Basic terms we encounter in the ActGREEN project related to climate change, nature‑based solutions and decarbonisation.
In the implementation of the
ActGREEN project, alongside experienced project partners — colleagues from the
City of Zagreb (City Office for Reconstruction, Construction, Spatial Planning, Building and Municipal Services; Administrative Service of the City Administration; Department for Preparation and Implementation of EU Projects) — partners from the
University of Zagreb Faculty of Agriculture, as well as the associations
ODRAZ and
HDKA, are also participating.
To facilitate understanding and implementation of activities, we recognised the need to additionally clarify useful topics and terms related to climate change, not only within the partner consortium but also among other project stakeholders, as well as our fellow citizens and enthusiasts.
Climate change refers to long‑term changes in the Earth’s climate. Elements of climate change include rising average temperatures, burning of fossil fuels, deforestation, livestock farming and human activity. In a changed climate, weather patterns become less predictable, disrupt ecosystem balance and cause extreme weather events such as storms, floods, heatwaves and droughts.
The increase in average temperature is caused by higher concentrations of greenhouse gases in the atmosphere, which absorb more solar radiation and trap more of the Earth’s heat.
Nature‑based solutions (NbS) support climate‑change mitigation by using natural systems and processes that restore ecosystems and preserve biodiversity and sustainable living conditions.
These are measures that prioritise nature in its original form, ecosystems and biodiversity, and are designed and implemented with full engagement and consent of local communities and Indigenous populations.
Examples include tree planting, wetland restoration, using plants for insulation on façades and roofs, and transitioning to regenerative agricultural practices.
Green infrastructure: planned green and water surfaces and other spatial nature‑based solutions applied within cities and municipalities, contributing to the preservation, improvement and restoration of nature, natural functions and processes to achieve ecological, economic and social benefits of sustainable development.
Urban heat islands: urbanised areas significantly warmer than their rural surroundings due to artificial infrastructure and human activities.
Decarbonisation means reducing the amount of greenhouse‑gas emissions produced by society, as well as increasing the amount absorbed. This requires changing many, if not all, aspects of the economy — from how energy is produced, to how goods and services are manufactured and delivered, to how buildings are constructed and land is managed.
To achieve the goals of the Paris Agreement and maintain the 1.5° target, governments and businesses must rapidly decarbonise by 2030. Meaningful decarbonisation requires significant investment in low‑carbon infrastructure and transport, renewable energy, circular economy and resource efficiency, as well as land and soil restoration. It also requires rethinking current economic models focused on growth at any cost.
Greenhouse gases are gases that trap the sun’s heat in the Earth’s atmosphere, keeping it warm. Since the beginning of the industrial era, human activities have released dangerous levels of greenhouse gases, causing global warming and climate change.
The main greenhouse gases released by human activities are carbon dioxide, methane, nitrous oxide and fluorinated gases used for cooling and refrigeration.
Carbon dioxide is the primary greenhouse gas produced by human activities, especially through burning fossil fuels, deforestation and land‑use change. Our reliance on fossil fuels has increased atmospheric CO₂ concentrations by 50 percent in the last 200 years.
Methane is another important greenhouse gas responsible for 25 percent of global warming. It is released during the extraction and transport of coal, gas and oil, as well as from landfills and agricultural practices.
To prevent catastrophic climate change, governments worldwide must work together to significantly reduce greenhouse‑gas emissions now and in the coming decades, keeping global warming below the dangerous threshold of 1.5°C.
Carbon footprint is a measure of greenhouse‑gas emissions released into the atmosphere by a person, organisation, product or activity. A larger carbon footprint means more CO₂ and methane emissions and therefore a greater contribution to the climate crisis.
Measuring a carbon footprint includes direct emissions from burning fossil fuels for energy production, heating and land and air transport, as well as indirect emissions from the production and disposal of all food, goods and services consumed.
Carbon footprints can be reduced by switching to low‑carbon energy sources such as wind and solar, improving energy efficiency, strengthening industrial policies and regulations, changing purchasing and travel habits, and reducing meat consumption and food waste.
European Green Deal is the EU strategy adopted to achieve climate neutrality by 2050 and fulfil obligations under the Paris Agreement.
The plan includes a series of initiatives, programmes and regulations aimed at addressing the existential threats of climate change without compromising economic growth and human well‑being. Measures include investing in environmentally friendly technologies, encouraging innovation, developing cleaner forms of transport, decarbonising energy and more.
Paris Agreement is a legally binding international treaty aimed at limiting 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 milestone in international climate cooperation because it obliges all parties to increase efforts to combat climate change and adapt to its impacts. It also provides tools for developed countries to support developing countries in mitigation and adaptation efforts, while creating a framework for transparent monitoring and reporting.
Circular economy is based on reusing materials or products, ensuring that production and consumption occur in a sustainable way that reduces and reuses waste.
Today we use more natural resources than are available. If we continue with current lifestyles and consumption patterns, estimates show we will need resources equivalent to nearly three planets — but we only have one.
Climate neutrality is a state in which human activities do not result in a net effect on the climate system. Achieving this requires balancing remaining emissions with emission removal (carbon dioxide), as well as considering regional or local biogeophysical effects of human activities that affect surface albedo or local climate.
Carbon neutrality or net‑zero CO₂ emissions refers only to gases, not the entire climate system. Carbon neutrality is achieved when anthropogenic CO₂ emissions are balanced by anthropogenic CO₂ removals over a given period.
Net zero means reducing greenhouse‑gas emissions from human activity to a level at which the Earth’s carbon sinks can absorb the remainder, stopping further increases in atmospheric greenhouse‑gas concentrations.
The transition to net zero requires a complete transformation of energy, transport, production and consumption systems. This is necessary to prevent the worst consequences of climate change.
The European Union, through the Green Deal and the European Climate Law, has set a target of reducing emissions by 55% by 2030 compared to 1990 levels.
Carbon sinks are anything that absorbs more carbon from the atmosphere than it releases. Forests, wetlands, oceans and soil are the world’s largest carbon sinks.
Human activities such as burning fossil fuels and deforestation release more carbon than natural sinks can absorb, causing global warming and climate change. Protecting and expanding carbon sinks is therefore a key strategy for climate stabilisation.
Urban sprawl: the physical pattern of low‑density expansion of large urban areas into surrounding agricultural land. Sprawl occurs ahead of main urban‑growth boundaries and involves limited land‑use planning control. Development is uneven, scattered and stretched, often skipping certain areas and leaving agricultural enclaves.
Carbon markets involve trading greenhouse‑gas emissions, where carbon is quantified into carbon‑credit units that can be bought and sold.
Companies or individuals can use carbon markets to offset their excess emissions by purchasing credits from those who remove or reduce greenhouse‑gas emissions. One carbon‑credit unit equals one tonne of CO₂ or the equivalent amount of another greenhouse gas reduced, avoided or absorbed.
Adaptation refers to measures that reduce vulnerability to current or expected impacts of climate change.
Examples include planting drought‑resistant crops, land‑management practices that reduce fire risk, building stronger flood defences, relocating infrastructure from coastal areas affected by sea‑level rise, and developing insurance mechanisms for climate‑related risks. Adaptation reduces the scale of damage.
Mitigation refers to any action taken by governments, businesses or individuals to reduce or prevent greenhouse‑gas emissions or increase carbon sinks.
Mitigation can be achieved by switching to renewable energy, improving energy efficiency, using low‑carbon transport, promoting sustainable agriculture and land use, and changing production, consumption and dietary habits.
Increasing carbon sinks can be achieved through forest and wetland restoration, soil‑health maintenance and protection of terrestrial and marine ecosystems.
Successful mitigation requires supportive legislation, policies and investment.
Climate crisis refers to the severe problems arising or likely to arise due to climate change.
Since the mid‑19th century, the Earth’s average temperature has risen by 1.1°C, causing significant damage worldwide. Scientists expect that warming above 1.5°C could trigger a series of tipping points, some of which would be irreversible and pose a serious threat to human civilisation.
Climate feedback loops occur when one climate change triggers further changes in a chain reaction that intensifies over time. Feedback loops can eventually trigger tipping points, making climate‑system changes severe and irreversible.
Examples include Arctic sea‑ice melt, which exposes darker ocean water that absorbs more heat, accelerating warming and further melting.
Other loops include permafrost thaw, forest dieback and insect outbreaks.
Tipping point is a threshold beyond which certain changes caused by global warming become irreversible, even if future interventions succeed in lowering temperatures.
Examples include the collapse of the Greenland and West Antarctic ice sheets, thawing of permafrost releasing massive greenhouse‑gas quantities, coral‑reef die‑offs and rainforest destruction.
The Paris Agreement calls on countries to limit warming to well below 2°C and pursue efforts to limit it to 1.5°C. However, even best‑case scenarios now indicate a significant likelihood of temporarily exceeding these limits.
Climate overshoot refers to the period during which warming exceeds 1.5°C before later decreasing. This is expected around mid‑century, though signs suggest it may occur earlier.
Longer overshoot periods increase risks, causing irreversible impacts on ecosystems, biodiversity and human communities, especially in dry regions, coastal zones and other vulnerable areas. Significant emission reductions this decade are crucial to limiting overshoot duration and impacts.
Climate finance refers to financial resources and instruments used to support climate‑action measures. It is essential due to the large investments required for the transition to a low‑carbon global economy and for helping societies build resilience and adapt to climate impacts.
Climate finance can come from public or private, national or international, bilateral or multilateral sources. Instruments include grants, green bonds, debt swaps, guarantees and concessional loans.
Multilateral funds include the Green Climate Fund (GCF), Global Environment Facility (GEF) and Adaptation Fund (AF).
High‑income countries with significant historical emissions have pledged to mobilise USD 100 billion annually for climate action in low‑income countries — a goal not yet achieved.
Rewilding is the large‑scale restoration of ecosystems damaged by human activity. Unlike conservation, which focuses on protecting specific species through targeted intervention, rewilding sets aside large areas for natural regeneration. It sometimes requires reintroducing key species such as beavers, wolves or large herbivores that shape ecosystems.
Rewilding helps combat climate change by removing more CO₂ through natural processes such as forest regeneration and helps prevent species extinction by creating habitats that allow wildlife to adapt and migrate.
Greenwashing refers to misleading claims by companies about their positive environmental impact or sustainability of their products and services, intended to convince consumers they are acting on climate change.
Greenwashing may be unintentional due to lack of knowledge, but it can also be deliberate as a marketing or PR strategy.
It undermines public trust in sustainability and allows harmful environmental impacts to continue.
If you are interested in other terms important to you, write to us at actgreen@zagreb.hr
Sources:
https://climatepromise.undp.org/news-and-stories/climate-dictionary-everyday-guide-climate-change
https://terrapija.terrahub.eu/1.0/galerija/
https://www.eea.europa.eu/help/glossary/eea-glossary
https://mpgi.gov.hr/UserDocsImages/dokumenti/NPOO/ZIKGP_NPOO/Metodologija_UHI.pdf
https://mpgi.gov.hr/pristup-informacijama-16/zakoni-i-ostali-propisi/podrucje-prostornog-uredjenja-3218/3218
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