Does climate change have a timescale

Climate change is not a modern phenomenon

Interaction between oceans and atmosphere

The interdisciplinary research on climate and weather phenomena, which has been intensified over the last few decades, has made the importance of the interaction between oceans and atmosphere ever clearer. This is shown, for example, by the El Niño phenomenon, an event in which changes in the surface waters of the Pacific shape the climate of the adjacent continents. Droughts in northeast Australia or heavy rain events on the west coast of South America can be explained in this way, even if they cannot (yet) be forecast.

How does it look in the future?

The climate will continue to change in the future, because both Greenland and Antarctica will still need some time (viewed in geological time dimensions) to drift back towards the lower latitudes (a map of this is e.g. on the page "Paleomap Project"). And since the warm periods are the significantly shorter sections compared to the cold periods and the climatic optimum of the current warm period (Holocene) has already been exceeded, we are looking forward to a new cold period. However, according to the analysis of ice cores from the Antarctic by scientists from the Alfred Wegener Institute, this will still be around 15,000 years away. The question remains whether the anthropogenic climate impact will remain constant, diminished or even become more significant.

Importance of the topic of climatic fluctuations in the history of the earth in geography lessons

First of all, rightly the question arises why it is helpful to acquire knowledge about the climate of prehistoric times: Firstly, they help to better understand our planet and above all the development of life on earth. This enables us to better assess the current problems, for example with regard to the food supply for the world's population. Second, knowledge of the prehistoric climate helps in looking into the future of the earth's climate. The climate is not subject to any absolute regularities that enable exact forecasts or even predictions. Nevertheless, research over the last few decades shows that we can develop ever more precise forecasts due to increasing detailed knowledge of the prehistoric climate.

The greatest unknown is the person who “turns the wheel” and currently reinforces a trend towards a slight increase in temperature due to the natural rhythm by affecting the current earth climate.

The aim is not to trivialize the anthropogenic greenhouse effect, but it is imperative to understand the climate of the earth's history - also in different time dimensions - in order to arrive at an objective assessment of the problem area “climate change”.

Methodical implementation

The entry takes place via the animation “Mediterranean isolation and desiccation during the Messinian Salinity Crisis” on Youtube, which illustrates the drying up of the Mediterranean around 5.5 million years ago. Following on from this, the question can be asked what the conditions were ultimately for the drying out and what consequences this process had for the climate in today's Mediterranean area.

The students then describe the climate development over the past 600 million years. There are suitable graphics, for example, in the book "Climate: The earth and its atmosphere in the course of time" by Christoph Buchal and Christian-Dietrich Schönwiese. It is a good idea to have a timeline created. The carbon dioxide content of the atmosphere over the course of the earth's history can also be viewed. Then the climate development in the Ice Age should be examined more closely.