Prize recipient 2023 | Jens-Christian Svenning

What is your research about?

I research biodiversity and ecosystems. Basic research driven by curiosity is at the heart of my work, but I’m also very keen to help secure a bright future for humankind and all other life on Earth.

There are many fundamental things we don’t yet understand about the Earth’s amazing diversity of plants, animals and other organisms, such as how many species can live together in a given area, and the mechanisms that permit and restrict this co-existence. The same applies to the ecosystems that these species build in interaction with the climate, soil and so on. For example, there are still many unanswered questions about the structure and function of natural ecosystems in the time before modern human intervention.

I’m carrying out research into how biodiversity and ecosystems worldwide are being affected by climate change and humankind here and now. I’m interested in what effects this can be expected to have in the future, and how we can best conserve and restore nature. My research is characterised by taking a global view and delving deep into the past to cast light on both the present and the future.

What are the challenges and prospects for your research?

There are masses of challenges! Although the quantity and availability of data are improving rapidly, thanks to everything from satellite imagery to digitisation, there is often a shortage of precise data on, say, particular species or ecological mechanisms. For this reason, my team is constantly carrying out field-based surveys both in Denmark and around the world – including Central Europe, Africa, South America and the US. 

It can be a challenge to gather enough data and for them to cover a sufficiently large area and timeframes of perhaps decades or centuries. But finding solutions to these challenges is also an inspiring part of my work – maybe using new methods or sources of data or establishing international collaborations to bring about field campaigns around the world.

At the same time, there are obviously great prospects. The global community faces existential global crises in the form of accelerating global warming and an escalating loss of biodiversity. My research contributes directly to better understanding these crises and the ecological opportunities we have to address them.

How did you become interested in your research field?

My interest in biodiversity and ecosystems dates back to early childhood. I’ve always been keenly interested in nature – whether just outside the door, around the world or in the past. As a teenager, I realised that I wanted to study biology at university so that I could work in the area professionally. In the second year of my studies, I contacted my eventual PhD supervisor Professor Henrik Balslev with a view to carrying out a project in the tropics, the most species-rich part of the world, and we discovered a common interest in palm trees, rainforests and ecology. 

This led first to a dissertation in 1992-1993 and later my doctoral thesis in 1994-1999 on the ecology of palms in Ecuador. The focus was not only on testing basic hypotheses about how tropical plant communities form, but also on how they are affected by human activity. This was followed by a postdoc at the Smithsonian Tropical Research Institute in Panama studying the structure of tropical forest plant communities, which included lots of experiments in the field. 

Alongside my PhD work and my first postdoctoral position, I developed an interest in biogeography (the geography of biodiversity), macroecology (ecology at a continental and global scale), historical ecosystems (especially the last few million years) and nature conservation. I’ve been able to build on and integrate all of these elements in my subsequent work.

What are the greatest insights or discoveries you have made?

The lion’s share of my research is carried out together with colleagues and students and is therefore a joint effort. The greatest discoveries and insights resulting from my research concern the importance of prehistoric climate change for biodiversity and ecosystems today, the ecological importance of megafauna, and humans’ own living conditions.

There have been dramatic changes in the global climate over recent millions of years, with frequent ice ages. My research has demonstrated highly selective extinction of trees in the temperate zones of the northern hemisphere, with more thermophilic – or heat-loving – genera retreating and dying out in places like Europe. During the ice ages, most species were driven out of northern areas, including Denmark. 

My research shows that many species have recolonised only very slowly since the last ice age, and that many species of tree in Europe have still only partially spread to areas with a suitable climate despite having had more than 10,000 years to do so. I’ve also shown that the combination of extinction and slow expansion of many species means that areas with a relatively stable prehistoric climate are home to far more of Earth’s many naturally rare species than more unstable areas.

My research has also looked at the importance of megafauna – large animals – both today and in the recent past. I’ve shown, for example, that the massive loss of megafauna around the world over the past 50,000 years has markedly changed the strength of key processes in the world’s ecosystems, greatly reducing the depletion of plant biomass and plants’ distribution in the landscape. I’ve also shown that, before this loss of megafauna, ecosystems in Western Europe in climate conditions similar to those today had a surprisingly varied vegetative structure and were often densely populated with large herbivores which were able to generate this variation.

In addition, I have an interest in the importance of the environment for human lives. For example, in a study of almost a million Danes, I showed that growing up in green surroundings is associated with a reduced risk of mental disorders later in life. Most recently, I’ve contributed to research showing that around 2 billion people in 2090 are at risk of living in extreme heat similar to the hottest parts of the Arabian peninsula and the Sahara today.

What does it mean to you to win the Carlsberg Foundation Research Prize?

It is a particularly great honour for my research to be recognised in this way with the Carlsberg Foundation Research Prize. My research is largely carried out in collaboration with other researchers and students on my team at Aarhus University, both nationally and internationally, so I am very grateful to all those who have contributed.

Tell us about your background, family and leisure interests

I grew up in Jutland in Denmark, mainly in Holstebro. My family has a great interest in nature and social issues, with a strong international and historical perspective, and I have absorbed this interest since early childhood. One important inspiration was the work of my father, Lauritz B. Holm-Nielsen, as a tropical botanist in South America. Another was my mother, Ane-Marie Svenning, a teacher with a keen interest in nature and social issues who supported my academic pursuits. My grandfather’s background as a sea captain on routes far away from Denmark, such as in the Pacific, should also get a mention.

I have a broad interest in nature and culture, which I bring into my work and also as much as possible into my spare time with my family. I’m married to Else Magård, a biologist and centre manager at Aarhus University. We have three children: Rolf Svenning, who is studying for a doctorate in computer science, Asger Svenning, who is studying for a doctorate in biology, and Liv Magård, who is studying social sciences and mathematics at upper secondary school.