According to the astronomical calendar, summer officially started on June 21, but days before that date a heat wave had already hit the Czech Republic. Was that recent tropical period a random occurrence or is global warming to blame? In this week's Talking Point, Pavla Horakova talks to climate experts about the trends and changes the Czech Republic and the rest of Europe can expect in the near future.
The year 2001 was the 23rd year in a row when the average temperature of the air above the surface of the earth was increasing. In the Northern Hemisphere, 2001 was the warmest year since 1861. How about the Czech Republic? Jaroslava Kalvova from the Department of Meteorology and Environment Protection at Charles University in Prague studies the climate in the Czech Republic.
"During the 20th century, the temperature was rising. It was rising in two distinctive stages - between the years 1910 and 1945 and then again from 1976 until today. In between those two periods there were the 1970s with genuine winters and plenty of snow. It is unfortunate for winter-sports lovers that winter temperatures are rising again and there are fewer and fewer days with below zero temperatures."
The Czech Republic is a landlocked country in the heart of Europe but none of the oceans are so far away that they do not have a significant bearing on the climate of the country - a basin surrounded by mountain ranges not too high to stop rain clouds. What in fact influences the climate in the Czech Republic? Vaclav Cilek from the Institute of Geology at Charles University is an expert on global climate.
"We in the Czech Republic are under the influence of the North Atlantic oscillation. It is something like El Nino. It is a system mostly of the westerly weather that is coming with humidity and temperature. It is something like the low over Iceland and the high over the Azores Islands. If there is a big difference of the pressure then the winds can blow into the interior of the Czech Republic and usually bring an oceanic kind of climate. But in wintertime another situation may take place. For example when the high Siberian circulation occurs, under such conditions we are under the strong influence of harsh and dry winters."
So the climate in the Czech Republic is influenced by two different climate systems. For almost a century the weather has been getting warmer. Can we expect more of the same in the future? Vaclav Cilek again.
"We as the Czech Republic are just in the middle, in between these two large systems. We do not have any clear trends for the Czech Republic. Some warming is probable but we can imagine that this Mediterranean climate is going to fight with the Scandinavian climate over a certain period, over one month or so. A heat- wave from the Mediterranean may be quite common but then some cold weather with high precipitation may come from Scandinavia. The future scenario for the Czech Republic should be a kind of mixed scenario which expects more extremes to come."
The rest of Europe is experiencing climate changes, too. Vaclav Cilek told me about some changes recorded in Europe and their possible implications.
"The climate in Europe is changing. There are likely to be major changes especially in Southern Europe, in the Mediterranean realm. It's already happening: droughts, more dry seasons accompanied by higher temperatures, take place. So what does it mean? The harvesting of crops is likely to be more difficult. The frequency of heat waves is getting higher. It may mean that for example for the future of tourism that fewer people would be willing to go to the Mediterranean for their summer vacation. On the contrary, Northern Europe and Scandinavia is getting a little bit warmer but the precipitation is higher. In some regions it is about 40 percent, in other regions something like 10 percent on average."
Global warming is generally ascribed to the greenhouse effect. To put it simply we can say that certain man-made gases, referred to as greenhouse gases, allow incoming solar radiation to reach the surface of the Earth but prevent the infrared radiation from flowing back. They work much in the same way as panes of glass in a greenhouse. As far as the production of greenhouse gases is concerned, Jaroslava Kalvova is worried.
"If people continue to behave in this way, releasing more and more greenhouse gases, I'm afraid the pessimistic scenario will come true. The influence of human activities will have more and more impact on the climate and in 50 years temperatures in the Czech Republic will increase by 3 degrees Celsius. This does not take into account natural climate changes. The climate might get warmer naturally and we'll only be adding to it with our activities."
All industrial countries, including the Czech Republic, contribute to global climate changes by releasing greenhouse gases into the atmosphere. But does the Czech Republic and its industry also directly influence its own local climate? Jaroslava Kalvova from the Department of Meteorology and Environment Protection.
"The influence of humankind - I'm talking here about releasing greenhouse gases into the atmosphere - is global. The Czech Republic is then affected by changes in atmospheric circulation, air currents etc. But that does not mean that people in the Czech Republic do not contribute to local climate changes themselves. People can change the climate on a smaller scale. For example, we know that Prague is warmer than the rest of the country. There is no doubt that people have always influenced their surroundings, including their local climate."
Earlier we heard that the climate in the Czech Republic is influenced by two atmospheric systems originating far away from this country. Do we know whether the Czech Republic has a direct influence on other parts of the earth? Vaclav Cilek from the Institute of Geology.
"The atmosphere is somehow a unified phenomenon, it is a global phenomenon and large masses of air can move within a few days over the whole continent. One of the really interesting results of the last maybe a year was a study of the sulphate aerosols. Sulphate aerosols usually form the nuclei of the precipitation. Simply, the cloud will result from the enhanced production of carbon dioxides. But some of the recent research has proved that the aerosols have in fact a cooling effect on the atmosphere. And if you take a model which counts with the cooling effect and if you take the direction of the winds in the Northern Hemisphere, you will find a close relation between the strength of the winds over Sahel, over North Africa, and the amount of sulphur oxides over Central Europe. And it's believed that at the beginning of the 1990s the de-sulphurisation of the power plants in the Krusne hory Mountains and elsewhere has helped rains to come to the Sahel region. So maybe the changes in Krusne hory have contributed to better living condition in North Africa."
Global climate has changed many times during the history of humankind, usually bringing negative implications for whole civilisations. The current development suggests we are going through such a change and futurologists present us with various science fiction scenarios. Is there a reason for panic, I asked Vaclav Cilek?
"There is always a reason for panic, but it's probably not the best attitude. I think that we are facing decades of major changes. Many historical analyses have shown that the most profound changes of the humankind happen on the intersection of natural changes, that means climate changes and social changes and we are just now in position when we are facing both."