Climatepedia
Comprehensive Climate Dictionary - A detailed reference guide providing definitions for important climate-related terms
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]
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.
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.
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]
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.
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.
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.
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. Source: BBC Climate Glossary.
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.
H
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.
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
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 Turkey.
Net-Zero Emissions
Achieving a balance between greenhouse gas emissions produced and greenhouse gas emissions removed from the atmosphere. Many countries and organizations have set net-zero targets by 2050 to limit global warming.
O
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]
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.
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.
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.
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.
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.
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 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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