Are humans causing global warming

20 years of Chernobyl

Mojib Latif

To person

Dr. rer. nat., born 1954; Professor of Meteorology at the Leibniz Institute for Marine Sciences (IFM-GEOMAR) at the University of Kiel. D├╝sternbrooker Weg 20, 24105 Kiel.
Email: [email protected]
Internet: www.ifm-geomar.de

The CO2 content of the earth's atmosphere has not been as high as it is today for thousands of years. It can no longer be seriously denied that humans are responsible for this increase.

introduction

The increasing number of weather extremes throughout the world over the past decades have brought the climate problem into the focus of public interest. 2005 was not only the warmest year since there were direct temperature measurements, but also the year with the most hurricanes and the smallest Arctic ice extent.

There is hardly any doubt that humans exert an influence on the global climate and that the global climate will continue to warm as a result of this influence over the next few decades. In a warmer world, more water can evaporate, which can intensify individual weather phenomena. The question arises to what extent the increase in weather extremes that can already be observed today, for example heavy precipitation in Germany or the accumulation and intensification of tropical cyclones (hurricanes, typhoons), are signs of global warming.

The climate problem has its origin in the fact that humans release certain climate-relevant trace gases into the atmosphere through their diverse activities. These lead to additional warming of the earth's surface and the lower air layers, the "anthropogenic" greenhouse effect caused by humans. Of great importance here is carbon dioxide (CO2), which escapes into the atmosphere primarily through the combustion of fossil fuels (crude oil, coal, natural gas). Global CO2 emissions are closely linked to global energy consumption, as energy generation is primarily based on fossil fuels. Other important trace gases are mainly methane (CH4), nitrous oxide (N2O) and the fluorochlorine hydrocarbons (CFC). Carbon dioxide accounts for around 50 percent of the human-made greenhouse effect. CO2 emitted into the atmosphere by humans has a typical retention time of around 100 years, which illustrates the long-term nature of the climate problem.

The CO2 content of the earth's atmosphere has not been as high as it is today for thousands of years. Measurements clearly show that the concentration of CO2 in the atmosphere has increased rapidly since the beginning of the industrial revolution. While the CO2 content around 1800 was around 280 ppm (parts per million), it is now almost 380 ppm. It can no longer be seriously denied that humans are responsible for this increase. A look into the past shows that the CO2 content is already higher than it has been for around 450,000 years (see Figure 1 of the PDF version). The fluctuations in the chemical composition of the earth's atmosphere were reconstructed from ice cores in the Antarctic by analyzing the air bubbles trapped in the ice.