Global warming is one of the most widely used concepts in the context of climate change. It refers to the sustained rise in the average air temperature worldwide relative to a given observation period. The primary cause of the acceleration of these changes is human industrial activity, which has led to significant warming of the land, oceans and atmosphere.

The key mechanism responsible for the rise in temperature on Earth is the greenhouse effect. In its natural form, it plays an extremely important role in sustaining life on our planet. It is the phenomenon that enables the Earth to retain part of the solar energy received, thereby maintaining a stable, life-supporting temperature. How does it work?

Diagram showing how the greenhouse effect works

1. Solar radiation: The Sun emits radiation that reaches the Earth. Part of this radiation is absorbed by the Earth’s surface, while part is reflected back into space.
   
2. Reflection and absorption of heat: Solar energy absorbed by the Earth’s surface causes it to heat up. The warmed surface emits infrared radiation (heat) back towards the atmosphere.
   
3. Greenhouse gases: The atmosphere contains greenhouse gases such as carbon dioxide (CO₂), methane (CH₄), water vapour (H₂O), nitrogen oxides (NOₓ), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulphur hexafluoride (SF₆), which absorb part of the infrared radiation and trap it in the atmosphere, raising the temperature.
   
4. Re-emission of heat: After absorbing the energy, greenhouse gases re-emit it in all directions, including back towards the Earth, which further increases its warming.

The natural greenhouse effect is essential for life on Earth — without it, the average temperature of the planet would be approximately -18°C, making life as we know it impossible. The problem arises when human activity — such as the burning of fossil fuels, deforestation or the emission of refrigerants — leads to an increase in the concentration of greenhouse gases in the atmosphere. As a result, more heat is trapped, leading to global warming and the associated climate changes. According to the IPCC report, in the period 2011–2020 the average global temperature was 1.09 degrees Celsius higher than in the period 1850–1900 (regarded as equivalent to the pre-industrial temperature), with land temperatures rising by 1.59°C and ocean temperatures by 0.88°C. According to the WMO report, the probability that at least one year in the period 2023–2027 will have an average temperature 1.5 degrees higher than the pre-industrial average (1850–1900) is 66%.

Human activity — particularly in industry, transport and agriculture — is today affecting the natural environment in an unprecedented manner. The visible consequences include extreme weather events, rising sea levels and increasingly frequent heatwaves. These changes underscore the necessity of applying the principles of sustainable development in order to counteract the further negative effects of global warming.