What were the decisive factors in your choice to study the geographical sciences?
I think it might be a bit of a disappointment to you and the readers. I finished school in the 1990s and those were not yet times when young people could plan their futures far in advance. I come from a small town and after finishing school, you had to go away to study, so as not to end up in the army. I had always been interested in geography, it was a pleasant subject at school, travelling was an interest and that was my main motivation. I never planned to become an academic in the field. I wanted to study something that would pique my interest. Even during my studies the choice of specialisation was decided by accident. At the moment I had to choose a specialisation, I wanted to go for geomorphology but it turned out to be impossible, as no MA studies existed in the subject, so I had to take something as a replacement. I chose limnology, i.e. the study of lakes, and for the next three years that is what I studied. Afterwards doing a doctorate in limnology turned out to be not really possible, but an option for geomorphology did exist, so I switched to geomorphology. I think, however, that it was the best thing that could have happened to me. As part of my MA I did different things to now, but connected all the same since I’m still working on the subject of lakes in the Department of Geomorphology and Quarternary Geology, albeit studying lake sediment while as I was doing my limnology specialisation it was the processes which occur in lake water.
You are active in the ClimPol Project, please tell us something about it.
The main area of activity for me and the people I work with is climate change. I must stress, however, that I am not a climatologist. Climate change is also of interest to people who study lake sediment, but only in the distant past. Inevitably, we do not work on metrological data in the sense, for example, of measuring temperature, we only try to reconstruct what the temperature was like 500 or 1000 years ago, on the basis of indicators preserved in lake sediment. Still, cooperation with climatologists is essential and our research projects complement each other. The ClimPol Project is already a few years old and I’ve managed to work alongside Professor Martin Grosjean from Switzerland, who basically suggested we work together. We wrote a project as part of the Polish-Swiss Research Programme which was given the go-ahead. Since 2011 we’ve been working in a team of over 20 people from five academic centres in Poland and from the University of Bern. At the moment, the project is nearing completion – we’ve done all the laboratory and analytical work, so the last few remaining months will mainly be dedicated to writing the publication. In the end we will have a reconstruction of the changes in air temperature in north-eastern Poland over the last 1000 years. I must say it was fascinating work, particularly because it was a large team of diverse people. We had geographers, geologists, climatologists, physicists and even historians. Joining the information from such different branches of knowledge is a fascinating, if difficult, task. You have to realise that not everything can be precisely pieced together in these reconstructions and there is always an element of uncertainty. There are some things which are to a great extent unverifiable, and it is impossible to check what we end up with in another way which would give us an unambiguous answer. Recently I succeeded in getting a new project from the National Science Centre called ClimPol-2K which is about extending the reconstruction in such a way that it covers 2000 years. In recent times, the figure of 2000 years has become something of a standard for the analysis of long-term climate change and for providing a model of what will happen in the future. The new project will last three years. We hope that our reconstruction for northern Poland will be something unique and appreciated abroad since there are no comparable studies for our region.
What can lake sediment tell us about climate?
Sediment forms at the bottom of every lake from the dead remains of aquatic organisms and from what flows into the lake from its rivers. All of these things from the water column slowly fall to the bottom, forming a layer of sediment. If we can take this sediment intact from the lake bed, which we do with special probes inserted into the bottom to remove a column of sediment called a core, we then have a complete record of how the sediment was formed over time. This sediment contains the remains of various organisms which were living in the lake when it formed. There is an enormous variety of such organisms but only some are significant as indicators. We might find plant pollen and we can reconstruct the range of plants that surrounded the lake based on their frequency. We have organisms which are incredibly sensitive to temperature and which can only live in a strictly limited temperature range, so if the species composition of these organisms in the sediment changes, then we know that the temperature changed too. We also have to know the precise age of the sediment to confirm when these changes took place. There are different ways to determine age, but we work from the sediment laid down annually, where layers of various growth are preserved. It’s very similar to tree rings. If the core contains preserved layers, i.e. annual growth, then by counting them we can determine the age very precisely in every part of our core. In the ClimPol Project we took a core about four metres long and counted all the annual growth and it turned out that we had just over a thousand. By studying samples from all of this growth, we can establish what conditions were like for that specific year.
What can be said about our climate 1000 years ago?
Of course the analysis of samples gives us a concrete figure, so we can reconstruct a temperature, say 15° Celsius. You have to remember though, that these calculations are prone to slight uncertainty and we can’t take these results literally. We prefer to analyse the variance in values obtained, so by mapping out temperature changes over several hundred years we can see certain periods where it was definitely warmer and certain periods where it was definitely cooler. Although we use concrete values, I wouldn’t recommend interpreting them literally, for example by picking a specific year and checking what the temperature was. That would be deceptive. We were, however, very clearly working on changes in temperatures and significant ones at that, which can be observed by following long-run variance. We have managed to establish that, over the past millennium, the last 100-150 years have been a period of systematic rise in temperature, and that the last few decades have been the warmest period in a thousand years. This period of global warming was preceded by a long quite cool period, known as the little ice age. Temperatures were at the time conspicuously lower for several hundred years, the winters being particularly frostier. At the start of the millennium, however, about the year 1100/1200, we were dealing with what is called the medieval climatic optimum – a relatively warmer period, although obviously not as warm as today. We should bear in mind that many historical events, the migration of peoples, wars, conflicts and epidemics had a basis in climate changes. At the time, climate dictated what happened in society to a much greater degree than at present, since now we can cope better with adverse climatic conditions. Climate change reconstruction like ours had been done many times, the most reliable being those carried out with ice cores, since they give a global picture of change. So we know, more or less, how temperature has changed on Earth over the last millennium. We also know that these changes were geographically diverse, so local analyses are very important. If we consider the last two thousand years as a whole, we can see a long-term process of cooling related to the end of the Holocene. After a long period of glaciation, about 11,500 years ago, warming occurred, and the Holocene, or the Interglacial, period began. From the longer perspective of time, which we get from the ice cores and from ocean sediment cores, we know that the interglacial normally lasted for between ten and twenty thousand years. So we are now at the end of our own interglacial. The problem is that this cooling trend has been quite brutally interrupted in the last 100-150 years, where the tendency has noticeably reversed, most probably due to human activity. This is all very important in the context of future change. In order to evaluate the future, we have to know the past and by limiting this past to several dozen or 150, 200 or 250 years for which we have measurements, we can in quite a significant way have an impact on our false perception of the changes we are currently experiencing. The longer the time span we have, the better the context in which we are able to locate the situation today and what will happen in the future.
What would you say to someone who wanted to study geography?
People who enrol for geography studies have a false idea leaving school and are confronted with a completely different reality. It’s not pleasant for everyone. Geography at university level is slightly different and has nothing to do with looking at maps. You have to be aware that it is divided into a lot of particular branches. Generally, we have human geography, concerned with human activity and all related processes, and physical geography, which is concerned with the natural environment. The student has to decide which of these to do. I think it’s a fascinating course of studies. One of the unique qualities about it is that, apart from normal lessons (lectures, classes), we have laboratory classes and field work. This is one of the elements of my studies which I recall most fondly and this probably hasn’t changed for students down the years. The situation where a whole group of students goes off to a given place and has to take measurements and make observations makes it an interesting and diverse course of studies. It is not monotonous work and it could be five years of very interesting studies.
Do you have time for a hobby?
I find myself watching friends doing something that you might call a hobby, orienteering, for example, and I just don’t have time. Work really does take up a lot of my time but it also gives me a great deal of pleasure. Sometimes I catch myself doing work at home in my own free time because it gives me such pleasure. But of course I don’t just live for work alone. As a student I travelled a lot with my future wife and friends and that is something that has remained with me. We made a few trips to the Himalayas, amongst others. My dream is to go back there and this dream is taking on genuine form. Last year we were supposed to go, but unfortunately it turned out that organising a journey which lasts a month isn’t so easy for people who each have their own obligations. It didn’t work that year, so we postponed it to this year and I hope that we’ll manage. Travelling has always been a passion of mine, my work of course gives me great opportunities on the travel front. This year, for example, as part of my cooperation with colleagues in Switzerland, we’re off to Ecuador. We are going to carry out research on the lakes in El Cajas National Park, which will be an extraordinary venture by itself, not counting the research aspect. A more sedentary occupation is listening to music. I played the guitar at school and at the start of my studies. I still intend to refresh my skills and one day play in some blues band.
Interview: Krzysztof Klinkosz
Photos: Piotr Pędziszewski
