Comprehensive Climate Dictionary

This dictionary provides detailed definitions for important climate-related terms, organized alphabetically to serve as a reference guide.

A

Abrupt Climate Change

Large-scale climate system changes occurring over a few decades or less, persisting for decades and causing substantial disruptions.[1]

Adaptation

The process of adjusting to current or expected climate change effects. Adaptation can help reduce harm or exploit beneficial opportunities associated with climate change. Strategies may include building flood defenses, implementing drought-resistant crops, or designing buildings for future climate conditions.

Additionality

A criterion for assessing whether an emissions reduction or removal would have occurred without the intervention. Critical for credible carbon offsets and climate finance.

Aerosols

Tiny solid particles or liquid droplets suspended in the atmosphere. They can be natural (volcanic ash, sea spray) or human-made (smoke, soot). Aerosols influence climate by scattering or absorbing radiation and affecting cloud formation.

Albedo

The proportion of solar radiation that is reflected by a surface. High albedo surfaces (like ice and snow) reflect more sunlight back to space, helping cool the Earth. Low albedo surfaces (like forests and oceans) absorb more solar energy, contributing to warming.

Anthropogenic

Resulting from or produced by human activities. In climate science, this refers to greenhouse gas emissions, land use changes, and other human-induced factors that affect climate.

Assessment Report (AR6)

The sixth comprehensive scientific assessment by the IPCC, synthesizing the latest knowledge on climate science, impacts, adaptation, and mitigation.

Attribution (Detection and Attribution)

The process of evaluating the relative contributions of multiple causal factors to observed climate changes and events.[2]

Aerosol–Cloud Interactions

Effects of aerosols on cloud microphysics and lifetimes that alter Earth's radiation budget and precipitation.[3]

Assigned Amount Unit (AAU)

The unit representing the total amount of greenhouse gases an Annex B country is permitted to emit during a Kyoto Protocol commitment period. AAUs are tradable under certain mechanisms and relate to compliance accounting.

Adaptation Fund

A fund created to finance projects and programmes that help developing countries adapt to the adverse effects of climate change.

Annex I Countries

The industrialised countries and economies in transition under the Kyoto Protocol that have specific emission reduction commitments.

Annex II Countries

A subgroup of Annex I countries with special obligations to provide financial resources and transfer technology to developing countries under the Kyoto Protocol.

AOSIS (Alliance of Small Island States)

An international coalition of small island and low-lying coastal states particularly vulnerable to sea-level rise and other climate impacts; plays a prominent role in climate negotiations.

AR4 / AR5 (IPCC Assessment Reports)

The IPCC Fourth (AR4, 2007) and Fifth (AR5, 2013-2014) Assessment Reports providing comprehensive syntheses of climate science, impacts and policy-relevant findings. Source: BBC glossary.

Afforestation

The establishment of a forest on land that has not been forested for a long period or has not historically contained a forest. This process creates new forests and can help mitigate climate change through carbon sequestration.

Anthropogenic Climate Change

Changes to the climate that are caused by human activity, primarily through the burning of fossil fuels which adds greenhouse gases to the atmosphere. Scientific evidence overwhelmingly points to anthropogenic factors as the main source of the rapid climate changes currently being observed.

Atmosphere

The layer of gases surrounding the Earth, which is essential for supporting life and regulating the planet's climate. It is composed of several layers and is highly sensitive to changes in the concentration of greenhouse gases.

B

BAU (Business as Usual)

A reference scenario that projects future emissions assuming no additional climate policies or measures beyond those already in place. Used as a baseline to compare mitigation pathways.

Baseline

The state against which change is measured, often referring to emissions levels in a reference year or scenario.

Biodiversity

The variety of plant and animal life in a particular habitat or ecosystem. Climate change threatens biodiversity through habitat loss, altered seasonal patterns, and increased extreme weather events.

Biofuel

Fuel derived from organic matter (biomass), such as plants, agricultural waste, or algae. Biofuels are considered renewable alternatives to fossil fuels, though their sustainability depends on production methods.

Biomass

Organic material from plants and animals, including wood, agricultural residues and organic waste, that can be used for energy production or as feedstock. Biomass can act as a renewable energy source when managed sustainably.

Blue Carbon

Carbon captured and stored by coastal and marine ecosystems, particularly mangroves, salt marshes, and seagrass beds. These ecosystems sequester carbon at rates much higher than terrestrial forests.

Black Carbon (BC)

Light‑absorbing carbonaceous aerosol produced by incomplete combustion; contributes to atmospheric warming and snow or ice darkening.[4]

Baseline/Reference Scenario

A scenario that describes future emissions without additional climate policies.[5]

Bali Action Plan / Bali Roadmap

A set of negotiations and an action plan agreed in Bali in 2007 to chart a course for post-Kyoto emissions reductions, shaping subsequent international climate negotiations. Source: BBC glossary.

Biodiversity Loss

The decline and disappearance of the variety of life on Earth, including diversity within species, between species, and of ecosystems. This crisis is driven by human activities like habitat loss and overexploitation, and it threatens the ecosystem services upon which humanity depends.

C

Carbon Budget

The estimated amount of carbon dioxide that can be emitted globally while still having a reasonable chance of limiting global temperature rise to a specific target (e.g., 1.5°C or 2°C above pre-industrial levels).

Carbon Capture and Storage (CCS)

Technology that captures CO₂ emissions from sources like power plants and industrial processes, then transports and stores it underground to prevent it from entering the atmosphere.

Carbon Dioxide (CO₂)

A greenhouse gas produced naturally through respiration and volcanic eruptions, but also through human activities like burning fossil fuels and deforestation. It's the primary greenhouse gas responsible for human-induced climate change.

Cap and Trade

A market-based mechanism where a cap is set on emissions and businesses or countries can buy and sell allowances to emit within that cap; the EU ETS is a prominent example.

Carbon Footprint

The total amount of greenhouse gases emitted by an individual, organization, product, or activity over a given period, typically expressed in CO₂-equivalent.

Carbon Intensity

A measure of the amount of greenhouse gas emissions produced per unit of economic output (e.g., per unit of GDP) or energy generated. Lower carbon intensity indicates fewer emissions per unit.

Carbon Leakage

The phenomenon where strict emissions regulations in one country cause industry to relocate to countries with weaker regulations, potentially shifting emissions rather than reducing them globally.

Carbon Neutral

A state where activities result in no net release of CO₂ to the atmosphere. This can be achieved by reducing emissions and balancing remaining emissions with removals, or by purchasing offsets.

Carbon Offsetting

Compensating for emissions by funding an equivalent emissions reduction elsewhere, for example through planting trees or investing in clean energy projects.

Certified Emission Reduction (CER)

A carbon credit issued under the Clean Development Mechanism (CDM) that represents one tonne of CO₂ equivalent reduced or sequestered.

CFCs

Chlorofluorocarbons: synthetic compounds once used in refrigeration and aerosols that deplete stratospheric ozone and act as potent greenhouse gases.

Clean Development Mechanism (CDM)

A Kyoto Protocol mechanism allowing developed countries to finance emissions reduction projects in developing countries and receive credits in return.

Capacity Building

Activities and programs that strengthen the abilities of individuals, organizations and societies to plan, implement, and sustain effective climate action, including training, institutional development and knowledge transfer.

Carbon Sequestration

The process of storing carbon dioxide, either naturally (for example in forests and soils) or through technological means such as geological injection. Carbon sequestration is a key concept in mitigation and complement to carbon capture technologies.

Geological sequestration

The injection and long-term storage of captured CO₂ into deep underground geological formations as a form of carbon storage.

Clean coal

Technologies intended to reduce emissions from coal-fired power generation, including carbon capture and storage, although the term remains controversial due to lifecycle emissions and feasibility concerns.

Carbon Cycle

The continuous biogeochemical process that moves carbon atoms between the Earth's atmosphere, oceans, land, and living organisms. Human activities, such as burning fossil fuels, are disrupting this cycle by releasing vast amounts of stored carbon into the atmosphere.

Carbon Neutrality

A state achieved when the amount of carbon dioxide emitted into the atmosphere is balanced by an equivalent amount being removed or offset. This is different from "zero carbon," as it allows for residual emissions to be compensated for through actions like reforestation or carbon capture.

Carbon Pricing

A climate policy approach that places a monetary cost on greenhouse gas emissions to encourage polluters to reduce their use of fossil fuels. The two main forms are carbon taxes, which set a direct price on emissions, and cap-and-trade systems, which set a limit on total emissions and allow companies to trade allowances.

Carbon Sink

Any natural or artificial system that absorbs more carbon from the atmosphere than it releases, such as forests, oceans, and soil. These sinks play a vital role in regulating the carbon cycle and mitigating climate change.

Circular Economy

An economic system where materials are designed to be kept in circulation through processes like reuse, refurbishment, and recycling, thereby eliminating waste. This model decouples economic activity from the consumption of finite resources and aims to regenerate natural systems.

Climate

The long-term pattern of weather in a particular region, typically averaged over a period of 30 years or more. It is the expected condition based on decades of data, as opposed to weather, which is the atmospheric state at a specific time and place.

Climate Change

A long-term shift in global or regional climate patterns, including changes in temperature, precipitation, and wind. While natural shifts occur, the current changes are primarily driven by human activities that increase greenhouse gas levels in the atmosphere.

Climate Feedback

A process within the climate system that can either amplify (positive feedback) or dampen (negative feedback) an initial warming or cooling trend. For example, melting ice reduces Earth's reflectivity, causing more warming, which is a positive feedback loop.

Climate Justice

A framework that addresses climate change as an ethical and political issue, focusing on the inequity that the least responsible for the crisis are often the most vulnerable to its impacts. It calls for equitable distribution of the burdens of climate impacts and the benefits of climate action, based on principles like human rights and differentiated responsibilities.

Climate Model

A computer simulation that uses mathematical equations to represent the interactions of the atmosphere, oceans, land surface, and ice. Scientists use these models to understand the dynamics of the climate system and make projections about future climate scenarios.

Climate Refugee

A term used to describe people displaced due to climate change impacts, though it has no clear legal definition under international law. These individuals are not covered by the 1951 Refugee Convention, which applies only to those fleeing persecution.

Climate Resilience

The capacity of social, economic, and ecological systems to anticipate, cope with, and recover from a hazardous climate event or trend. Building resilience involves implementing measures to manage risks and adapt to new climate-induced conditions effectively.

Climate Change Commitment

The unavoidable future climate change that will occur because of past and present greenhouse gas emissions, due to inertia in the climate system and slow-responding components such as the oceans and ice sheets.

Climate Sensitivity

The equilibrium change in global mean surface temperature following a doubling of atmospheric CO₂ concentration. Climate sensitivity is commonly expressed as a likely range based on climate models and observational constraints.

Climate Tipping Point

A critical threshold in the climate system that, when crossed, can trigger a large-scale, often abrupt, and potentially irreversible change. Examples include the collapse of major ice sheets or the dieback of the Amazon rainforest, which could be triggered even by moderate additional warming.

Conference of the Parties (COP)

The supreme decision-making body of the United Nations Framework Convention on Climate Change (UNFCCC), which meets annually. At these conferences, countries that are party to the treaty assess progress and negotiate multilateral responses to climate change.

D

Decarbonization

The process of reducing carbon dioxide emissions by transitioning to energy sources and industrial processes that produce little or no CO₂.

Deforestation

The permanent removal of trees to clear land for agriculture, urbanization, or other purposes. Deforestation contributes to climate change by releasing stored carbon and reducing Earth's capacity to absorb CO₂.

Desertification

Land degradation in arid, semi-arid, and dry sub-humid areas due to various factors, primarily human activities and climate variations. Climate change accelerates desertification through increased drought and land degradation.

E

Eco-anxiety

Chronic fear or anxiety related to environmental issues and climate change. A psychological response to perceived threats from global environmental crises.

Ecosystem Services

Benefits that people derive from ecosystems, including provisioning services (food, water), regulating services (climate regulation, flood control), cultural services (recreation, spiritual benefits), and supporting services (nutrient cycling).

Emissions

The release of greenhouse gases and their precursors into the atmosphere over a specified area and period. In climate discussions, emissions typically refer to the release of carbon dioxide, methane, and other greenhouse gases.

Extreme Weather

Unusual, severe, or unseasonal weather events that lie at the extremes of the historical distribution. Climate change is increasing the frequency and intensity of extreme weather events like heat waves, droughts, floods, and storms.

Early Warning Systems

Integrated frameworks designed to monitor, forecast, and communicate impending hazards like hurricanes, floods, and heatwaves. These systems enable timely action to reduce risks, save lives, and minimize economic losses from extreme weather events.

Earth's Energy Budget

The balance between the radiant energy that Earth receives from the sun and the energy that flows from Earth back out to space. An imbalance in this budget, caused by factors like increased greenhouse gases, leads to changes in the Earth's temperature.

El Niño-Southern Oscillation (ENSO)

A recurring natural climate pattern involving fluctuating ocean temperatures and atmospheric pressure across the equatorial Pacific Ocean. Its phases, El Niño (warming) and La Niña (cooling), occur in irregular cycles of 2–7 years and can significantly influence weather patterns worldwide.

Emissions Trading

A market-based approach to controlling pollution, also known as "cap and trade," that provides economic incentives for reducing emissions. A government sets a cap on total emissions and issues a limited number of tradable allowances, creating a market price for emissions.

Energy Efficiency

The practice of using less energy to perform the same task or provide the same level of service, thereby eliminating energy waste. Improving energy efficiency is often the cheapest and most immediate way to reduce the use of fossil fuels and cut greenhouse gas emissions.

Enhanced Greenhouse Effect

The intensification of the natural greenhouse effect due to the increase in atmospheric concentrations of greenhouse gases produced by human activities. This process traps more of the sun's energy, causing a warming effect known as global warming.

F

Flexible mechanism

Policy instruments under the Kyoto Protocol (such as Joint Implementation and the Clean Development Mechanism) that allow countries to meet part of their emissions targets by financing reductions elsewhere.

Feedback loop

Processes in the climate system that amplify (positive) or dampen (negative) an initial change; for example, permafrost thaw releases methane which can accelerate warming.

Fossil Fuels

Flammable, carbon-containing materials like coal, oil, and natural gas, formed from the buried remains of prehistoric organisms over millions of years. The combustion of these non-renewable resources is the largest human-caused source of greenhouse gas emissions and the primary driver of climate change.

Fluorinated Gases (F-gases)

Synthetic greenhouse gases including hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulfur hexafluoride (SF₆). These gases have high global warming potentials and long atmospheric lifetimes.

Fugitive Emissions

Unintended or accidental releases of greenhouse gases during extraction, processing, transmission or storage of fossil fuels and industrial activities. Measuring and reducing fugitive emissions is important for accurate inventories and mitigation.

G

Global Warming

The long-term warming of Earth's climate system observed since the pre-industrial period due to human activities, primarily burning fossil fuels. Global warming is an aspect of climate change.

Greenhouse Effect

The warming of Earth's surface and lower atmosphere as greenhouse gases trap heat that would otherwise escape to space. While the natural greenhouse effect makes Earth habitable, human enhancement of this effect is driving climate change.

Greenhouse Gas (GHG)

Gases that trap heat in the atmosphere, including carbon dioxide, methane, nitrous oxide, and fluorinated gases. Increases in these gases due to human activities are the primary driver of climate change.

Global dimming

An observed reduction in sunlight reaching the Earth's surface in some regions, likely linked to airborne particles (aerosols) and air pollution, which can mask some warming caused by greenhouse gases.

Global Warming Potential (GWP)

A metric for comparing the warming impacts of different greenhouse gases relative to carbon dioxide, usually over a specified time horizon such as 100 years.

G77

A coalition of developing nations (Group of 77 plus China) that coordinates negotiating positions in international forums on economic and development issues, including climate negotiations.

Green Climate Fund (GCF)

The world's largest dedicated climate fund, established by the UNFCCC to support developing countries in their efforts to respond to climate change. It aims to mobilize funding at scale for low-emission and climate-resilient projects and programs.

Greenwashing

Practices and marketing that mislead consumers or investors about the environmental benefits of a product, service, or company, often exaggerating or fabricating claims about sustainability.

Green Economy

An economic model that is low-carbon, resource-efficient, and socially inclusive, aiming for sustainable development without degrading the environment. In a green economy, growth is driven by investments that reduce carbon emissions, enhance resource efficiency, and prevent biodiversity loss.

Greenhouse Gas Inventory

A quantified list of an organization's or country's greenhouse gas emissions and their sources, developed using standardized methods. It serves as a tool for understanding, managing, and communicating emissions from various activities.

H

Hockey stick

The name given to reconstructions of past temperatures that show a long-term flat trend followed by a sharp recent rise, producing a chart that resembles a hockey stick. Often cited as evidence of recent anthropogenic warming.

Hydrofluorocarbons (HFCs)

A group of synthetic, human-made gases containing carbon, hydrogen, and fluorine, primarily used for cooling and refrigeration. Although they do not deplete the ozone layer, many HFCs are potent greenhouse gases with high global warming potential.

Hydrological Cycle

The continuous movement of water through evaporation, condensation, precipitation, infiltration and runoff. Climate change alters components of the hydrological cycle, affecting water availability, floods and droughts.

I

Joint implementation (JI)

A Kyoto Protocol mechanism allowing one country to earn emission reduction units from an emission-reduction or removal project in another developed country, used to meet their own targets.

IPCC (Intergovernmental Panel on Climate Change)

The United Nations body responsible for assessing the science related to climate change. It provides policymakers with regular scientific assessments on climate change, its implications, and potential future risks.

Ice Sheet

A large mass of glacial land ice covering more than 50,000 square kilometers (e.g., Greenland and Antarctica). Ice sheets contain large volumes of freshwater and their melt contributes significantly to sea level rise.

Impact Assessment

The systematic evaluation of the potential effects of climate change or policy actions on natural and human systems, often used to inform planning and adaptation measures.

Ice Core

A cylinder-shaped sample of ice drilled from a glacier or ice sheet, containing layers of accumulated snow from past years. Scientists analyze trapped air bubbles, dust, and water isotopes within ice cores to reconstruct past climate conditions and atmospheric composition.

Indigenous Peoples

Communities that are among the first to face the direct consequences of climate change due to their close relationship with the environment and its resources. Climate change disproportionately impacts their health, environments, and cultural practices, exacerbating existing vulnerabilities.

K

Kyoto Protocol

An international treaty added to the UNFCCC that set binding emission reduction targets for industrialised countries. Adopted in 1997 with defined commitment periods.

L

LDCs (Least Developed Countries)

The group of the world's poorest and most vulnerable countries, often given special consideration in climate finance and adaptation discussions under the UNFCCC.

LULUCF (Land Use, Land-Use Change and Forestry)

A greenhouse gas inventory sector that covers emissions and removals of greenhouse gases resulting from direct human-induced land use. This includes activities such as deforestation, afforestation, and the management of forests and agricultural lands.

M

Mitigation

Actions to reduce greenhouse gas emissions and enhance carbon sinks, thereby limiting the magnitude of future climate change. Examples include transitioning to renewable energy, improving energy efficiency, and afforestation.

Methane (CH₄)

A powerful greenhouse gas with a global warming potential 28-36 times that of carbon dioxide over a 100-year period. Major sources include fossil fuel extraction, livestock, wetlands, and waste management.

N

NDC (Nationally Determined Contribution)

A country's national climate plan outlining targets and measures for mitigation and adaptation under the Paris Agreement.

Net Zero

Balancing anthropogenic emissions and greenhouse gas removals over a specified time period, typically by 2050 globally and 2053 for Türkiye.

Net-Zero Emissions

A state in which human-caused greenhouse gas emissions are balanced by an equivalent amount of removals from the atmosphere, stopping further global warming. This is achieved by cutting emissions to a small amount of residual emissions that can be absorbed by natural sinks or other removal measures.

Nitrous Oxide (N₂O)

A colorless gas, also known as laughing gas, that is a powerful greenhouse gas with a long atmospheric lifetime. Major human-related sources include agricultural activities, particularly the use of nitrogen fertilizers, as well as fuel combustion and industrial processes.

O

Ocean Acidification

The ongoing decrease in the pH of the Earth's oceans, caused primarily by the uptake of excess carbon dioxide from the atmosphere. This change in ocean chemistry makes it more difficult for marine organisms like corals and shellfish to build their shells and skeletons.

Ozone (O₃)

A highly reactive gas composed of three oxygen atoms that occurs in both the Earth's upper atmosphere (stratosphere) and lower atmosphere (troposphere). Stratospheric ozone protects life by absorbing harmful UV radiation, while ground-level ozone is a harmful air pollutant and a greenhouse gas.

P

1.5°C Pathway

A scenario of rapid, deep reductions in greenhouse gas emissions aimed at keeping global warming to 1.5°C above pre-industrial levels. Often referenced in IPCC reports and climate policy discussions.[IPCC SR15]

Photosynthesis

The process by which plants, algae and some bacteria convert carbon dioxide and sunlight into organic matter and oxygen, acting as a natural carbon uptake mechanism.

Paris Agreement

A legally binding international treaty on climate change adopted in 2015. Its goal is to limit global warming to well below 2°C, preferably to 1.5°C, compared to pre-industrial levels. Countries submit nationally determined contributions (NDCs) outlining their emission reduction plans.

Permafrost

Ground that remains completely frozen for at least two consecutive years. Permafrost thaw due to climate change releases methane and carbon dioxide, creating a positive feedback loop that accelerates warming.

Per-capita emissions

The total greenhouse gas emissions of a country divided by its population. It provides a per-person perspective on contributions to climate change.

ppm (parts per million)

A unit of concentration commonly used for atmospheric gases, e.g., CO₂ levels are often reported in ppm (parts per million by volume).

R

Renewable Energy

Energy derived from naturally replenishing but flow-limited sources such as sunlight, wind, rain, tides, waves, and geothermal heat. Renewable energy produces minimal greenhouse gas emissions.

Resilience

The ability of a system to absorb disturbances while retaining the same basic structure and ways of functioning. In climate change context, it refers to the capacity to prepare for, respond to, and recover from climate impacts.

REDD+

A UNFCCC framework that stands for "Reducing Emissions from Deforestation and forest Degradation," with the "+" signifying the role of conservation, sustainable forest management, and enhancement of forest carbon stocks. It aims to incentivize developing countries to reduce emissions from forested lands and invest in low-carbon development paths.

Reforestation

The re-establishment of a forest on land that was previously forested but has been converted to another use or had its tree cover removed. This is distinct from afforestation, which involves planting forests on land that has not recently or historically been forested.

Radiative Forcing

The change in the balance between incoming solar radiation and outgoing infrared radiation caused by changes in factors such as greenhouse gas concentrations or solar output, typically measured in watts per square meter (W/m²).

Solar Radiation

Energy emitted by the sun in the form of electromagnetic radiation. Solar radiation is the primary energy source driving Earth's climate system.

S

Sea Level Rise

The increase in average global sea level due to thermal expansion of ocean water and melting of ice sheets and glaciers. Sea level rise threatens coastal communities and ecosystems.

Sustainability

Meeting the needs of the present without compromising the ability of future generations to meet their own needs. Sustainable practices address environmental protection, social development, and economic growth.

Stern review

A landmark 2006 report by economist Nicholas Stern assessing the economics of climate change, arguing that the costs of inaction far outweigh the costs of early mitigation.

Sustainable Agriculture

An approach to farming that meets the needs of present and future generations while ensuring profitability, environmental health, and social equity. It aims to produce nutritious food without compromising the natural resource base upon which future production depends.

Sustainable Development

Development that meets the needs of the present without compromising the ability of future generations to meet their own needs. This approach seeks to balance environmental, social, and economic considerations to create a society where living conditions and resources meet human needs without undermining planetary integrity.

T

Tipping Point

A critical threshold that, when exceeded, leads to large and often irreversible changes in the climate system. Potential tipping points include collapse of the Amazon rainforest, West Antarctic ice sheet collapse, and disruption of the Gulf Stream.

Transition Risk

Risks to companies, investors, and economies arising from the transition to a low-carbon economy, including policy, legal, technology and market changes.

Troposphere

The lowest layer of Earth's atmosphere where most weather occurs, extending from the surface up to about 8–15 km; it contains most of the atmospheric water vapor and aerosols relevant to climate.

Technology transfer

The process by which technological know-how, equipment and practices are shared between countries, often from developed to developing countries, to help reduce emissions and adapt to climate change.

Twenty-twenty-twenty (20-20-20)

A European Union policy package setting three targets for 2020: 20% reduction in greenhouse gas emissions (from 1990 levels), 20% of energy from renewables, and a 20% increase in energy efficiency.

U

UNFCCC (United Nations Framework Convention on Climate Change)

An international environmental treaty negotiated at the 1992 Earth Summit. Its objective is to stabilize greenhouse gas concentrations "at a level that would prevent dangerous anthropogenic interference with the climate system."

V

Vulnerability

The degree to which a system is susceptible to or unable to cope with adverse effects of climate change, including climate variability and extremes. Vulnerability depends on exposure, sensitivity, and adaptive capacity.

W

Water Scarcity

The lack of sufficient available water resources to meet water demands within a region. Climate change exacerbates water scarcity through altered precipitation patterns, increased evaporation, and saltwater intrusion from sea level rise.

Water Vapor

Water in its gaseous state, the most abundant greenhouse gas in the atmosphere. Water vapor acts as a powerful feedback in the climate system, amplifying warming produced by other greenhouse gases.

Wetlands

Ecosystems where water covers the soil or is present at or near the surface, such as marshes and peatlands. Wetlands store significant carbon and provide important biodiversity and flood protection services.

Weather

The state of the atmosphere at a particular place and time regarding temperature, precipitation, wind, and other variables. While weather is what you experience day-to-day, climate is the average weather patterns over a longer period.

Z

Zero-Carbon

Producing no carbon dioxide emissions during operation. Zero-carbon energy sources include solar, wind, hydroelectric, and nuclear power.

Zero Emissions

A state in which no greenhouse gases are emitted to the atmosphere from a given activity or source. Achieving zero emissions often requires switching to non-emitting energy sources and eliminating process-related emissions.

Zero Emissions Commitment

The climate system's remaining warming commitment if anthropogenic emissions were to reach zero, reflecting inertia in the climate system and long-lived forcing agents.

Zero Waste

A set of principles focused on waste prevention and sustainable resource management. The goal is to design all products for reuse, recycling, or composting, eliminating the need for landfills and incineration.

Complete Dictionary

This dictionary contains all important climate terms from A to Z. Each term is detailed with information compiled from IPCC reports, UNFCCC glossary, NOAA, and other reliable sources. This continuously updated resource is an indispensable reference for those working in climate science and policy.

Sources and Further Reading:

• IPCC AR6 and Special Reports
• UNFCCC Glossary and Resources
• NOAA Climate Glossary
• Met Office Climate Change Glossary
• UNDP Climate Dictionary

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