The steam that makes the climate in Europe heat up

The steam, not CO2 in the atmosphere, is the main reason why the climate in Europe is getting warmer - according to a study by the World Radiation Center in Davos (Switzerland) published in the journal. Geophysics.

A research group led by Dr. Rolf Philipona uses research networks and meteorological stations across Europe to measure temperature, humidity and long-wave radiation - playing a major role in the greenhouse effect. Observing results from 1995 to 2002 showed that the amount of long-wave radiation towards Earth in Europe increased significantly while solar radiation did not. Long-wave radiation originates from gas molecules such as CO2, methane and steam (absorbing solar radiation after radiation comes into contact with the Earth's surface and reflects back to the atmosphere). The researchers calculated that the increased amount of long-wave radiation is in part due to the high concentration of gases such as CO2 - which is considered to be the cause of 'man-made greenhouse effects'. But, the increased amount of steam seems to have a greater effect, accounting for about 70% of the temperature increase that the study noted.

Not all regions in Europe are equally affected. Eastern European countries became warmer with an increase of 2 degrees Celsius per decade - significantly more than in Western Europe. According to new research, it may be due to differences in humidity. Humidity has increased rapidly in the East but not in the West, where drought in the Iberian Peninsula probably limits water evaporation.