Home / Press review / Archive / Magazine / Society / Climate / Background

Human influence on the climate

Carbon dioxide levels in the atmosphere have not been this high for thousands of years. There is no doubt that mankind is partly responsible. A brief description of the greenhouse effect and its consequences.

With weather extremes on the rise all over the world over the past decades, the climate has become a major issue in the public eye. For instance, the year 2005 was not only the warmest since temperatures have been recorded but it also featured the highest number of hurricanes and the lowest extent of Arctic sea ice ever.

Carbon dioxide levels have increased rapidly since industrialisation began.
Photo: Photocase.com

There is hardly any doubt that humans impact global climate. As a result of this impact, global warming will continue to increase in the decades to come. In a warmer world, more water can evaporate, which may further intensify individual climatological phenomena. Consequently, the question arises as to what extent the increase in extreme weather events we currently observe, such as heavy rainfall in Germany or the increases in the frequency and intensity of tropical cyclones (such as hurricanes and typhoons) are already signs of global warming.

The cause for the climate change can be traced back to human activities that release certain climate-changing trace gases into the atmosphere. These gases further warm the earth's surface and the lower atmosphere producing an anthropogenic greenhouse effect. Carbon dioxide (CO2) is paramount in this development. It is primarily emitted into the atmosphere as a result of burning fossil fuels (oil, coal, natural gas). Global CO2 emissions are closely linked to the world's energy consumption as energy generation mostly relies on fossil energy sources. Other important trace gases include methane (CH4), nitrous dioxide (N2O) and chlorofluorocarbons (CFCs). Carbon dioxide is responsible for about 50% of the greenhouse effect caused by humans. Emitted into the atmosphere as a result of human activity, it typically remains there for a century which illustrates the long-term nature of the climate issue.

For hundreds of thousands of years the CO2 concentration in the Earth's atmosphere has not been as high as today. Measurements clearly show that the concentration of CO2 in the atmosphere has sky-rocketed since the beginning of the Industrial Revolution. Whereas CO2 content was at about 280 ppm (parts per million) around 1800, it has reached nearly 380 ppm by now. Nobody can seriously contest that humans are not responsible for this increase. Observing the geological record, one comes to the conclusion that the concentration of CO2 is now higher than it has been in the last 450 000 years (see Figure 1). Scientists have reconstructed the variations in the atmosphere's chemical composition by analysing air bubbles trapped in Antarctic ice cores.

1 . 2 . 3 . 4 . next »

Further articles on the subject » Environmental Policy, » EU Policy, » Global
More from the press review on the subject » Environmental Policy, » EU Policy, » Global