change)

Transformational changes that address the root causes of interconnected issues, such as economic and political systems that perpetuate environmental and social crises.

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T

Technological capacity

The ability of a society or organisation to develop and implement advanced technologies to address challenges like the climate crisis.

Thermal blanket

A metaphor for the effect of greenhouse gases trapping heat in Earth’s atmosphere and thus warming the planet, similarly to how a blanket retains heat and warms the person and under the blanket.

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U 

United Nations Framework Convention on Climate Change (UNFCCC)

The process of the United Nations to negotiate and advance international climate targets, policies and actions and national contributions to these.

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V

Vested interest(s)

A personal interest in promoting or protecting systems, policies and other matters that are to one’s own advantage (economically, politically, etc). The term ‘vested interests’ is also used to refer to persons or groups that have a vested interest in a matter. For example, fossil fuel companies are referred to as ‘vested interests’ in the context of climate action. 

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Z

Zero-carbon (activity/technology/energy/society)

Activities, processes, energy sources or societies that produce no greenhouse gas emissions and thus contribute to tackling the climate crisis and building a sustainable neutral future.

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