One of the youngest climatologists in the Czech Republic and Slovakia, Jozef Pecho, explains how the Earth is warming globally, why the glaciers in the Arctic are melting and how each of us can mitigate the negative effects of climate change.

How would you briefly and clearly explain to the lay public what climate change means? These are changes in all known physical (meteorological) variables, which describe not only the current state of the weather, but also its average character over the long term, i.e. the climate. These are primarily changes (increase) in air temperature, atmospheric precipitation, air humidity, cloudiness and, last but not least, air flow. Climate change is therefore far from being just about global warming, even though it is understandably at the beginning of it, because all other quantities change mainly depending on changes in air temperature. How does this affect the population? The rapid retreat of mountain glaciers, the shrinking of the sea ice area in the Arctic, the rise of ocean levels, or even the shift in the distribution of plant and animal species, are only the most noticeable manifestations of climate change, and many of them are beginning to bring rather unpleasant consequences for human society. For example, the less frequent occurrence of rainy days in some areas of the world leads to long-term drought, which poses a problem not only from the point of view of food production, but also the ability to supply people with water. Climate change also leads to changes in the nature of the weather, which in many areas becomes more extreme (heat waves, extreme precipitation, sudden changes in air temperature).

We hear from everywhere that we are responsible for global warming. Is it true? To a large extent, this is true, because behind the mentioned changes in the chemistry of the atmosphere, human economic activities, such as energy production and consumption, transport, deforestation, intensifying agriculture, but also the production of cement, for example, must be seen. Each ton of burned coal or oil leads to the production of carbon dioxide, which, along with water vapor, is one of the most important greenhouse gases. They can retain in the atmosphere the heat generated by heating the earth's surface by direct sunlight. This heat spreading from the earth's surface to the atmosphere is retained by the molecules of greenhouse gases and "reflected" back downward, to the earth's surface. The problem, however, is that this effect is constantly and rapidly increasing precisely as a result of higher concentrations of carbon dioxide and some other greenhouse gases, which is mainly manifested by an increase in the average global temperature.

We see the most examples of the negative effects of climate change on people's lives on the African continent, especially in developing countries. Why? Developing countries are often too poor to cope quickly with its consequences. However, it is far from just about money, but also about the right "know-how". In Europe (compared to the developing world), we still have better material conditions to fight these impacts. However, if the rate of climate change exceeds the limit of "tolerability" in the coming decades, the developed world will also have big problems, including the most economically powerful states.

In Slovakia, don't we have to worry that climate change will change our lifestyles? Manifestations of climate change are also visible in Slovakia. Increasing the average annual temperature has a positive effect on the extension of the main growing season. However, it must be admitted that the more negative manifestations of climate change are appearing more and more - extreme weather in the form of stronger storms, more frequent floods, longer lasting droughts and more extreme heat waves in the summer. Climate change will definitely require a change in our lifestyles in Slovakia as well. However, the move away from a consumer society, the transition to local self-sufficient agriculture, the use of local energy sources can be quite positive changes for our society.

Global warming is not to be taken lightly. However, there are also opinions that nothing serious is happening - the Earth can handle everything. So how is it? Probably for the first time in the history of the Earth, there is a biological creature on its surface that can influence the climate on a global level. However, if this action is uncontrollable, then it is a very dangerous game - not only for us humans, but also for the entire biosphere. Earth can certainly cope with this rapid climate change. But the question is whether we, humans, can do it too, with our complex technological civilization.

How ​​are we doing with livelihood security? Are there really less fish in the seas and fewer crops (grains or vegetables) due to extreme droughts and lack of rain? Food security in developed, and especially in developing countries, is at great risk due to the effects of climate change. The key problem of the future is how to feed the ever-increasing number of the world's population at a time when food production is beginning to hit its limits and is also threatened by climate change. The lack of food manifests itself in an almost uncontrollable increase in the prices of basic foods. The overall state of world stocks of selected food commodities is also falling due to such events as the large losses of the grain harvest in Russia in 2010 (as a result of the extraordinary heat in the summer of 2010). The current oceans are in a truly desolate state. Not only commercial fishing, but also rapid changes in the ocean environment (increasing temperature and water acidity threaten entire food chains, especially in tropical regions) significantly threaten the productive function of this environment, not to mention the consequences of ocean pollution with pesticides, heavy metals, oil substances or even plastics.

You are one of the youngest climatologists in Slovakia. You are completing your doctorate at the Academy of Sciences in the Czech Republic. Why did you choose climatology? Climatology interested me only in high school and then mainly in college. I have been working in this field for about 15 years. It is one of the most complex natural sciences we know. You must have the basics not only in meteorology itself, but also in geography, statistics, physics, geology, history, chemistry and biology. It takes years to understand at least the most basic laws of climate formation and its long-term changes. A person in this field is always learning, always discovering new things. And that is the most beautiful thing about climatology.

At the November climate conference of SKCH in Bratislava, you and your colleague Alexander Ač gave an interesting paper. What exactly did he do? We presented the issue of the connection between the occurrence of various types of weather extremes and climate change - the results of research into heat waves, drought, extreme precipitation, hurricanes and typhoons and other phenomena from around the world. The article demonstrates that certain types do indeed tend to be more prominent or occur more frequently in warmer climates. It turns out that some extreme weather events might not have happened without climate change, or might have happened on a much smaller scale.

Professor Milan Lapin is not only a top Slovak climatologist, but also a respected and recognized expert abroad. Thanks to him, concepts such as climate change or the greenhouse effect of the atmosphere reached the "ears" of the lay public. I was very lucky that I could not only study with the professor, but also work with him. However, I think that despite such a prominent personality as Professor Lapin, the problem of climate change is paid little attention in our country. However, it is positive that municipalities are starting to deal with it. They are aware that local development will be very limited in the future due to the effects of climate change.

How seriously should catastrophic scenarios and weather forecasts for the next century be taken? The scenarios of the future development of the climate in the next century do not bring a very pleasant perspective. The global air temperature is likely to rise by 3 to 4°C by the end of this century. It may not seem like much, but when it happens, it will be the fastest climate change in Earth's known geological history (at least 60 million years). Everything will, of course, depend on the direction in which society as a whole will develop, how we will solve our problem of getting enough energy, how we will deal with population growth and a whole host of other global problems. However, it will be crucial to limit our huge emissions of carbon dioxide to the lowest possible level.

How can we stop the process of global warming and the negative effects of climate change? I am afraid that we are no longer able to stop global warming and the negative effects of climate change at this stage. Whatever we do now, warming will continue for several decades, mainly due to the thermal inertia of the oceans and the fact that global temperature is only beginning to catch up with the current high concentration of CO2 in the atmosphere. What we can certainly do, however, is try to moderate the rate of this warming to a more tolerable rate (mainly by reducing CO2 emissions) and thus limit the most negative impacts. The issue of climate change is very crucial for all of us. Probably never before in history has it been so extremely important for us to deeply understand the changes taking place around us (and to reevaluate our lifestyle and approach to nature). It is about our collective survival.

Text: Bozena Baluchová, Photo: archive of Jozef Pecha The interview was prepared for the magazine Charita 4/2012, respectively. 1/ 2013 (topic: Climate education).