Greenhouse gases: what they are, impact, and how they are measured

While the concentration of carbon dioxide (CO2) in the atmosphere has been steadily and rapidly increasing in recent decades, in May 2025, CO2 surpassed 430 parts per million (ppm) for the first time, setting a new historical record.

This milestone, recorded at the Mauna Loa Observatory (Hawaii), confirms the acceleration of climate change and highlights the urgency of understanding its causes: greenhouse gases, with CO2 being one of the most potent and well-known.

This article analyses what greenhouse gases are and how their accumulation in the atmosphere is transforming living conditions on the planet by driving global warming. It also explores how to keep them under control through accurate detection and measurement of their presence in the atmosphere.

What are greenhouse gases (GHGs)?

Definition and natural function of GHGs

Greenhouse gases (GHGs) are gaseous components present in the atmosphere, originating both naturally and artificially (mainly from anthropogenic activities). Their main characteristic is their ability to absorb and emit infrared radiation. This is an essential physical process for the Earth’s climate system, as it retains part of the heat that reaches the planet’s surface, preventing it from escaping entirely into space, thus enabling life on Earth. This natural phenomenon is called the ‘greenhouse effect’ and is vital for the survival of living beings.

However, since the Industrial Revolution, human activity has significantly increased the concentration of these gases in the atmosphere, enhancing the greenhouse effect and intensifying global warming, thereby altering the natural climate balance.

The main GHGs include carbon dioxide (CO₂)Carbon dioxide (CO2) is a gas that occurs naturally in the atmosphere and plays a crucial role in the life processes of the planet. This gas, also known as...
Read more, methane (CH₄)Methane, known chemically as CH₄, is a gas that is harmful to the atmosphere and to living beings because it has a high heat-trapping capacity. For this ...
Read more, nitrous oxide (N₂O), tropospheric ozoneTropospheric ozone (O3) or ground-level ozone is a gas found in the lowest layer of the Earth's atmosphere, the troposphere, which extends up to 10 kilomet...
Read more (O₃), fluorinated gases such as hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs), sulphur hexafluoride (SF₆), and water vapour.

Main emission sources

The main anthropogenic activities that are sources of GHG emissions include:

• Burning of fossil fuels: The use of coal, oil, and natural gas for electricity generation, transport, and industry results in large emissions of CO₂ and, to a lesser extent, N₂O, as we analysed in this article.
• Deforestation and land use change: The clearing of forests for agriculture or logging reduces the crucial role of trees in absorbing atmospheric CO₂; tree felling also releases stored carbon into the atmosphere.
• Livestock farming: The raising of cattle and sheep produces significant CH4 emissions from digestion (enteric fermentation) and manure management.
• Intensive agriculture: The use of nitrogen fertilisers generates N₂O emissions, one of the most potent GHGs.
• Industry: GHGs are commonly emitted during the production of chemicals, cement, and steel; manufacturing processes also release fluorinated gases.
• Landfills: Waste management and wastewater treatment plants generate organic residues whose anaerobic degradation produces, among others, CH₄ emissions.

impact of greenhouse gases on the environment and health

Climate change and environmental consequences

The natural regulatory function of GHGs in the atmosphere has been disrupted by increased concentrations due to human activities. This has led to a rise in global temperature, as energy accumulates in the troposphere, causing a wide range of interconnected environmental effects. These alter ecosystems and threaten human health and well-being through:

• Increased frequency of extreme weather events (heatwaves, droughts, heavy rainfall, hurricanes) leading to higher direct mortality.
• Disruption of cryospheric and oceanic dynamics due to high emissions, causing polar ice melt, ocean acidification, and sea level rise.
• Disturbance of ecosystems, forcing terrestrial species to migrate in search of new climatic niches; loss of biodiversity; trophic collapse due to broken biological cycles and food chains; and water stress in regions like the Mediterranean due to reduced rainfall and increased evapotranspiration.

Effects on public health

Although GHGs are not toxic at usual concentrations, their atmospheric increase and role in accelerating climate change are causing concerning health consequences:

• Higher risk of respiratory and cardiovascular diseases due to the direct link between rising temperatures and declining air qualityAir quality refers to the state of the air we breathe and its composition in terms of pollutants present in the atmosphere. It is considered good when poll...
  Read more.
• Increase in vector-borne diseases as temperatures rise.
• Heat stress from extreme heat, especially affecting vulnerable populations and those with comorbidities.
• Food insecurity due to reduced crop yields and the resulting risk of malnutrition and famine.

International regulation and commitments on GHGs

The Paris Agreement and global objectives

Regulating and managing GHGs globally is fundamental to mitigating climate change. The main international instrument for coordinating global efforts is the Paris Agreement. Legally binding, it was adopted in 2015 during the 21st Conference of the Parties (COP21) of the United Nations Framework Convention on Climate Change, aiming to limit the increase in global average temperature to well below 2°C, with the aspiration not to exceed 1.5°C above pre-industrial levels.

 

The agreement is characterised by its approach based on voluntary national commitments. Each member country must submit, update, and periodically improve (every 5 years) its Nationally Determined Contributions (NDCs), detailing concrete actions and GHG reduction targets to be achieved within set timeframes. Implementing and meeting the NDCs is essential for assessing collective progress towards the global goal, as they cover both emission mitigation and adaptation to climate change effects.

The Agreement aims to reach peak GHG emissions as soon as possible so that the planet can achieve climate neutrality by 2050. This relies on transparency and international cooperation, the exchange of clean technologies, and financial support for developing countries. In this way, it seeks to ensure that all states, regardless of their economic development level, can contribute fairly and effectively to emission reduction and climate protection. This international framework not only sets ambitious targets but also promotes shared responsibility and technological innovation as essential pillars for a more sustainable future.

 

Legislation and applicable limits in the eu and other regions

GHG regulation in the EU and other regions has been strengthened in recent years, establishing legal limits and mechanisms to reduce atmospheric emissionsAtmospheric emissions are pollutants emitted into the air, mainly as a result of human activities such as industry, transport by combustion vehicles and en...
Read more and promote sustainability.

In the European Union, the European Green Deal underpins the priority strategy to transform the economy and society towards climate neutrality, i.e., achieving net zero GHG emissions by 2050. This means only emitting gases that nature (forests, oceans, and soils) can absorb. To achieve this, the EU has several key instruments:

• Emissions Trading System (EU ETS): A system that limits the total amount of emissions allowed for certain industrial sectors. It allows trading of emission rights to incentivise the reduction of polluting gases and investment in clean technologies.
• EU Climate Law: Makes the climate neutrality target legally binding and requires Member States to adopt policies and measures to reduce GHG emissions by at least 55% by 2030 compared to 1990 levels.
• ‘Fit for 55’ legislative package: Measures to update climate, energy, transport, and energy efficiency legislation, aligning current rules with the EU’s climate objectives.

In the United States, the Environmental Protection Agency (EPA) is responsible for regulating GHG emissions through specific regulations that set emission limits for power plants, vehicles, and industries. These regulations aim to reduce air pollution and move towards a low-carbon economy.

There are also international standards and voluntary frameworks that drive environmental management in the private sector, supported by:

• ISO standards: Standards such as ISO 14001 help companies implement environmental management systems and monitor and reduce GHG emissions.
• ESG frameworks (Environmental, Social, and Governance): Promote transparency and environmental responsibility in companies, requiring measurement, control, and reduction of emissions, as well as the adoption of sustainable practices.

Together, these laws and regulatory frameworks aim to limit the impact of GHGs from human activities on the climate, foster technological innovation, and ensure a just transition to a decarbonised and sustainable economy.

How greenhouse gases are measured

Greenhouse gas measurement technologies

Accurate measurement of greenhouse gases (GHGs) is a fundamental task that allows understanding their dynamics, assessing their environmental impact, and most importantly, designing effective mitigation strategies. To achieve this, various technologies are used to detect and quantify their concentrations.

• Non-dispersive infrared absorption spectroscopy (NDIR): This is the most commonly used technology for GHGs such as CO₂ and CH₄ and is based on the selective absorption of infrared radiation by specific molecules. It is commonly applied in portable analysers and continuous monitoring systems due to its high sensitivity and fast detection.
• Electrochemical and photoacoustic sensors: Used for gases such as NO₂ and O₃, these sensors convert chemical or acoustic interactions into electrical signals, offering high sensitivity and the possibility of integration into wireless networks for extensive monitoring.
• Laser technologies (TDLAS, CRDS): High-precision systems used in industrial environments based on techniques such as Tunable Diode Laser Absorption Spectroscopy (TDLAS) and Cavity Ring-Down Spectroscopy (CRDS). They provide highly accurate and specific measurements, ideal for industrial and agricultural settings where rigorous emission control is required.
• Gas chromatography (GC): A technique that separates and quantifies gaseous components of the atmosphere, enabling detailed analysis of complex GHG mixtures. It is particularly useful in laboratories and for validating field data.

Greenhouse gas monitoring platforms

These techniques are deployed across various monitoring platforms:

• Fixed and mobile stations: Equipped with the sensors mentioned, these stations enable continuous GHG monitoring in outdoor and indoor environments, facilitating the evaluation of temporal and spatial trends.
• Portable systems and soil chambers: Use tools such as portable FTIR analysers and soil flux chambers to measure direct emissions on site, capturing the spatial and temporal variability of GHGs in different environments.
• Wireless sensor networks: By integrating photoacoustic technologies with wireless communications, these networks create extensive and accessible monitoring systems capable of collecting large amounts of real-time data.
• Satellite monitoring: Complements ground measurements through high-resolution spectrometers and LIDAR systems that detect and quantify GHGs from Earth’s orbit.

Together, these technologies form a comprehensive instrumental suite that, through the combination of methods and platforms, enables detailed and reliable monitoring of greenhouse gases, which is key for decision-making in climate policy and environmental management of GHGs.

The importance of continuous monitoring

Continuous GHG monitoring is an essential tool for environmental management, both industrially and urbanly. Having real-time data allows a prompt and informed response to climate challenges, optimising environmental performance and facilitating the achievement of sustainability goals.

In the industrial sector, constant monitoring enables immediate detection of leaks or emission spikes, reducing environmental impact and improving operational safety. Additionally, it makes possible the optimisation of industrial and energy processes, as precise emissions data helps identify critical industrial points and develop improvement opportunities.

In regulatory terms, continuous monitoring is essential to comply with environmental regulations. Authorities can verify adherence to emission limits and demand corrective actions, if necessary, to protect the environment and public health.

Finally, the information generated by these monitoring systems is fundamental for making strategic decisions in sustainability and for reducing the carbon footprintIn a world increasingly affected by climate change, understanding how our everyday actions contribute to its worsening has become essential. The carbon foo...
Read more. Cities and companies can prioritise investments in clean technologies, plan mitigation and adaptation policies, and transparently communicate their progress in combating climate change based on this data.

In summary, continuous GHG monitoring not only improves environmental management and regulatory compliance but also drives innovation and social responsibility, increasingly valued in climate action.

Practical applications and sectors requiring GHG measurement

Greenhouse gas (GHG) measurement has essential practical applications across various strategic sectors, enabling emission control, process optimisation, and regulatory compliance.

The following productive sectors, due to their environmental impact and significant contribution to climate change, require advanced and continuous monitoring systems:

• Refineries and chemical plants: Industrial environments where GHG measurement is critical for leak detection, combustion process control, and strict compliance with environmental regulations. Real-time monitoring allows identification of emission points and facilitates corrective measures, contributing to energy efficiency and carbon footprint reduction.
• Landfills and waste treatment: The decomposition of organic matter in landfills and waste treatment plants generates a potent GHG such as methane. Measuring and capturing this atmospheric gas not only mitigates climate impact but can also be harnessed for renewable energy generation through biogas production.
• Intensive agriculture and livestock farming: Activities that are major sources of GHG emissions, primarily methane and nitrous oxide. Monitoring enables quantification of these emissions, assessment of different agricultural practices’ impacts, and development of mitigation strategies such as improved manure management and optimised fertiliser use.
• Cities and metropolitan areas: Populated environments are major GHG emitters due to transport, industry, and energy consumption. Continuous measurement helps identify emission sources, evaluate urban policy effectiveness, and guide planning towards sustainability and improved air quality.
• Maritime, air, and land transport: This sector is a significant contributor to global GHG emissions. Monitoring supports impact assessment of different technologies and fuels and ensures compliance with international and local decarbonisation regulations.

In all these sectors, GHG measurement is key to advancing the transition towards a low-carbon economy and meeting international climate commitments.

Greenhouse gas monitoring solutions

Kunak’s GHG measurement systems represent an advanced technological solution designed to meet environmental monitoring needs in both industrial and urban settings.

Advantages of Kunak’s GHG measurement systems

The design and functionality, along with the cost-effectiveness of Kunak’s GHG measurement systems, provide multiple practical and technical benefits for managing and controlling atmospheric emissions. Key advantages of Kunak solutions include:

• Continuous, high temporal resolution monitoring: Captures real-time data at high frequency, essential for promptly detecting anomalies, emission spikes, or pollution trends, enabling immediate decision-making and alignment with environmental policies.
• Interchangeable and calibratable sensors: A broad range of sensors adaptable to different atmospheric gases and particulate matter. Easy calibration ensures measurement accuracy and reliability over time.
• Remote management via cloud platforms: Integrated with digital platforms that provide remote data access, real-time visualisation, and advanced analytics from any location, optimising system management and maintenance.
• Easy integration into environmental control networks: Kunak devices connect seamlessly to existing monitoring systems, facilitating interoperability and creating extensive, flexible sensor networks in both cities and industrial complexes.
• Robust and compact design: Engineered to withstand harsh environmental conditions and operate in confined spaces, ideal for deployment in demanding settings such as factories, refineries, or urban areas.

Consequently, these features make Kunak systems essential tools for measuring, researching, and sustainably managing urban and industrial environments, providing reliable and accessible data that supports climate change understanding and compliance with international GHG agreements.

Examples of gases measurable with Kunak AIR

Kunak AIR stations excel in measuring a wide range of greenhouse gases and atmospheric pollutants, making them indispensable tools for environmental monitoring in urban and industrial contexts. Their modularity—enabled by the patented cartridge system—and versatility allow equipping them with specific sensors for each requirement, ensuring precise and reliable data collection tailored to each scenario.

Among the gases and particles measurable with Kunak AIR systems are:

• Carbon dioxide (CO₂): the principal greenhouse gas, key to assessing the contribution of fixed and mobile sources to climate change.
• Methane (CH₄): a potent GHG produced in landfills, livestock operations, and industrial processes; monitoring helps identify leaks and reduce emissions.
• Nitrogen oxides (NO₂): a pollutant associated with traffic and industry, significant both for its climate impact and effects on air quality and human health.
• Tropospheric ozone (O₃): an atmospheric gas acting as a secondary pollutant, highly harmful to health.
• Volatile organic compounds (VOCs): emitted by industrial activities, fossil fuel combustion, and chemical use, their measurement is critical for air quality control.
• Particulate matter (PM₁, PM_2,5, PM₄, PM₁₀): linked to combustion processes and industrial activities, these particles have a direct impact on respiratory and cardiovascular health, and contribute to aerosol formation affecting climate conditions.

The ability to integrate sensors measuring all these pollutants in a single platform enables comprehensive air quality management, facilitating source identification, regulatory compliance, and informed decision-making on sustainability and public health. This multi-pollutant monitoring capability is especially relevant for reducing GHGs to mitigate climate change.

Frequently asked questions about greenhouse gases

What gases are considered greenhouse gases?

Greenhouse gases (GHGs) are gaseous compounds that have the ability to absorb and emit solar infrared radiation, trapping some of the heat the Earth emits into space. This phenomenon, known as the greenhouse effect, is fundamental to maintaining the planet’s temperature at habitable levels, but its intensification due to human activity is causing the acceleration of global warming. Collectively, these gases regulate Earth’s climate, but the increase in their concentrations from human activity is disrupting the natural balance, leading to widespread environmental and climatic consequences.

The main greenhouse gases identified in the Earth’s atmosphere are:

• Carbon dioxide (CO₂): the most abundant GHG resulting from human activity and the primary driver of current climate change. It is mainly produced by fossil fuel combustion, deforestation, and industrial processes.
• Methane (CH₄): much more potent than CO₂ in terms of heat retention, although present in much lower concentrations. Its main sources include livestock, landfills, and fossil fuel extraction.
• Nitrous oxide (N₂O): with a very high global warming potential and a long atmospheric lifetime. It is mainly generated from nitrogen fertiliser use in agriculture and industrial processes.
• Tropospheric ozone (O₃): unlike stratospheric ozone (which protects us from solar ultraviolet radiation), tropospheric ozone acts as a GHG, forming from chemical reactions among atmospheric pollutants.
• Water vapour (H₂O): the most abundant natural GHG, significantly contributing to the greenhouse effect, though its concentration depends on climate and is not directly controlled by human activity.
• Fluorinated industrial gases (HFCs, PFCs, SF₆, NF₃): synthetic compounds used in refrigeration, air conditioning, and industrial processes with extremely high global warming potential, though present in low atmospheric concentrations.

What is the most abundant greenhouse gas?

Carbon dioxide (CO₂) is the most abundant greenhouse gas in the atmosphere and the greatest contributor to global warming, primarily due to its high volume of emissions associated with human activity, such as fossil fuel burning, cement production, and deforestation.

Although its atmospheric concentration is relatively low compared to other major gases in the atmosphere, CO₂ is responsible for approximately 66% of the global warming effect attributed to greenhouse gases. Its ability to remain in the atmosphere for thousands of years and its progressive accumulation since the Industrial Revolution have made CO₂ the primary driver of climate change.

Therefore, CO₂ stands out not only for its abundance among greenhouse gases but also for its significant impact on global warming and the need to measure and control its emissions to mitigate climate change.

How can greenhouse gas emissions be reduced?

Reducing GHG emissions is vital to protect the planet’s living conditions and ensure a sustainable future for all living beings. To achieve this, it is necessary to invest in renewable energies such as solar, wind, hydroelectric, and nuclear power, which do not rely on fossil fuels and generate less atmospheric pollution. Additionally, improving energy efficiency in homes, industries, and cities is also recommended to optimise resources and reduce energy waste.

Transport plays a crucial role in strategies to reduce GHG emissions. Promoting sustainable transport such as electric vehicles, bicycles, and public transport reduces environmental impact and dependence on polluting fuels. Likewise, nature-based solutions are essential: reforestation and ecosystem conservation help capture carbon from the atmosphere and maintain climate balance.

In summary, a combination of clean technologies, responsible behaviours, and respect for nature is the key to reducing GHG emissions and moving towards a more habitable and balanced world.

How are greenhouse gases measured?

Precise measurement of greenhouse gases (GHGs) is essential to understand their behaviour in the atmosphere, assess their impact on the environment, and design effective strategies to mitigate their effect on climate change. To achieve these measurements, various advanced technologies are used:

• Infrared absorption spectroscopy (NDIR): particularly useful for gases such as CO₂ and CH₄, it uses infrared radiation absorption and is employed in portable analysers and continuous monitoring systems due to its sensitivity and speed.
• Electrochemical and photoacoustic sensors: detect compounds like NO₂ and O₃ by converting chemical or acoustic interactions into electrical signals, enabling integration into wireless monitoring networks.
• Laser technologies (TDLAS, CRDS): provide high precision and specificity measurements, ideal for industrial and agricultural environments where emission control is critical.
• Gas chromatography (GC): allows analysis of complex GHG mixtures, fundamental in laboratories and for field data validation.

These techniques are implemented through various platforms, including fixed and mobile stations, portable systems, wireless sensor networks, and satellite monitoring, enabling continuous and comprehensive surveillance at local and global levels. The combination of these methods ensures reliable and detailed GHG tracking, key for decision-making in climate policy and environmental management.

Why is it important to control GHG emissions?

Controlling greenhouse gas (GHG) emissions is crucial because these gases are directly linked to global warming. When human activities increase their presence in the atmosphere—especially carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O)—the natural climate balance is disrupted, causing global temperatures to rise and climate patterns to change.

This increase in gases intensifies the greenhouse effect, trapping more heat in the atmosphere and causing extreme weather events such as heatwaves, droughts, floods, and stronger storms. It also contributes to rising sea levels and ocean acidification. Moreover, pollution from burning fossil fuels impacts health by increasing respiratory and cardiovascular problems and hindering access to safe food.

Conclusion

The urgency of combating climate change has placed the need to understand and limit greenhouse gas emissions at the centre of the global debate. These gases are responsible for profound alterations in climate patterns, causing issues in human health and ecosystems. In this context, having accurate and reliable tools is not just a technological advantage but an essential condition to move towards effective action.

Kunak stations represent an essential advance in practical management of global warming. Their ability to measure powerful GHGs like CO₂, CH₄, N₂O, O₃, volatile organic compounds, and particulate matter continuously and in real time allows industries, governments, and environmental experts to identify leaks, optimise processes, and comply with regulations proactively.

This comprehensive monitoring is the foundation for building emission reduction and climate adaptation strategies, enabling a just transition towards more sustainable and resilient economies.

Monitoring is not just observation; it is the first decisive step to intervene, innovate, and transform. Kunak’s robust and adaptable technology thus becomes an indispensable ally for immediate action and tangible results, as well as responsible anticipation of climate challenges.