The Climate Dictionary: An everyday guide to climate change

Climate dictionary
Climate dictionary
Also available in Spanish

Climate change is the defining issue of our times. Every day, more and more people are getting involved in climate action.

Veterans in the field are already familiar with the many terms and concepts related to climate change. But if you are new to the discussion, it can be quite challenging to grasp everything at once.

That’s why we prepared this resource of climate change terms and concepts. If you’re struggling to keep up with the climate conversation, the Climate Dictionary is for you.

We invite you to read it, bookmark it, make use of it in your climate action work.

And we promise to update it regularly with new terms, so that we can push for collective climate action together.

Weather vs. Climate

Weather refers to atmospheric conditions at a particular time in a particular location, including temperature, humidity, precipitation, cloudiness, wind, and visibility. Weather conditions do not happen in isolation, they have a ripple effect. The weather in one region will eventually affect the weather hundreds or thousands of kilometers away.

Climate is the average of weather patterns in a specific area over a longer period of time, usually 30 or more years.

Human activity in the industrial age, and particularly during the last century, is significantly altering our planet’s climate through the release of harmful greenhouse gases.

Greenhouse gas emissions

Greenhouse gases are gases that trap heat in the atmosphere, causing global warming and climate change. The main greenhouse gases released by human activity are carbon dioxide, methane, and nitrous oxide, as well as fluorinated gases used for cooling and refrigeration. To prevent catastrophic climate change, the world’s governments must work together to significantly reduce greenhouse gas emissions and keep global warming below the dangerous threshold of 1.5°C.

Global warming vs. Climate change

Global warming is an increase in the Earth’s average surface temperature that occurs when the concentration of greenhouse gases in the atmosphere increases. These gases absorb more solar radiation and trap more heat, thus causing the planet to get hotter. Burning fossil fuels, cutting down forests, and farming livestock are some human activities that release greenhouse gases and contribute to global warming.

Climate change refers to the long-term changes in the Earth’s climate, beyond the increase in average surface temperature. Climate change causes weather patterns to be less predictable, affecting the balance of ecosystems that support life and biodiversity. It also causes more extreme weather events, such as more intense hurricanes, floods, heat waves, and droughts, and leads to sea level rise and coastal erosion by accelerating the melting of glaciers.

Local communities

Climate crisis

The climate crisis refers to the serious problems that are being caused or are likely to be caused by changes in the planet’s climate. Since the 1800s, the Earth’s average temperature has increased by 1.1° C, already causing significant damage in many parts of the world. Scientists expect that an increase beyond 1.5° C would lead to a series of dangerous tipping points that would make many changes irreversible and pose a very serious threat to human civilization.

Tipping point

A tipping point is a threshold after which certain changes caused by climate change become irreversible. These changes may lead to abrupt and dangerous impacts with very serious implications for the future of our planet.

Scientists have already identified several tipping points that have been reached due to the 1.1° C rise in temperature since pre-industrial times. These include the collapse of Greenland’s ice cap and its impact on north Atlantic Ocean currents, large-scale coral die-off, and the melting of permafrost. The impacts of these tipping points range from substantial sea level rise to disrupted weather patterns and the collapse of marine ecosystems upon which billions of people depend on for food and livelihoods.


Mitigation refers to any action taken by governments, businesses, and people to reduce, sequester, or prevent greenhouse gas emissions.

Examples of mitigation include transitioning to renewable energy like wind and solar, investing in carbon-free transportation, promoting sustainable agriculture and land use, planting forests to act as carbon sinks, and changing consumption practices and diet behaviors.

Did you know: To limit global warming to 1.5° C, which scientists have set as the threshold before irreversible climate impacts occur, the world must take mitigation actions to reduce greenhouse gas emissions by 45% before 2030 and reach net-zero CO2 emissions by mid-century.


Adaptation refers to actions that help reduce vulnerability to the current or expected impacts of climate change.

Examples of adaptation include planting crop varieties that are more resistant to drought or changing conditions, managing land to reduce wildfire risks, building stronger flood defenses, relocating infrastructure from coastal areas affected by sea level rise, and developing insurance mechanisms specific to climate-related threats.


Resilience is the capacity of a community or environment to anticipate and manage dangerous climatic events and recover and transform after the ensuing shock, with minimal damage to societal wellbeing, economic activity, and the environment.

Examples of increasing resilience in a community include long-term planning, early warning systems, training for new skills, diversifying the sources of household income, strengthening nature-based solutions, and building robust communal response and recovery capacities.

Nature-based solutions

Nature-based solutions support climate change adaptation and mitigation by using natural systems and processes to restore ecosystems, conserve biodiversity, and enable sustainable livelihoods. They are actions that prioritize ecosystems and biodiversity and are designed and implemented with the full engagement and consent of local communities and Indigenous Peoples.

Examples include planting trees, restoring wetlands, conserving mangrove forests, or switching to regenerative farming practices.

Did you know: Nature-based solutions are seen as a win-win for people and nature. They can create jobs, provide new and more resilient livelihood opportunities, and increase income while also protecting the planet.

Loss and damage

There is no agreed definition of "Loss and damage" in the international climate negotiations. However, the term can refer to the unavoidable impacts of climate change that occur despite, or in the absence of, mitigation and adaptation. Importantly, it highlights that there are limits to what adaptation can accomplish; when tipping point thresholds are crossed, climate change impacts can become unavoidable.

Loss and damage can refer to both economic and non-economic losses. Economic loss and damage can include things like the costs of rebuilding infrastructure that has repeatedly been damaged due to cyclones or floods, or the loss of coastline land (and homes and businesses) due to sea-level rise and coastal erosion.

Non-economic loss and damage include negative impacts that can’t be easily assigned a monetary value. This can include things such as trauma from experiencing a climate-related natural disaster, loss of life, the displacement of communities, loss of history and culture or loss of biodiversity.

Net zero

Reaching net zero emissions entails reducing greenhouse gas emissions from human activity to a threshold where Earth’s carbon sinks can absorb the rest, therefore stopping further increase in the concentration of greenhouse gases in the atmosphere.

Transitioning to net zero requires a complete transformation of our energy, transportation, and production and consumption systems. This is necessary to avert the worst consequences of climate change.

Did you know: To keep global warming below 1.5° C, the world’s governments need to ensure that all greenhouse gas emissions peak by 2025, and reach net zero in the second half of this century. The IPCC has recommended to reduce CO2 emissions globally by 45% before 2030 (compared to 2010 levels) and reach net zero by mid-century.

Net zero

Carbon sink

A carbon sink is anything that absorbs more carbon from the atmosphere than it releases. Forests, wetlands, oceans, and soil are the world’s largest carbon sinks.

Today, human activity, like burning fossil fuels and deforestation, causes more carbon to be released into the atmosphere than the Earth’s natural carbon sinks can absorb, leading to global warming and climate change. Therefore, protecting and expanding carbon sinks is a key strategy for tackling climate change and stabilizing the climate.

Carbon removal vs. carbon capture

Carbon removal is the process of removing greenhouse gas emissions from the atmosphere, through actions such as planting trees or capturing and sequestering carbon from biofuels and bioenergy plants. Carbon removal could slow, limit, or even reverse climate change — but it is not a substitute for cutting greenhouse gas emissions.

Carbon capture and storage is the process of taking emissions produced by power generation or industrial activity and storing them deep underground.

In short, carbon removal is the elimination of carbon emissions after they have entered our atmosphere. Carbon capture and storage is the trapping of carbon emissions just after they’ve been emitted but before they can enter our atmosphere. The efficacy of these processes remains largely untested.

Carbon markets

Carbon markets are trading systems in which carbon is quantified into a “carbon credit” that can be bought and sold. Companies or individuals can use carbon markets to compensate for their greenhouse gas emissions by purchasing carbon credits from entities that remove or reduce greenhouse gas emissions.

One tradable carbon credit equals one tonne of carbon dioxide, or the equivalent amount of a different greenhouse gas reduced, sequestered or avoided. When a credit is used to reduce, sequester, or avoid emissions, it becomes an offset and is no longer tradable.

Circular economy

Presently, we are using more than the available amount of Earth’s natural resources to sustain current levels of human consumption. Estimates show that if we continue on our current path, we will need the equivalent of almost three planets’ worth of natural resources.

Having a circular economy means that economic systems are based on the reuse and regeneration of materials or products, ensuring that production and consumption is done in a sustainable or environmentally friendly way that reduces and reuses waste.

Circular economy approaches can help countries accelerate their transition to more resilient and lower-carbon economies while also creating new green jobs.

Blue economy

The world’s oceans – their temperature, chemistry, currents, and life – drive global systems that make Earth habitable for humankind. Our rainwater, drinking water, weather, climate, coastlines, much of our food, medicines and even the oxygen in the air we breathe, are all provided and regulated by the seas. However, because of climate change, the health of our oceans is now at significant risk.

The "blue economy" concept seeks to promote economic development, social inclusion, and the preservation or improvement of livelihoods while at the same time ensuring environmental sustainability of the oceans and coastal areas.

Blue economy has diverse components, including established traditional ocean industries such as fisheries, tourism, and maritime transport, but also new and emerging activities, such as offshore renewable energy, aquaculture, seabed extractive activities, and marine biotechnology.

Just transition

In the context of climate change, transitioning to a low-carbon or net-zero economy requires massive transformation of our economic systems. Such transformation runs the risk of further increasing social inequality, exclusion, civil unrest, and less competitive businesses, sectors, and markets.

As countries work to meet their climate goals, it’s vital that they ensure the whole-of-society – all communities, all workers, all social groups – are brought along and part of the structural change that takes place.

Ensuring a just transition means that countries choose to green their economy through transition pathways and approaches that reinforce equality and inclusivity. This means looking at the impacts of the transition on different groups of workers across the economy and providing opportunities for training and reskilling that support decent work and aim to leave no one behind.

Just transition

Conference of the Parties (COP)

The annual United Nations conference dedicated to climate change, called “Conference of the Parties” or “COP,” has been organized under the UN Framework Convention on Climate Change (UNFCCC) since 1995. At the 21st COP, or COP21, which took place in 2015, the Paris Agreement was signed.

The conference now brings together all nations who are parties to the Paris Agreement to discuss their next steps to combat climate change and further establish legally binding agreements to support climate action. The next conference, COP28, will take place in the United Arab Emirates in December 2023.

Paris Agreement

The Paris Agreement is a legally binding international treaty aiming to limit global warming to well below 2° C, preferably to 1.5° C, compared to pre-industrial levels. It was adopted by 196 Parties in 2015 at COP21 in Paris and entered into force in 2016.

The Paris Agreement is a landmark achievement in international cooperation on climate change because it is a binding agreement for all Parties to scale up efforts to combat climate change and adapt to its effects. It also provides the instruments for developed nations to assist developing nations in their climate mitigation and adaptation efforts, while creating a framework for transparent monitoring and reporting of results.

Paris Agreement

Nationally Determined Contributions (NDCs)

Nationally Determined Contributions (NDCs) are climate pledges and action plans that each country is required to develop in line with the Paris Agreement goal of limiting global warming to 1.5° C. NDCs represent short to medium-term plans that are updated every five years with higher ambition on climate.

NDCs outline mitigation and adaptation priorities a country will pursue to reduce greenhouse gas emissions, build resilience, and adapt to climate change, as well as financing strategies and monitoring and verification approaches. In 2023, the first in a series of global “stock takes” will assess progress on the implementation of NDCs and Paris Agreement goals.

Long-term strategies

Under the Paris Agreement, countries are invited to communicate long-term strategies for emissions reductions that envision a whole-of-society transformation over several decades, usually up to 2050. LTS documents align to the long-term objectives of limiting global warming and achieving net-zero by 2050.

Long-term strategies look beyond shorter term NDCs and are a guide for countries to pursue low-carbon development, boost innovation, plan for sustainable infrastructure, and promote just and equitable transitions for their workforce.

When countries officially communicate their LTS to the UNFCCC it is called a Long-Term Low Emission Development Strategy (LT-LEDS).

Intergovernmental Panel on Climate Change (IPCC)

The Intergovernmental Panel on Climate Change (IPCC) is an independent body founded under the auspices of the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP).

The IPCC’s main role is to assess the scientific literature and findings on climate change and provide vital scientific information and evidenced-based recommendations to policymakers and the public. It is widely recognized as the most credible source of information related to the science of climate change and its complex analysis of impacts, risks, and adaptation and mitigation options.