The global climate has always fluctuated to a greater or lesser extent, caused by various natural processes. In general, four different parameters can be named that cause the global climate to fluctuate:
- Changes in incident solar radiation
- Changes in reflected solar radiation
- Changes in thermal radiation emitted into space
- Internal fluctuations of the climate system
Recurrent changes in the Earth's orbit can be detected at regular, very large intervals of several tens of thousands of years, with high correlations documented with climatic changes on Earth. Likewise, the activity and thus the radiation of the sun arriving on Earth vary. The position of the continents directly affects the air and ocean circulations and thus also the global climate. And volcanic eruptions also emit large quantities of CO₂, probably the best-known greenhouse gas, but also aerosols, volcanic ash and dust particles, ultimately resulting in a temporary cooling of the climate over one to two years.
Anthropogenic climate change
The average global surface temperature has increased by 1.04 °C in the last 130 years, an unusually rapid increase. In particular, according to the scientific reports of the Intergovernmental Panel on Climate Change (IPCC), the sharp increase in global warming since 1950 can no longer be explained by natural climate fluctuations. Greenhouse gases such as carbon dioxide (CO₂) are almost certainly responsible for this. Since industrialisation, these gases have been increasingly released into the atmosphere through the burning of fossil fuels such as coal, oil and natural gas, as well as through large-scale land use, such as the deforestation of tropical rainforests, and have intensified their greenhouse effect.
Global warming - a chain reaction
Rising air and ocean temperatures are gradually reducing the total global snow and ice mass. As a result of this, but also due to the increase in the volume of water with rising temperatures, sea levels are also rising. In addition, global warming increases the probability of extreme weather events with far-reaching impacts on humans and the environment.
Sources: Federal Office of the Environment (FOEN) 2017; IPCC 2018, Special Report Global Warming of 1.5º C; FAU Florida Atlantic University 2018