NESSC - Netherlands Earth System Science Centre

A Collaborative Scientific Environment The Netherlands Earth System Science Centre (NESSC) brings together scientists from a variety of disciplines. We spoke to Professor Jack Middelburg, Professor Stefan Schouten and Dr Anna von der Heydt about the research they are conducting within NESSC, and its importance to our understanding of the climate system.

Marine Biogeochemistry

Geochemistry Jack Middelburg is a Professor of Geochemistry at the University of Utrecht.

EU Researcher: What are your main

EUR: What materials are you looking at

research interests?

Professor Middelburg: My research is at the interface of biology, geochemistry and palaeoclimate science. A lot of climate research is about the short-term, in NESSC we deliberately focus on the longer-term response.

EUR: Does this involve looking at the historical record?

Professor Middelburg: Yes. So in NESSC we aim to integrate the geological record, the historical and instrumental records. NESSC researchers have been using a type of organism called foraminifera, which produce very tiny shells.

Foraminifera are essentially one of the best recorders of past ocean chemistry which we have as scientists. Inferring past climate conditions implies understanding the biological processes that govern shell chemistry of these organisms.

EUR: Will this research help provide an insight into the likely nature of climate change in future? Whether it will be incremental or more dramatic?

Professor Middelburg: We look at the non-linear responses of the climate system, the tipping points. We investigate how warm it will be in the future, and whether the road towards warming will be bumpy or smooth.

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Stefan Schouten is a Research Scientist at the Royal Netherlands Institute for Sea Research (NIOZ).

Climate sensitivity Anna von der Heydt is an Associate Professor at the University of Utrecht, with interests in marine and atmospheric research, and physical oceanography.

in your research?

EUR: What are your main lines of research?

Professor Schouten: We’re essentially

Dr von der Heydt: One is the evolution of climate sensitivity, which tells us how much warming (global mean temperature) we expect after doubling the CO2 concentration in the atmosphere. There are many feedbacks involved in the climate sensitivity, which can change their strength over time. I am interested in how different these feedbacks were at certain times in the past, when the climate was warmer.

looking at fossil molecules, marine material that’s been buried for hundreds of thousands - even millions - of years. We’re trying to detect and retrieve natural compounds made by a host of different microbes from the ocean floor. We analyse them in the lab and investigate the circumstances under which these microbes lived.

We’re focused on the Phanerozoic period, which is the window within which our techniques are effective. The last 500 million years or so is quite a good period for us to apply our proxy techniques to reconstruct the past climate.

EUR: Is one of these techniques the stable carbon isotopic fractionation associated with photosynthesis?

Professor Schouten: Yes. This tool has been commonly used over the past 30 years or so, but we’ve looked at a specific molecule called phytane – part of chlorophyll – which was far more ubiquitous and had a far longer history than those previously used.

EUR: Is the CO2 concentration related to

EUR: Is one of the periods you’re looking at the mid-Pliocene? Can you draw certain parallels with the climate then and the climate today?

Dr von der Heydt: In the Pliocene the CO2 concentration was more or less like it is now, yet it was considerably warmer than today. We have performed quite a few model simulations of the climate in the Pliocene epoch, and we can explain lots of warming and regional changes. However, it turns out that for many specific things, what we see in the Pliocene is not only due to the CO2 concentration and the fact that the climate is equilibrated, but also to different land-sea distributions and vegetation and boundary conditions.

the stable isotopic carbon fractionation?

EUR: Have you also looked at other periods?

Professor Schouten: There are two stable isotopes of carbon – 12C and 13C. It’s welldocumented that if phytoplankton fixates CO2, they not only accumulate 12C, but also the heavier one, 13C, simply because it’s there.

But they slightly dislike it. If the CO2 concentration drops, they are effectively forced to fixate more 13C, even though they don’t like it.

Dr von der Heydt: We’ve also been looking at the Eocene-Oligocene transition within NESSC, which occurred around 35 million years ago. Before that time, it was very warm on earth. At some point the Antarctic continent became glaciated, which was a huge transition.

We have simulated a lot of different versions of the climate before that transition, and studied them on the Antarctic continent.

Lakes, rivers and ponds in the East Siberian Arctic form an ideal landscape for the production of methane gas. Photos: Joshua Dean

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How much warmer will the Earth become in our future?

The Earth is getting warmer, but how much warmer will our planet be in the future given a certain level of CO2 emissions? We spoke to Professor Jack Middelburg about the work of the Netherlands Earth System Science Centre (NESSC), an inter-disciplinary research programme which aims to shed new light on the global climate system.

The likely future evolution of our climate is the subject of a great deal of research, with scientists seeking to build a deeper understanding of the global climate system which can then inform the development of more detailed projections.

The Netherlands Earth System Science Centre (NESSC), a programme bringing together experts from several Dutch institutions to conduct research into climate change, is making an important contribution in this respect. The centre brings together researchers from a wide range of disciplines to address these questions, including maths, earth sciences and microbiology. Research in NESSC is organised around five main themes, the first three of which are related to how much carbon we will have in the atmosphere in future. NESSC aims to learn how hot our planet will be in future, and how fast the rate of temperature increase will be. Will there be warnings of future change? Are there certain tipping points which will shift the climate system into a different phase?

Climate system Research in NESSC is primarily focused on investigating how the climate is likely to change over longer timescales, looking ahead to improve models of the climate in 2050, 2100, or even further into the future. While there is a general consensus that the Earth is getting warmer, uncertainty remains over the relationship between the level of CO2 emissions and the likely extent of temperature change in future. “How warm will the world be in future, given a certain amount of CO2 emissions? If CO2 emissions double, will it lead to a warming by 1.5 degrees?” asks Jack Middelburg, Professor of Geochemistry at the University of Utrecht and the Scientific Director of NESSC. This is a challenging question, as processes occurring on multiple different timescales are involved. “There are

Hunting for methane producing bacteria: measurements in the field. Photo: Michiel in ‘t Zandt

transformed into anions – negatively charged ions – and cannot escape any more. The number of CO2 molecules that are transformed into anions depends on the buffering capacity,” he explains. In his research, Middelburg has been investigating how the buffering system of the oceans works. “At what timescale does it occur? How does it affect the production of calcium carbonate? Can we show that calcium carbonate is dissolving because of the CO2 entering the ocean? How much calcium carbonate dissolution can we see? These are the types of questions I have been addressing in NESSC,” he says.

Tipping points

processes like cloud formation, which occur on really short timescales. There are also processes on intermediate timescales, like the inclusion of more CO2 in the atmosphere,” explains Middelburg. “There are also very long-term feedbacks, such as changes in the weathering of rocks and changes in the carbonate system of the oceans.”

palaeoclimate research community, and Middelburg says their work is an important part of NESSCs overall agenda. “We try to combine the modern, instrumental records with the historical records, the geological records. Essentially we use the response of the Earth system to carbon perturbations in the past to get an integrated view of what

Essentially we use the response of the Earth system to carbon perturbations in the past to get an integrated view of what we can expect in the future.

The research undertaken within NESSC relates to many different timescales, as assessing the long-term effects of increase on global anthropogenic CO2 warming and sea level is a complex task.

This underlines the importance of bringing together researchers from different disciplines, who can bring their own expertise to bear on the topic and help build a more detailed picture of the climate system. “We have established a community of Dutch scientists in NESSC, who are working on all the aspects of climate change,” says Middelburg.

For example the Netherlands has a very strong

we can expect in future,” he explains. “We can learn from the past record that a carbon perturbation not only causes temperature rises, but also other changes, such as ocean acidification and rising sea levels.”

Around 45 percent of the CO2 which we emit as humans stays in the atmosphere, while the rest is equally divided between terrestrial and ocean uptake, leading to the acidification of the oceans. A lot of Middelburg’s research within NESSC over the last couple of years has centred on the buffering system of the oceans, a kind of resilience mechanism that limits the extent of change caused by CO2 uptake. “CO2 is a reactive gas, it reacts with water. If 20 CO2 molecules enter the ocean, the majority are

A further major topic of investigation in NESSC is the concept of tipping points, a threshold beyond which there is a general, often abrupt shift in the climate system. Changes to the North Atlantic circulation and the impact of permafrost thawing are two issues of concern with respect to tipping points in the global climate system. “There are quite a few people working on permafrost thawing and methane release in NESSC. There are feedbacks that are happening on a monthly, seasonal timescale, as well as feedbacks which are happening on longer timescales,” says Middelburg. The wider aim in this research is to quantify climate sensitivity, to essentially understand how much warming can be expected for a certain amount of CO2 emissions. “We have to distinguish between climate sensitivity - which is on the shorter term - and the longer term, which we call earth system sensitivity. This is when you really take the long-term feedbacks into account,”

NESSC Netherlands Earth System Science Centre

Project Objectives

Growing tropical red mangrove trees in the nursery in Wageningen. Photo: WUR / NESSC

continues Middelburg. “At what timescale should we take into account which feedbacks?

Which feedbacks are important?”

This research can then inform the development of long-term climate models.

This focus on the longer-term timescales is well-aligned with the research interests of several groups in the Netherlands, not only in palaeoclimateology, but also anaerobic microbiology, ice dynamics and non-linear processes. “There are people in NESSC looking at questions about the climate from a variety of different perspectives,” stresses Middelburg.

NESSC itself is nearing the end of its funding term, but with climate change an ever more pressing concern, Middelburg says this research will continue into the future, with scientists exploring various different possibilities. “Some of us are working on a more youth-inspired initiative, while there is another funding stream in the Netherlands focused more on climate solutions, so CO2 removal technologies,” he outlines. “Some people are thinking about the financial consequences of climate change, while others are exploring links to the social and economic sciences.”

At NESSC a diverse group of renowned scientists with backgrounds in physics, earth sciences, ecology and mathematics investigate diverse aspects of the climate system, such as the Earth’s climate sensitivity to CO2, methane emissions, and climate tipping points. By combining the knowledge of different disciplines we aim to improve our understanding of climate change and to enhance future climate projections.

Project Funding

NESSC is funded by a Gravitation grant from the Dutch Ministry of Education, Culture and Science, which supports excellent research. The programme has received further funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie, grant agreement No 847504.

Project Partners

NESSC is a virtual research centre comprising experts from the NIOZ Royal Netherlands Institute for Sea Research, Radboud University Nijmegen, Utrecht University, VU University Amsterdam and Wageningen University.

Contact Details

NESSC Office Utrecht University, Faculty of Geosciences Vening Meineszgebouw A Princetonlaan 8a 3584 CB UTRECHT The Netherlands T: +31 30 254 5169 E: info@nessc.nl W: https://www.nessc.nl Prof. dr. Jack Middelburg Dr. Anna von der Heydt Prof. dr. ir. Stefan Schouten

Tipping Point Ahead Education How will the oceans of our earth look like in the (far) future? Will climate change worsen forest fires or sea level change?

These and many other topics related to our changing climate are addressed in the diverse set of teaching materials of Tipping Point Ahead – the educational outreach program of NESSC that aims to inspire and engage students in secondary education.

Tipping Point Ahead offers a range of different educational materials. In crisp, informative clips young climate researchers enthusiastically tell about their research and what inspired them to become a scientist. The website also hosts

a growing selection of teaching materials, from extensive teaching modules to a still growing number of ClimateSnacks: brief assignments that introduce a facet of climate change in an original way!

Visit our website to learn more about our movie clips or teaching materials!

Prof. dr. Jack Middelburg is Professor in Geochemistry at the Faculty of Earth Sciences, Utrecht University, and Scientific Director of NESSC. Dr. Anna von der Heydt is an Associate Professor at the Institute for Marine and Atmospheric Research (IMAU), Utrecht University.

Prof. dr. ir. Stefan Schouten is Research Scientist at the Royal Netherlands Institute for Sea Research (NIOZ) and professor of organic geochemistry at Utrecht University.

E: redactie@tippingpointahead.nl W: www.tippingpointahead.nl

Weathered rocks in the Namib desert.

Photo: Robin van der Ploeg.

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