Attempt at a Synopsis (Global Syntheses)

The factors influencing climate in the Quaternary are not comparable to the present and are therefore not a key to climate development in the future. The solar radiation budget has significantly influenced the warming since AD 1850, but aerosols, greenhouse gases, anthropogenically induced albedo changes and much more will strongly shape the natural climate development in the future. Therefore, a prediction for the climate future based on past conditions remains hypothetical. For this reason, numerous research results are presented in the chapters on the ice age (Chap. 2 ), on the tropics (Chap. 3 ) and on the climate archives (Chap. 4 ), showing the possibilities and limitations of climate modelling in the future. At present, it is not possible to state what influence humans have had on climate development over the last millennia, centuries and decades. What is certain is that anthropogenic forcings are very diverse. New knowledge about the influence of individual parameters (aerosols, solar wind, clouds, etc.) on the terrestrial climate is constantly being gained. It is therefore not possible to quantify anthropogenic and natural climate forcings with sufficient precision to take concrete measures to influence the global climate (reduction of global warming to ≤2 °C since AD 1850), as called for by the World Climate Conference. The future will show whether the increase in CO2atm levels can be reduced (without further drastic measures) and thereby achieve the desired success. For the time being, humankind must prepare for further global warming, with all its “side effects” (sea-level rise, shifting and qualitative changes in climate and landscape zones, etc.).