Allow us to explain this phenomenon systemically: The Earth’s surface is warmed by solar radiation. The earth's surface reflects the radiation as long-wave heat radiation, which is partially absorbed by the atmospheric greenhouse gases. By subsequently emitting the absorbed energy, part of the radiation is reflected back to the earth and the earth's surface and lower atmospheric layers are heated. This process is referred to as the greenhouse effect.
The natural greenhouse gas effect
The natural greenhouse effect makes life on earth possible, as it has developed to this day. Based on the natural presence of greenhouse gases, water vapour and carbon dioxide, there is a temperature difference of 33° according to the current state of research. This means that without greenhouse gases, the average temperature on Earth would be around -18° C and the earth and life on it would never have developed as we know it today.
The man-made greenhouse gas effect
However, the natural balance between irradiation and radiation is disturbed by the greenhouse gases caused by humans. Since the beginning of industrialisation, emissions of greenhouse gases such as carbon dioxide (CO₂), methane and nitrous oxide have risen dramatically. Today, 40% more CO₂ exists in the atmosphere than at the beginning of the industrial age. This means the temperature of the earth's surface has increased globally by 0.85°C since the beginning of the 20th century.
Sources: Federal office for the Environment (FOEN) 2018; German Environment Agency (UBA) 2017; IPCC 2013 Assessment Report 5; IPCC 2007 Glossary