What if the density of the earth's atmosphere doubled?

Climate change

Stefan Rahmstorf

To person

Ph.D., born 1960; Professor of Ocean Physics at the University of Potsdam, Scientist at the Potsdam Institute for Climate Impact Research (PIK), Telegrafenberg C4, 14473 Potsdam.
Email: [email protected]

The already visible climate change is only a harbinger of much larger changes that will occur if the greenhouse gas concentration continues to rise unchecked.


Do humans change the climate? And if so, how quickly and how strongly? These questions have preoccupied science for over a century. By "global warming" is meant the warming of the global mean temperature, not necessarily warming everywhere on earth.

As early as 1824, Jean-Baptiste Fourier described how trace gases in the atmosphere warm the climate. [1] In the 1860s, the physicist John Tyndall studied the effects of various greenhouse gases, especially water vapor. In 1896, the Swedish Nobel Prize winner Svante Arrhenius calculated for the first time that doubling the carbon dioxide (CO2) content of the atmosphere would lead to a temperature increase of four to six degrees Celsius. In the 1930s, a connection between the global warming observed at the time and the increase in CO2 due to industrialization was discussed in the specialist literature; however, it could not be proven at the time. The danger of anthropogenic (man-made) warming has only been taken seriously since the 1950s. As part of the International Geophysical Year 1957/58, it was possible to prove that the CO2 concentration in the atmosphere actually increases; Isotope analyzes also showed that the increase was caused by carbon from the use of fossil fuels - that is, by humans. First simulation calculations with an atmosphere model in the 1960s showed a temperature increase of two degrees with an assumed doubling of the CO2 concentration; another model gave a value of four degrees Celsius.

In the 1970s, the US National Academy of Sciences warned of global warming. [2] She estimated the effect of doubling CO2 on an increase in temperature of 1.5 to 4.5 degrees. This uncertainty margin has been reduced to two to 4.5 degrees in the past few years. In 1990 the first progress report of the Intergovernmental Panel on Climate Change (IPCC) appeared, others followed in 1996, 2001 and 2007. [3] During this period, the scientific findings have hardened to such an extent that almost all climatologists have now proven that noticeable anthropogenic global warming has been proven or at least consider it highly likely.