Greenhouse gases are gaseous components present in the atmosphere that perform an essential function in maintaining the planet’s energy balance, meaning the balance between the energy the Earth receives from the Sun and the energy it releases back into space.

This balance underpins climate stability. Part of the solar radiation that reaches the Earth is absorbed by the Earth’s surface – oceans, soil, and vegetation – and is then re-emitted as infrared radiation (heat). Greenhouse gases have the ability to absorb and re-emit this radiation, retaining part of the heat in the atmosphere and preventing it from immediately dispersing into space.

In practical terms, the atmosphere behaves like a natural thermal regulation system: without greenhouse gases, the planet would rapidly lose the heat accumulated during the day and the average global temperature would fall to around -18°C, compared with the current approximately +15°C, making life as we know it impossible.

In recent decades, however, this balance has been progressively altered. The increase in greenhouse gas emissions is mainly linked to three major areas:

• energy production and consumption based on fossil fuels, such as coal, oil, and natural gas, used to generate electricity, heat buildings, and power transport;
• energy-intensive industrial activities, such as cement or steel production, which release large quantities of CO₂ during production processes;
• large-scale agriculture and livestock farming, which generate methane (CH₄) and nitrous oxide (N₂O) emissions, for example through ruminant digestion or the use of fertilizers.

This increase has led to a rise in the concentration of greenhouse gases in the atmosphere, amplifying the climate system’s capacity to retain heat and contributing to global warming.

How do greenhouse gases work?

The functioning of greenhouse gases is based on the ability of certain molecules to absorb and re-emit infrared radiation, namely the heat emitted by the Earth’s surface. This property depends on their molecular structure, which allows them to “capture” thermal energy and redistribute it in the atmosphere.

When the Earth’s surface warms up, it emits energy in the form of infrared radiation. Greenhouse gases absorb this energy and re-emit it in all directions, including back towards the surface. This mechanism creates a heat-retention effect that helps keep the planet’s temperature stable.

The process can be described in three operational phases:

1. Entry of solar radiation: solar energy, mainly composed of short waves, passes through the atmosphere almost undisturbed and reaches the Earth’s surface.
2. Absorption and re-emission: the Earth’s surface absorbs this energy and re-emits it as infrared radiation (long waves), namely heat.
3. Interaction with greenhouse gases: greenhouse gases intercept part of this radiation and redistribute it in the atmosphere, helping to retain heat.

What are the main greenhouse gases?

The main greenhouse gases differ in terms of concentration, atmospheric lifetime, and heat-trapping capacity (global warming potential (GWP)*):

* Climate-altering potential (GWP – Global Warming Potential) indicates how much a gas contributes to warming compared with CO₂.

A practical example helps clarify the differences: a methane leak along an energy network can generate a much higher immediate climate impact than the same quantity of CO₂. However, CO₂ continues to accumulate over time, contributing persistently to global warming.

The greenhouse effect

The greenhouse effect is a natural phenomenon and essential for life on Earth, but it becomes critical when altered by rising emissions.

Under equilibrium conditions, the climate system maintains a balance between incoming and outgoing energy. However, when the concentration of greenhouse gases increases, a growing share of energy remains trapped in the system.

This energy surplus is distributed among the atmosphere, oceans, and the Earth’s surface, and manifests itself through concrete and measurable effects:

• increase in average global temperatures, altering seasonality and climate cycles;
• ocean warming, with oceans absorbing more than 90% of excess heat, altering marine ecosystems and currents;
• melting of ice, resulting in sea level rise;
• greater climate variability, with more frequent and intense extreme events.

Observable examples include increasingly frequent heatwaves in Europe or prolonged periods of drought affecting agriculture and water availability.

What are the benefits of reducing greenhouse gases?

Reducing greenhouse gas emissions means acting directly on the planet’s energy balance, limiting the amount of heat retained in the atmosphere.

From an operational perspective, this translates into tangible benefits for economic and infrastructure systems. For example, reducing emissions helps to:

• decrease the exposure of critical infrastructure – such as energy networks or transport systems – to extreme climate events;
• improve climate predictability, facilitating industrial and agricultural planning;
• reduce the economic costs associated with natural disasters, such as floods, wildfires, or droughts.

Environmental benefits and climate change mitigation

Reducing emissions makes it possible to act directly on the dynamics of the climate system.

In practical terms:

• a decrease in emissions slows the rise in average global temperature;
• natural ecosystems, such as forests and oceans, maintain their capacity to absorb CO₂;
• the risk of exceeding critical thresholds (tipping points), beyond which changes become irreversible, is reduced.

A relevant example is the energy transition: replacing coal with natural gas or renewable sources makes it possible to significantly reduce CO₂ emissions per unit of energy produced.

Positive impacts on health and biodiversity

Reducing emissions generates indirect but significant effects on health and the environment.

Many sources of greenhouse gases are in fact associated with harmful air pollutants, such as fine particulate matter and nitrogen oxides. Reducing these emissions improves air quality, with tangible effects on public health, for example by reducing respiratory and cardiovascular diseases.

At the same time, climate stabilization helps to:

• preserve natural habitats;
• reduce pressure on ecosystems;
• protect biodiversity, limiting species loss.

Limits and challenges in reducing greenhouse gases

Reducing emissions requires a profound transformation of energy and industrial systems.

The benefits are clear, but challenges also emerge in relation to the timing and costs of the transition. For example, converting a coal-fired power plant or upgrading industrial facilities requires years, significant investment, and skills development.

The complexity stems from the fact that today’s infrastructure is the result of decades of development and cannot be changed rapidly without operational and economic impacts.

Technological and industrial challenges

Some sectors – such as heavy industry and transport – face greater difficulties in reducing emissions, (the so-called hard-to-abate sectors).

The main challenges concern:

• the development of innovative technologies, such as hydrogen or CO₂ capture and storage systems;
• the upgrading of existing infrastructure;
• the integration of increasingly complex energy systems.

For example, the introduction of hydrogen requires not only sustainable production, but also compatible networks and adequate safety systems.

Global action and international cooperation

Climate change is a global phenomenon and requires coordinated responses.

Emissions produced in one country affect the entire planet. For this reason, reducing greenhouse gases requires:
• shared international agreements;
• coordinated policies among States;
• common emission-reduction targets.

International cooperation is therefore a necessary condition for achieving effective and lasting results.

The future of greenhouse gas reduction

The future of emission reduction depends on the ability to integrate sustainability, innovation, and economic development.

The energy transition is not a linear process, but a pathway that requires:

• long-term planning;
• structural investment;
• continuous technological evolution.

The goal is to build energy systems capable of ensuring security, sustainability, and competitiveness.

Technological innovations in decarbonization

Decarbonization is based on a set of innovations that are transforming the energy sector.

Among the main levers:

• digitalization of networks, enabling real-time monitoring, loss reduction, and greater operational efficiency;
• energy efficiency, making it possible to reduce consumption and emissions;
• integration of renewable gases, such as biomethane and hydrogen, into existing infrastructure.

A concrete example is the injection of biomethane into gas networks: it allows emissions to be reduced without modifying domestic or industrial systems, while maintaining operational continuity.

Overall, reducing greenhouse gases represents a systemic challenge that requires an integrated approach involving technology, public policies, and investment, with the aim of building a sustainable and resilient development model over the long term.