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Thawing permafrost produces more methane than expected

19. März 2018 - 11:42

Methane (CH4) is a potent greenhouse gas, which is roughly 30 times more harmful to the climate than carbon dioxide (CO2). Both gases are produced in thawing permafrost as dead animal and plant remains are decomposed. However, methane is only formed if no oxygen is available. Until now, it was assumed that larger amounts of greenhouse gases are formed when the ground was dry and well aerated – when oxygen was available. Christian Knoblauch and his colleagues have now demonstrated that water-saturated permafrost soils without oxygen can be twice as harmful to the climate as dry soils – which means the role of methane has been greatly underestimated.

Knoblauch has, for the first time, measured and quantified in the laboratory the long-term production of methane in thawing permafrost. The team had to wait for three years before the approximately forty-thousand-year-old samples from the Siberian Arctic finally produced methane. The team observed the permafrost for a total of seven years: an unprecedented long-term study.

What they found: without oxygen, equal amounts of methane and CO2 are produced. But since methane is a far more potent greenhouse gas, it is more significant. Because methane production couldn’t be measured, it was assumed that in the absence of oxygen only very small amounts of it can be formed. “It takes an extremely long time until stable methane-producing microorganisms develop in thawing permafrost,” explains Knoblauch. “That’s why it was so difficult to demonstrate methane production until now.”

The team has used the new data to improve a computer model that estimates how much greenhouse gas is produced in permafrost in the long term – and they’ve compiled a first forecasts. According to the soil scientist: “The permafrost soils of Northern Europe, Northern Asia and North America could produce up to one gigaton of methane and 37 gigatons of carbon dioxide by 2100.” But there are uncertainties. To what depth will the soil actually thaw by then? Will it be wet or dry? One thing, however, is certain: the new data will enable more accurate predictions about the impacts of thawing permafrost on our climate.

Knoblauch C, Beer C, Liebner S, Grigoriev M N, Pfeiffer E-M (2018): Methane production as key to the greenhouse gas budget of thawing permafrost; Nature Climate Change, DOI: 10.1038/s41558-018-0095-z

Picture download:

Collection of the samples

Christian Knoblauch with sample



Dr. Christian Knoblauch
Center for Earth System Research and Sustainability (CEN)
Universität Hamburg
+49 40 42838 2277

Stephanie Janssen
Presse- und Öffentlichkeitsarbeit
Center for Earth System Research and Sustainability (CEN)
Universität Hamburg
+49 40 42838 7596

The climate-conscious farmer

13. März 2018 - 12:57

In agriculture, there are various sources of greenhouse gases: tractors emit carbon dioxide, while cattle produce methane. The nitrogen in their liquid and dry manure is an effective fertilizer, but can also transform into nitrous oxide, which is 300 times as harmful to the climate as carbon dioxide. Around the world, whenever someone clears a forest, turns grasslands into pastures, or reduces the amount of humus in their crop soil, they harm the climate. In addition, aspects that may seem trivial can have real consequences: how often farmers till the soil, which crops they plant in which order, and whether they fertilize their soil when it’s wet or dry.

Starting in 2030, the still-forming “grand coalition” of political parties heading Germany’s federal government plans to obligate the agricultural sector to reduce emissions – just like the industrial sector is already forced to do. But who’s going to measure the emissions? Every field, every stall and sty is different; every management decision counts, and not even the farmers themselves can keep track of all the consequences. They do, however, consider the issue to be an important one: this was confirmed in the first survey of German farmers, which we conducted in connection with our research into greenhouse gases in agriculture.

First survey of German farmers on greenhouse gases

The majority of the 254 farmers surveyed rated their own level of knowledge in this area as comparatively low and wanted to receive further information. What’s more: the majority claimed they were willing to do their part to reduce emissions. We were surprised to see just how willing: 70 percent of those surveyed claimed that societal recognition would motivate them to run their farms in an environmentally friendlier manner. 40 percent even considered an emissions tax to be a good thing, most likely because it would affect all farms equally and therefore seemed fair to them. In return, the farmers expected to receive compensation, such as subsidies or a label for climate-friendly products, which could be used to justify charging higher prices.

Yet a tool that could show farmers exactly where the greenhouse gases come from, and how their individual choices affect emissions production, would also be an important aspect. It would need to be straightforward, lightweight and deliver results fast. And that’s exactly where we come in. We’re currently working to modify software that farmers already use – and to calculate emissions by drawing on data that they already collect. For example, sensors on their farm machinery already measure plant growth and indicators of crops’ nutrient supply. Using this data, the management software monitoring the sensors automatically measures the amount of fertilizer distributed, down to a scale of one square meter. If a mathematical model were added, the software could also calculate the amount of greenhouse gases produced. We’re now exploring the feasibility of this option at selected farms. Our vision is that, in the future, every farmer will have access to this additional software feature: first in Germany, and later throughout Europe.

Once that happens, farmers will be able to decide for themselves how to run their farms, where they can reduce emissions, and whether potential crop losses can be compensated for by financial remuneration. In turn, it will also be possible to define, review and implement climate targets for farmers.

This content was first published as a guest article in the newspaper Hamburger Abendblatt on 12th March 2018.

Uwe Schneider is an agricultural economist at Universität Hamburg.

Go to whole Abendblatt-series.

How cities shape the weather

8. März 2018 - 13:52

Urban climate is made up of factors like temperature, wind and humidity. Which is the most interesting?

For me it’s recently become the wind; it’s so changeable. It constantly surprises me when effects don’t occur where I expect them to: a gust of wind doesn’t sweep right around the corner, but instead releases its full force a few meters farther away.

Which is the most important weather factor?

For most people it’s the apparent temperature, which largely determines the comfort factor. We call this thermal comfort, and it mainly consists of air temperature, wind and the surface temperature of the ground and buildings together.

You study urban climate. How does this differ from the climate in the countryside?

When the prevailing “normal” weather in the countryside hits a city, most of the individual weather factors are affected. This is due to the buildings, patchy vegetation, and the characteristics of the various surfaces. Streets and buildings absorb heat during the day, and release that heat when the cooler evening comes. Unlike green areas, sealed surfaces can’t release cooling moisture through evaporation. At the same time, the corners of the buildings make the wind harsher, producing gusts.

In a recently published study, you investigate which urban effects are produced by cities themselves, and which are caused by global climate change, for instance. Why is it important to differentiate?

Once we know which climate change-related phenomena are intensified in cities, future urban planners will be able to implement targeted measures accordingly. But this aspect isn’t always easy to identify: when one of a city’s weather parameters changes, it also changes the other parameters – these are highly complex interactions. That’s why we’re working to clearly identify those factors that cities themselves influence.

Which weather factors fall into that category?

Wind, air temperature, humidity and surface temperature – in other words, factors that make up the thermal comfort – are all significantly changed by cities. In the summertime, the afternoons are much warmer in the city than they are in the surrounding countryside. For example, in Hamburg we record an average of 31 days per year with a high of over 25 degrees Celsius, but only 22 such days in the countryside. When it comes to hotter days, with a high of more than 30 degrees, the average number in the city is six per year – which is twice the number in the surrounding area. For people with health issues, the growing heat could mean real problems – and as climate change progresses, we’re likely to see more and more of these hot days.

Which weather factors aren’t affected?

When it comes to precipitation and hours of sunlight, we haven’t found any differences – at least not in your average major city in Central Europe, which Hamburg is a good example of. In China things can be a very different story; for example, in its metropolises the sunlight is limited due to heavy smog.

What can we do about urban heat if climate change continues?

Open bodies of water and greening efforts can produce a cooling effect; we should try to avoid adding more sealed surfaces. These aspects need to be directly addressed in the context of urban planning – which will improve citizens’ thermal comfort. At a higher level, the City of Hamburg can also help by reducing emissions and doing its part to achieve the globally agreed-upon climate protection goals.

Original article:
Sarah Wiesner, Benjamin Bechtel, Jana Fischereit, Verena Gruetzun, Peter Hoffmann, Bernd Leitl, Diana Rechid, K. Heinke Schlünzen, Simon Thomsen (2018): Is It Possible to Distinguish Global and Regional Climate Change from Urban Land Cover Induced Signals? A Mid-Latitude City Example; Urban Science 2 (1), 12

Enhanced weathering of rocks can help to suck CO₂ out of the air – a little

7. März 2018 - 17:06

“The Paris Agreement calls for a balance between anthropogenic greenhouse gas emissions by sources and removals by sinks in the second half of our century to keep global warming well below 2 degrees Celsius,” says lead-author Jessica Strefler from the Potsdam Institute for Climate Impact Research (PIK). “More than anything else this requires rapid and strong reductions of burning fossil fuels such as coal; but some emissions, for instance from industrial processes, will be difficult to reduce – therefore getting CO2 out of the air and storing it safely is a rather hot topic. The weathering of rocks, as dull as it might seem at first glance, is a scientifically exciting part of this.”

Hence the interest of assessing the economics of enhanced weathering for climate mitigation. Mining and grinding as well as transport and distribution were factored in. “Our calculations show that enhanced weathering could be competitive already at 60 US-dollars per ton of CO2 removed for dunite, but only at 200 US-dollars per ton of CO2 removed for basalt,” says Strefler. “This is roughly double of the carbon prices discussed in the current political debate, and substantially more than cost estimates for afforestation which are at 24 Euros per ton of CO2 removed. This is of course an important obstacle for any future implementation of enhanced weathering.”

India, Brazil, South East Asia, China seem to be the best suited locations

Strategies of carbon dioxide removal come with trade-offs. Planting huge numbers of trees to suck CO2 out of the air and store it in their trunks and branches for instance can come at the expense of land needed for food production. Also, carbon capture and underground storage (CCS) on an industrial scale is not accepted as safe by large parts of the population. Enhanced weathering, the spreading of rock material on land, may be easier to realize. However, dunite – the rock type most discussed amongst experts – contains harmful substances, such as chromium or nickel, that could get released during the process. This is why for the present study dunite is an important benchmark, but the researchers focus on basalt as a more sustainable option.

Current CO2 emissions are around 40 billion tons a year; natural weathering absorbs roughly 1.1 billion tons. Enhanced weathering could remove up to 4.9 billion tons per year if basalt is used, and up to 95 billion tons for dunite, according to the scientists’ calculations. It is likely, however, that in practice and considering all trade-offs, only a fraction of this potential could be realized. The best suited locations are warm and humid regions, particularly in India, Brazil, South East Asia, and China, where almost three quarters of the global potential could be realized. This is substantial, yet the uncertainties involved are also substantial, the scientists stress.

More than 3 billion tons of basalt needed to sequester one billion tons of CO2

“The annual potential of CO2 consumption is defined by the grain size and the weathering rate of the rocks used,” says Thorben Amann from Universität Hamburg’s Institute for Geology, Center for Earth System Research and Sustainability (CEN), he is also lead-author of the study. To sequester one billion tons of CO2, more than 3 billion tons basalt would have to be spread, a mindboggling amount equal to almost half of the current global coal production. Grinding the rocks and spreading the powder over roughly one fifth of global cropland would be necessary, which is believed to be feasible, but – due to the gigantic amount of rocks involved – the costs eventually add up.
“We can say that Enhanced Weathering is not just a crazy idea but could actually help climate policy, yet it is still a challenge to get a precise understanding of the involved processes,” says Amann. “After all, there will be impacts on the agricultural soils, their properties will change, but this can also be beneficial. Basalt for example can actually supply certain nutrients to soils, acting as a natural fertilizer.”

The assessment shows that enhanced weathering especially of basalt rocks could be an attractive option to support climate change mitigation, especially for tropical and subtropical regions, where the CO2 uptake potential is the highest. Yet, given the costs and the mass of rocks that would need to be moved, it can likely provide only a small additional contribution.

Press release by the Potsdam Institute for Climate Impact Research and Universität Hamburg, Center for Earth System Research and Sustainability (CEN)

Article: Jessica Strefler, Thorben Amann, Nicolas Bauer, Elmar Kriegler, Jens Hartmann (2018): Potential and costs of carbon dioxide removal by enhanced weathering of rocks. Environmental Research Letters [doi:10.1088/1748-9326/aaa9c4] (open access)

Weblink to the article

Dr. Thorben Amann
Universität Hamburg
Bundesstraße 55
20146 Hamburg
Phone: +49 40 42838-6676

For further information please contact:
PIK press office
Phone: +49 331 288 25 07

Zwei Preise und ein Exzellenzantrag – Jahresempfang von CEN und CliSAP

28. Februar 2018 - 14:05

Hintergrund ist, dass erst vor wenigen Tagen der Antrag auf Forschungsförderung für den Cluster „Climate, Climatic Change and Society“ – kurz CliCCS – im Rahmen der Exzellenzstrategie des Bundes eingereicht wurde. CEN Direktor Detlef Stammer berichtete den Gästen, wie ein wissenschaftliches Team dafür seit mehr als zwei Jahren eng zusammenarbeitete. Ab jetzt heißt es Warten und Hoffen: Auf die Bekanntgabe der bewilligten Förderungen Ende September 2018.

Anita Engels zeigte als Co-Sprecherin des Exzellenzclusters CliSAP, wie sehr sich die Zusammenarbeit über die Disziplinen hinweg verstärkt hat. Messbar wird dies über eine Analyse der Co-Autorenschaft aller wissenschaftlich begutachteten Publikationen innerhalb des Clusters der vergangenen zehn Jahre. Wie gelingt es, einander wissenschaftlich immer besser zu verstehen? „Wir schaffen viele Anlässe, um miteinander zu reden – auch wenn dies auf den ersten Blick Zeit kosten mag“, sagt Engels. Dass es sich lohnt, zeigt ein immer dichter gewobenes Netz gemeinsamer Publikationen aus ganz unterschiedlichen Forschungsfeldern.

Dr. Sascha Hokamp kam 2014 an die Forschungsstelle Nachhaltige Umweltentwicklung (FNU) der Universität. Er sitzt im Rollstuhl und stellte fest, dass es für wissenschaftliches Personal uniweit keine Schwerbehindertenvertretung gibt. Er half mit, diese aufzubauen und kümmerte sich unter anderem um die Ausstattung von Arbeitsplätzen, die Einweisung von Helfenden und geeignete Fluchtwege. Seit 2017 ist er hauptamtlicher Vertreter für das schwerbehinderte wissenschaftliche Personal der Universität. Für sein Engagement wurde Hokamp jetzt von Professorin Beater Ratter, Vorsitzende der CliSAP Gender Task Force mit dem Equality Award 2017 ausgezeichnet.
Mit einer herausragenden Dissertation gewann Dr. Christopher Hedemann den Wladimir-Peter-Köppen-Preis von CliSAP 2017 und das Preisgeld im Wert von 5000 Euro. Sein Doktorvater und Laudator Professor Jochem Marotzke erzählte beeindruckt von Hedemanns Forschung, die sich direkt in eine laufende Debatte zum so genannten Hiatus um das Jahr 2000 herum, eine Pause in der Erderwärmung, einmischte. Mit einer neuen und bemerkenswerten Methode identifizierte Hedemann, welche Regionen wie viel zum Hiatus beitrugen. Marotzke betonte das wissenschaftliche Gewicht der vorliegenden Arbeit und würdigte Hedemann als einen hervorragenden Preisträger. 

Pandora: Hope for Europe’s fish – and fishers

26. Februar 2018 - 12:57

Prof. Peck, the new research project is called “Pandora,” which stands for “Paradigm for Novel Dynamic Oceanic Resource Assessments.” But the name also conjures up images of Pandora’s box, which released a host of evils – did you consider this aspect?

There were certainly plenty of discussions when it came time to choose a name. We chose Pandora because the acronym is a good fit – and because it accurately reflects the level of complexity involved in our work. In many parts of the world, the fishing industry has a poor reputation because there is so much overfishing. But the very last thing that came out of Pandora’s box was hope – and that’s something people shouldn’t forget.

What is the project’s most important goal?

We plan to collate the available data on European high-seas fishing and develop computer models that deliver more accurate projections on the development of fish stocks. The models will then be made freely available via an online platform. Our vision for the future is as follows: fishers can enter information on which species they plan to catch, and which quantities, into the model – and receive immediate feedback on whether they’re fishing sustainably or overfishing. The models can also potentially help them consider alternatives, e.g. whether it might be wiser to concentrate on other species for a time.

What do the new models offer that previous models don’t?  

Pandora’s computer models will take into account far more parameters. For example: currently, fish species are generally assessed and managed individually. But this ignores important interactions. For instance, cod eat herring, and herring in turn eat cod eggs. As a result, the catch quota set for any given species automatically affects other species. Pandora will provide models that are capable of displaying these interrelationships.

Many fish stocks have actually grown over the past several years, and this aspect, too, impacts other species. So you can see that Pandora is being launched at an exciting time: there are now more fish in the ocean again, and we need new methods to effectively manage them.

Is all of the required data already available?

No, we’re still lacking data on some regions. In some cases, we still don’t know enough about the stocks – where the fish swarms are, or their exact makeup. Particularly in the Mediterranean, where many stocks are now struggling, there are major gaps. As such, one of Pandora’s central goals is to improve collaboration between the scientific community and fishing industry; that’s what we here in Hamburg are responsible for.

At the beginning, you mentioned overfishing. Isn’t this problem due to an overly greedy fishing industry – and catch quotas that are much too high? How can a project like Pandora help?

The fishing industry has dramatically – and permanently – changed marine ecosystems. We can’t turn back the clock. But the industry isn’t interested in catching every last fish possible; it understands what’s happened to the stocks. Now science is working for the industry, in that we want to help make fishing more sustainable. So science and the fishing industry aren’t enemies; they need to work hand in hand. In this regard Pandora will offer workshops for fishers, which will also help get valuable data from them. Convincing them of the need to avoid overfishing isn’t always easy, but by the same token, most of them know the current state of the fish stocks better than anyone else.  

A further important aspect of Pandora will consist in providing political actors the best possible scientific basis for decision-making. But once we’ve done so, the political machinery will take over from there. And the quotas that result are often just as puzzling to researchers as they are to the fishing industry. But they’re political decisions, after all.  

Prof. Myron Peck also coordinates the CERES project, in which researchers are investigating the effects of climate change on aquacultures and the fishing industry. For more on CERES, visit:
Climate Change: Hyperactive oysters and stressed carps

The energy transition: When maize fields become a bone of contention

13. Februar 2018 - 12:39

The transition to climate- and environment-friendlier energy sources is impacting our landscape: wind turbines and energy crops for biogas plants require a great deal of space – which can lead to conflicts. Accordingly, at Universität Hamburg’s Center for Earth System Research and Sustainability (CEN) we are currently investigating what future “energy landscapes” could look like. To do so, my colleague Prof. Jürgen Scheffran and I are working with models that simulate developments over extended timeframes. For example, we use what are known as agent-based models – models that describe why, when and how stakeholders act.

Concretely, we have employed such a model in Schleswig-Holstein to investigate how bioenergy needs are shaping land use. Here, every agricultural community is considered to be a stakeholder. We’ve also taken a closer look at four agricultural plants that can, in part, be used as energy crops – wheat, maize, sugar beets and winter rapeseed – and compared the size of the crop fields and the choice of plants in 2010 with the projected development through 2100.

The idea: farmers in each community make decisions about which plants to grow every year on the basis of specific rules. That means they don’t act randomly, but instead take into account the current profit expectations – making them to some extent predictable. The market price, harvest size and demand can be used to calculate the potential profit for farmers.

When it comes to the price and harvest size, in the model we assume that the trends of the last 20 years will continue largely unchanged; in contrast, we vary the other factors for each respective case. In this way we can e.g. investigate how crops change when more agricultural land is available, or what happens when energy crops are actively promoted, such as through subsidies.

The results show: if communities have more available agricultural land each year, the area used for food production doesn’t decline. What’s more, the proportion of energy crops, including maize – which typically partly serves as an energy crop – declines and instead, above all, more wheat is planted. Only external stimuli, like financial incentives, can increase the proportion of energy crops. However, beyond a certain point this development accelerates markedly – changing the landscape significantly.

Our model is unbiased: it shows which developments can arise, but not people’s reactions, for example protests. We can, however, identify situations in which conflicts are likely – for instance when monocultures are created, or when commercial land competes with conservation areas. If residents respond with e.g. demonstrations, it could affect farmers’ decisions for or against particular plants – and the development through 2100 would then look very different.

At the annual “Energielandschaften Norddeutschland” conference (Energy Landscapes North Germany) we bring together representatives from government, the scientific community and society at large to discuss different scenarios and issues. Together we seek to find solutions and to assess new developments. For example: What would change if bioenergy were no longer limited to local use, but could be used throughout Germany? Would more farmers opt for maize if there were also a demand for it as an energy crop in Bavaria?

This content was first published as a guest article in the newspaper Hamburger Abendblatt on 13th February 2018.

Dr. Peter Michael Link is a geographer at Universität Hamburg’s Center for Earth System Research and Sustainability.

Go to whole Abendblatt-series

Der Wert der Statistik für die Klimaforschung

1. Februar 2018 - 11:08

Der globale Klimawandel ist wieder in den Medien präsent: Der amerikanische Präsident hat angekündigt, dass die USA den Pariser Klimavertrag der Vereinten Nationen aufkündigen werden. Dieser Vertrag hat zum Ziel, die globale Klimaerwärmung auf höchstens zwei Grad Celsius, besser noch auf 1,5 Grad, zu begrenzen. Donald Trump und Teile seiner Regierung leugnen die Existenz der globalen Klimaerwärmung. Andere Teile der US-Regierung, vor allem das Militär, nehmen den Klimawandel und seine Sicherheitsrisiken dagegen sehr ernst.

Erwärmung seit 1975 deutlich angezogen

Das Klima hat sich bereits erwärmt. Dies wissen wir durch Analysen von Wetterbeobachtungen und Klimamodellsimulationen. Die Statistik ist dabei eine der bedeutendsten Erkenntnisquellen der Klimaforschung. Denn obwohl wir geographisch und zeitlich niemals vollständige Messdaten haben werden, können wir mit Hilfe der Statistik diese fehlenden Daten ermitteln. So lassen sich aktuelle und frühere Zustände des Klimasystems darstellen und zukünftige Entwicklungen einordnen. 

Die globale Erwärmung berechnen wir Klimaforscher aus der so genannten global gemittelten Temperatur der Erdoberfläche. Dieser Wert ergibt sich aus dem Durchschnitt aller vorhandenen Temperaturdaten von Land- und Ozeanoberfläche zu einem bestimmten Zeitpunkt. So zeigt sich zum Beispiel, dass 2016 das bisher wärmste Jahr seit Beginn der Temperaturaufzeichnungen war. Die globale Temperatur lag mit 0,94 Grad Celsius beinahe ein Grad über dem Mittelwert des gesamten 20ten Jahrhunderts. Gleichzeitig hat die Erwärmung seit 1975 deutlich angezogen: Zwei Drittel des Temperaturanstiegs passierten in den letzten 40 Jahren, wobei es jedes Jahrzehnt 0,15 bis 0,2 Grad Celsius wärmer wurde. Durch statistische Analysen dieser Zeitreihe lässt sich der Klimawandel also bestimmen und quantifizieren. 

Solch ein globaler Mittelwert für die Temperatur ist hilfreich, da er komplexe Änderungen in einer einzelnen Zeitreihe erfasst. Mit bloßem Auge lässt sich die Erwärmung des Klimas ablesen. Aber die Zeitreihe enthält auch Unsicherheiten. Ursache dafür ist zum Beispiel ein unterschiedlich dichtes Netz von Messstationen. Es gibt sehr viele Wetterstationen in Europa und den USA, aber recht wenige in Afrika oder den polaren Regionen. Die Ozeantemperatur kann wiederum nur in Regionen mit regelmäßigem Schiffsverkehr flächendeckend erhoben werden. Doch gerade in der Arktis, von der kaum Messdaten vorliegen, steigen die Temperaturen am schnellsten. 

Trump: Klimawandel in New York 2014 nicht zu spüren

Mit statistischen Methoden können wir die Temperatur in solchen Regionen abschätzen. Diese Rechnungen beinhalten Unsicherheiten. Doch sie lassen sich exakt beziffern und werden wiederum in die folgenden Rechnungen einbezogen. So erhalten wir einerseits den wahrscheinlichsten Temperaturwert an einem Ort und gleichzeitig auch die Spannbreite seiner möglichen Abweichung. Die Spannbreite ist dabei ein Maß für das Vertrauen in den ermittelten Temperaturwert: Je enger die Spanne ist, umso näher kommt der Wert der Realität. 

Dies ist ein großer Vorteil der Statistik. Auch wenn wir mit Wahrscheinlichkeiten rechnen, können wir alle Unsicherheiten systematisch berücksichtigen. So wird stets deutlich, welcher Wert wie sicher ist. Die Statistik erlaubt uns, dies ganz genau zu quantifizieren. Zurück zum Trump-Tweet: Wenn er beklagt, den Klimawandel im New Yorker Juli 2014 nicht zu spüren, hat er durchaus Recht. Denn die mittlere globale Temperatur ist kaum geeignet, das lokale Wetter zu beschreiben. Obwohl wir erwarten, dass bis zum Jahr 2100 die Temperaturen weltweit ansteigen werden, wird dieser Anstieg nicht überall gleichmäßig verlaufen. Denn unser Klimasystem ist räumlich und zeitlich sehr variabel. 

In einigen Regionen kann es zunächst sogar kühler werden. Meeresströmungen zum Beispiel haben einen starken Einfluss auf die Temperatur der Erdoberfläche. Sie unterliegen aber gleichzeitig natürlichen Schwankungen: Temperatur-Rhythmen von Jahrzehnten bis zu Jahrhunderten. Diese Schwankungen treten unabhängig vom menschengemachten Klimawandel auf. In einer Kaltphase des Ozeans würden sie deshalb die globale Temperaturerhöhung abschwächen – also maskieren. Eine Warmphase würde den Klimawandel dagegen verstärken. So können immer wieder kalte Sommer und verschneite Winter auftreten, die einer globalen Erwärmung gefühlt widersprechen. Die Statistik sagt uns, dass solche Ereignisse durch den Klimawandel immer weniger wahrscheinlich werden, aber nicht unmöglich sind. 

Stärke und Einfluss der Schwankungen lassen sich schwer abschätzen

Um den Trend von natürlichen Klimaschwankungen zu trennen benutzen wir das Signal-zu-Rauschen-Verhältnis. Die globale Erwärmung selbst bezeichnen wir dabei als Signal. Als Rauschen überlagern die natürlichen Klimaschwankungen dieses Signal. Zurzeit dominiert das Signal, also der Klimawandel, vor allem auf der globalen Skala das Geschehen. Regional und lokal bestimmt dagegen immer noch vorwiegend das Rauschen, also die natürlichen Schwankungen, unser Klima – auch wenn sich lokal durchaus schon Veränderungen zeigen. In Zukunft werden die vom Menschen verursachten Klimaänderungen jedoch immer eindeutiger aus dem Rauschen hervortreten, bis sie es schließlich komplett dominieren. Mit Hilfe der Statistik können wir auch dies beschreiben. 

Doch woher wissen wir, welche Schwankungen natürlich sind? Viele natürliche Veränderungen des Klimas, wie zum Beispiel Dürreperioden, wirken auf sehr langen Zeitskalen. Manche Phasen hängen mit der Ozeanzirkulation zusammen und laufen über viele Jahrzehnte. Es gibt jedoch erst seit rund 1850 ausreichend Messwerte hierzu. Stärke und Einfluss dieser Schwankungen lassen sich also nur schwer abschätzen. Mehr Informationen aus unserer Klimavergangenheit liefern uns hingegen Proxy-Daten. Hier verraten Baumringe, Korallen, Pollen, Eisbohrkerne aber auch historische Schriften indirekt etwas über die Temperaturen in der Vergangenheit. Alle diese Daten werden statistisch ausgewertet, so dass wir eine historische Temperaturzeitreihe der letzten 12000 Jahre erstellen können.

So können wir den Klimawandel im Kontext natürlicher Schwankungen über einen sehr langen Zeitraum betrachten: Die Temperatur ist heute nicht nur höher als jemals in den letzten 12000 Jahren, die Erwärmung ist auch außerordentlich rasant vor sich gegangen. Vor allem die Geschwindigkeit macht Sorgen, denn Ökosysteme und Gesellschaften können sich nur langsam an neue Klimabedingungen anpassen.

Modelle und Experimente belegen menschliche Einflüsse

Doch wie stark beeinflussen natürliche Schwankungen das Klima im Vergleich zum Menschen? Mit komplexen Rechenmodellen lässt sich unser Klima auf Hochleistungscomputern simulieren. Diese Modelle beschreiben mit Hilfe physikalischer und chemischer Gesetze das Klimasystem möglichst genau. So simulieren wir zum Beispiel ein heutiges Klima mit dem Treibhausgas Niveau von vor der Industrialisierung um 1750. In einem anderen Szenario erhöhen wir die Menge an Treibhausgasen so, wie sie heute tatsächlich vorliegt. Vergleichen wir beide, so zeigt sich deutlich, dass nur mit den zusätzlichen vom Menschen verursachten Emissionen die heute messbare Temperaturerhöhung erreicht werden kann. Ohne den Einfluss des Menschen wäre es heute im Schnitt rund ein Grad Celsius kühler.

Manche Leugner des Klimawandels behaupten weiter, dass Kohlendioxid, auch als CO2 bezeichnet, gar nicht auf das Klima wirkt. Doch schon um 1896 belegte Svante Arrhenius (1859-1927) im Labor, wie wirksam CO2 als Treibhausgas ist – und sagte den Treibhauseffekt recht genau vorher. Er errechnete, dass eine Verdoppelung von CO2 in der Atmosphäre die Temperatur um vier Grad erhöhen würde. Heute gehen wir von einer Erhöhung zwischen 1,5 und 4,5 Grad Celsius aus. Arrhenius Prognose liegt also am oberen Ende der Klimamodellvorhersagen, aber im Bereich des Möglichen. Mit einfachen grundlegenden Überlegungen kam er also schon vor mehr als 100 Jahren zu realistischen Vorhersagen.

Methode der Anti-Klima-Lobby

Der Begriff Unsicherheit suggeriert, dass Forscher sich ihrer Ergebnisse nicht sicher sind. Dies ist aber nicht der Fall. In der Statistik beschreibt der Begriff eben die Spanne innerhalb derer sich die Ergebnisse bewegen. Mit Hilfe der Statistik stellen wir eindeutig fest, dass sich in den letzten 150 Jahren das Klima schneller erwärmt hat als jemals zuvor. Und wir können belegen, dass dies auf das Konto der Menschen geht. Der amerikanische Präsident und andere Entscheider leugnen den globalen Klimawandel, obwohl es dafür keinen einzigen wissenschaftlichen Grund gibt. Ich bezeichne sie deshalb als Leugner – und nicht als Skeptiker.

Wissenschaftlich gesehen sind die Ursachen des Klimawandels geklärt wie ich dargelegt habe. Das Ziel der Leugner ist nicht die wissenschaftliche Debatte voran zu bringen und unser Verständnis des Klimasystems zu verbessern, sondern Zweifel in der Bevölkerung zu säen. Die Leugner, es sind nur sehr wenige aber sie gehen sehr aggressiv vor, übertreiben die Meinungsunterschiede in der wissenschaftlichen Diskussion damit die Bevölkerung sich fragt: Wenn sich die Experten uneinig sind warum sollen wir dann unseren Lebensstil ändern und der Staat viel Geld in den Klimaschutz investieren? Die Leugner wollen den falschen Eindruck erwecken, dass die Ursachen des Klimawandels noch nicht geklärt sind.

Die Leugner greifen dabei auf Methoden, und auch Lobbyorganisationen zurück, die schon die Tabakindustrie angewandt hat, um den Zusammenhang zwischen Rauchen und Lungenkrebs zu diskreditieren. Später wurden so auch die wissenschaftlichen Erkenntnisse zwischen schwefelhaltigen fossilen Brennstoffen (Kohle, Erdöl und Erdölprodukte) und dem „Sauren Regen“(und auch zwischen Fluorchlorkohlenwasserstoffen und dem Ozonloch) in Zweifel gezogen, obwohl zu den jeweiligen Zeitpunkten die wissenschaftlichen Ursachen geklärt waren; unter anderem durch statistische Analysen.

Dieser Artikel ist zuerst im Wissenswert-Journal Anfang 2018 erschienen. (Ausgabe 2/2017)

Mehr von Christian Franzke:

Europa wird wärmer, Türkei kühlt sich ab

One Year of Climate Change on Twitter – One Year of Trump Arousing Attention?

30. Januar 2018 - 11:32

The analysis of the online media monitor (OMM) reveals that the number of climate change-related tweets has risen compared to 2016. Still – and this year even more – Donald Trump’s statements and action trigger most Twitter communication on climate change. This year’s highest peaks of attention were related to climate political events in the USA. Most tweets were published on 2nd June 2017, one day after US-president Donald Trump declared that the USA will quit Paris climate agreement.

The second most discussed event was Trump’s order to review Obama’s clean power plan, in which he lifted the ban on coal leases and discarded expert thinking on true cost of carbon emissions. The third event triggering climate change related tweets was the inauguration of Donald Trump as US-president. In contrast, other political events like the climate summit in Bonn received only little attention.

Besides events from the political sphere, also extreme weather events like Hurricane Harvey in August and Hurricane Irma in September triggered a huge amount of climate change-related tweets. One peak of Twitter communication in August 2017 was provoked by the release of a scientific report which concludes that Americans already feel the effects of climate change. This means that also scientific events have the potential to trigger debate, although in 2017 mainly political issues seem to have caused communication. Generally, it bears mentioning that almost exclusively US-American events received a lot of attention. This is remarkable against the backdrop that the online media monitor does not only capture tweets with the hashtags or key words #climatechange or “climate change” or “global warming”, but also the German word “Klimawandel”.

The online media monitor also analysed the domains climate change-related tweets link to, i.e., which sources they use. A look to the Top 10 domains reveals that most tweets link to other tweets or other content published on Twitter, e.g. photos. Apart from that, journalistic news websites are the main source of reference. Especially the British newspaper “The Guardian” plays a leading role, followed by other rather liberal and progressive outlets like the “New York Times”, “The Independent” and “Washington Post”.

Interestingly, conservative news outlets only appear in the Top 20 sources of reference, e.g. Breitbart. Not only classic journalistic outlets, but also innovative journalistic websites are among the Top 10 sources, e.g. “Inside Climate News” – a Pulitzer Prize-winning, non-profit, non-partisan news organization dedicated to covering climate change, energy and the environment, or “Thinkprogress”, an editorially independent news site of the Center for American Progress Action Fund. Interestingly, also the hybrid outlet “Climatecentral” belongs to the Top 10 sources of reference. It is edited by leading scientists as well as journalists researching and reporting facts about climate change and its impact on the public.

The online media monitor (OMM) provides ongoing monitoring of the transnational online media debate on climate change by searching for related tweets. For already two years, the OMM collects Tweets if they contain the following hashtags or key words: #climatechange OR “climate change” OR “global warming” OR “Klimawandel”. Additional criteria are that the tweets got at least 5 retweets and contain at least one link.

Köppen Prize 2017: Dr. Christopher Hedemann

29. Januar 2018 - 13:12

At the beginning of the 21st century, temperatures on the Earth rose less sharply than expected – despite increased CO2 emissions and continuing climate change. This raised the question: what happened to the extra heat? 

To date, scientists have assumed that the oceans “swallowed” the extra heat and stored it in their depths. However, Christopher Hedemann has demonstrated that the total amount of heat absorbed by the global oceans was not sufficient to explain the slowdown in warming. Instead, he has identified a further possible cause. Using numerous climate models, he has demonstrated that in certain phases, the Earth reflects more of the sun’s energy, so that less heat reaches its surface. This process also slows the temperature rise.

This means that different causes for the slowing of global warming come into question: heat absorption by the oceans, increased reflection of the sun’s energy – or a combination of the two. It’s impossible to calculate which of these factors was responsible for the slowdown between 1998 and 2012 using the data currently available.

By awarding the Köppen Prize to Christopher Hedemann, the jury has honored an original dissertation that goes beyond critically assessing the methods used in connection with a tangible phenomenon and pushes the epistemological limits of climate research and modeling. “The work shows that science advances often stem from calling earlier findings into question,” explains the jury.

The Cluster of Excellence CliSAP awards the Wladimir Peter Köppen Prize for outstanding doctoral theses by young scientists. The prize, worth €5,000, will be presented for the ninth time at CliSAP’s annual reception on February 23, 2018.

More information about the Köppen Prize

Online learning for climate studies

29. Januar 2018 - 12:19

As a “Massive Open Online Course” – or MOOC for short – the course was part of a first-semester introductory seminar in the international degree program. Prior to starting the course, many students were skeptical: after all, they already had a broad background in the natural sciences, so how was the MOOC supposed to offer them new insights?

“Especially the social sciences and socioeconomic parts of the course were completely new to me,” enthuses Ji hye Jeong, whose statement reflects the experience of many students. In contrast, the natural sciences lessons were less challenging for many students, as had been expected. Overall, the MOOC offered an excellent overview of the current state of research. “What I liked best was that so many current examples were used in the course,” adds Joana Kollert, another Master’s student.

“With the climate MOOC, our climate research association has for the first time dared the leap from communication to education,” says Marie-Luise Beck from the German Climate Consortium (DKK), which jointly designed the online course with the WWF. Further, the new English-language edition is particularly well suited for use at universities around the globe. “The discussion showed us that users’ needs can vary considerably. For our students, the chapters on the social and business sciences were particularly difficult; for members of the general public, the natural sciences sections are often the hardest.  Thanks to the MOOC’s modular structure, the content can easily be adapted to the specific audience,” explains Beck. The students’ overall feedback was crystal clear: the online course should continue to be part of the first-semester curriculum.



The climate MOOC

In the online course, some of Germany’s leading climate researchers convey a basic grasp of climate change – clearly and concisely. Among others, many researchers from the Cluster of Excellence for climate research CliSAP participated:

Together they explain the causes and effects of climate change, and how its impacts can be mitigated. The course is tailored to those individuals seeking deeper insights into the subject matter, e.g. students, instructors and academic researchers, climate protection and energy managers, companies that wish to do their part in protecting the environment, political decision-makers and journalists. In addition to addressing the scientific fundamentals, it discusses various options for taking remedial action. Register free of charge, and find further information.

The North Sea – portrayed by 300,000 data sets

25. Januar 2018 - 11:23

Taking up industrial and agricultural wastewater from all across the country tributaries such as the Elbe and Weser are pushing their way into the sea. Likewise, large quantities of car and power plant emissions pumped into the air are dissolving into the ocean. Thus, ample amounts of additional—potentially unwanted—nutrients like phosphate and nitrogen reach the North Sea contributing to overfertilization.

Luckily, ever since phosphates were banned from detergents in the 1980s, phosphorous concentrations have declined; nitrogen levels are also dropping. The European Union Water Framework Directive (WFD) as of 2000 sets limit values for both. Nonetheless, during peak times these maximums are far exceeded, for instance through land fertilization.

At the Center for Earth System Research and Sustainability (CEN) my colleague Johannes Pätsch and I share a particular interest in finding out how the North Sea will change in the future: What nutrient concentrations can be found and how will they be distributed in coastal waters and the open sea? What are the impacts of climate change and rising temperatures?

30 years ago, water used to contain substantial amounts of nitrogen

We are using a computational climate model that can provide detailed prognoses for the North Sea Region. Based on mathematical formulas it is geared to deliver simulations, as exact as possible, of the complex processes at work there. We verify our results by modeling previous time periods and comparing them with real-world data gathered at the time. The more similar the results, the better the model.

But the data set best fitting our model merely comprises measurements from the 1970s to the 1990s. It is rather ill-suited for a comparison with today, as back then the water was still full of phosphate and nitrogen. So, we needed a new data set aiming to collect and prepare all official data gathered on the North Sea Region from 1960 to date and make it available all across the world—a giant project.

Initially, I asked various oceanographic research centers for daily figure packages including times and places. These centers receive most data from research vessels, measuring buoys or coastal stations. I thus accumulated over 300,000 data sets with information on salt concentration, temperatures at various water depths, and nutrients such as phosphate, nitrogen, and silicate—all meeting different standards and quality levels.

New sewage treatment or less exhaust emissions – which approach is more effective?

From this we had to eliminate double mentions, identify freak values, and check data plausibility. We used the cleansed data to develop an interactive map of the North Sea with measured values for each month. Our map is freely accessible online through the University’s Integrated Climate Data Center (ICDC)—a treasure trove for marine biologists and climate modelers.

The new data is already helping us detect weak spots in our computational model. During simulations, for example, the phosphate value never fully drops to zero. In the sea, however, this frequently happens once all nutrients get used up in summer. We must therefore further hone our model until it gets better at simulating real conditions. As soon as it can simulate the past 30 years as targeted it will be fit for calculations into the future. Our next goal is to predict North Sea scenarios up to the year 2100.

Such prognoses are in high demand. What is the key to reducing nutrient loadings? New wastewater treatment plants? Nitrogen-free car fumes? Policymakers strive to comply with EU-prescribed limits. Our improved North Sea model helps devise useful countermeasures.


This content was first published as a guest article in the newspaper Hamburger Abendblatt on 17th January 2018.

Iris Hinrichs is an oceanographer at Universität Hamburg.

Go to whole Abendblatt-series

Link to full new data set (North Sea Biogeochemical Climatology - NSBC)

How do mangroves protect our climate?

24. Januar 2018 - 14:57

Mangroves, salt-water tolerant trees with characteristically high root systems, grow all along the coast of the South Pacific island of Fiji. Yet the data we have on how these mangrove forests store carbon is sparse. Fiji, the Pacific nation taking the lead in climate change, is at pains to close this gap. Burkhart Brielmeier and Sarah Reimer, two master’s students in wood science at Universität Hamburg, spent 4 months in Fiji in order to develop a method for recording the biomass of mangrove forests and evaluating their carbon-storage capacity.

What was the aim of your stay on Fiji?

Burkhart Brielmaier: To develop a method enabling us to create an inventory of the mangrove forests on Fiji so that we can calculate their capacity to store carbon. To do so, we had to record the biomass within pre-defined areas.

Sarah Reimer: A further task was to familiarize the local forestry officers and students with our method so that, in theory, the inventory can continue without our being present and it will be possible to carry out a national mangrove inventory.

What does it mean to “record biomass”? What does that entail?

BB: In our research, we work with so-called transects and we only take into account the wooden biomass above ground: that means no leaves and no roots under the soil. 4 months would be far too short for recording an entire plant. The sample areas in the transects measure 3 x 3 meters each, with a distance of 50 meters between each sample area.

SR: The most widespread mangrove species Rhizophora spp. grows like a weed. At most locations, it was impossible to say where the tree started and ended. This mangrove species also entwines itself with other trees and doesn’t develop a true trunk. That is why it is not possible to determine the number of trees per area, as we would do in a conventional inventory.

For this reason, we used a method known as “destructive sampling.” Basically, we documented our sample areas and then we chopped them up and weighed them. Instead of using measuring the volume, we evaluated density to estimate the wooden biomass. Once we have the biomass, we can then calculate the level of carbon.

And why is it useful to know how much carbon is stored in mangroves?

BB: In the Kyoto Protocol as well as at the Cop23, the UN Climate Change Conference in Bonn , and many other climate change meetings, the leading industrial nations have promised to help developing countries with climate change.

If, for example, the German federal government would like to support mangrove conservation on Fiji, we first need to know more about the importance of the mangrove forests. Without well-founded knowledge of the positive effects on the climate, no money will flow.

SR: Moreover, mangrove forests are a very important ecosystem: They purify water, transport biomass into the ocean—which is important for corals—and provide us humans with medicines or firewood. They also serve many fish species, such as sharks, as a breeding ground. And because they prevent erosion, they are also very important for coastline conservation.

What exactly did you have to do on a daily basis to achieve this?

SR: The social aspect plays a very important role. On Fiji, as on other Pacific islands, communities are governed by the “chief system.” This means that you need to introduce yourself in the village to whom the mangrove forest belongs. This takes place in a ritual called the Sevu Sevu, in which you state your intentions and offer a kava root. If the chief accepts the kava root, then you have been accepted as a member of the village and are free to carry out whatever you stated. Most of the time the chief gave us a boat with a guide who took us to our sample areas.

And who instructed you to do this project?

BB: Professor Dr. Michael Köhl from wood science asked us if we were interested. He has contacts in the German development agency GIZ (Gesellschaft für internationale Zusammenarbeit GmbH). Our project was part of the REED+ Program (Reducing Emissions from Deforestation and Forest Degradation and the role of conservation, sustainable management of forests and enhancement of forest carbon stocks in developing countries).

Fijian mangroves or central European mixed forests—what is your favorite?

BB: It is difficult to compare the two. Central European mixed forests are subject to heavy commercial use and are far removed from their natural states. Conversely, the mangroves build a highly sensitive ecosystem and are largely untouched by humans. Here nature has adapted to the most extreme conditions. And as such, working in the mangroves is an extreme experience. The tropical climate, the mosquitos, and the musty smell of the muddy ground add a particular flavor to our work: an Eldorado for any adventurer.



Prof. Dr. Michael Köhl
Faculty for Mathematics, Informatics and Natural Sciences
Department of Biology
Center for Wood Sciences
World Forestry
Tel: +49 40 73962-100
Website Holzwirtschaft

This article was first published here: Universität Hamburg

Global climate change conferences: sending an important signal

18. Dezember 2017 - 14:58

Can global conferences slow climate change? Following the failure of the 15th United Nations Climate Change Conference (COP15) in Copenhagen in 2009, the negotiations seemed to have reached a standstill. But the COP21 in 2015 produced a new global climate agreement, the Paris Agreement, which was hailed as a major victory. And just a few weeks ago, the COP23 in Bonn drew to a close, without a binding agreement but with a sea of happy faces. How can we measure the success of climate conferences?

Together with international colleagues, in 2015 I closely followed the negotiations for the COP21 in Paris and analyzed them from a sociological perspective. With more than 30,000 participants and 150 heads of state at the opening ceremony, the conference was characterized by many superlatives. Our focus wasn’t on the outcome, the Paris Agreement, but on the negotiations and the diverse events that took place during the conference.

The main work done at the conference in Paris was surprisingly unspectacular: in groups, the text was broken down clause by clause. Every suggested amendment was discussed and subsequently implemented in the text – or wasn’t. Given the diverse range of interests, this was a lengthy undertaking. And the resulting Paris Agreement is fundamentally different from its predecessor, the Kyoto Protocol from 1997. First of all, it defines two common goals: helping poorer countries adapt to the impacts of climate change, and limiting global warming to less than two degrees Celsius. Yet it leaves the question of how to achieve these goals up to the individual states, relying on voluntary commitments and regular progress reports. In contrast, the Kyoto Protocol clearly delineated the required emissions reduction for each respective country.

Yet, as important as they are, the resulting agreements alone don’t make for successful conferences. The effects produced by climate conferences also concern the negotiating process itself: different countries work together to find a mutually acceptable text, while vying with NGOs, environmental protection and business associations over whose interpretation has the most weight. As a result, year after year a large community sends governmental and business actors a clear signal that they’ll need to adjust their future plans accordingly. Ideally, this promotes climate-friendly developments. For example, some of the countries that met in Bonn have now announced plans to abandon coal energy.

The most important outcome of our analysis: it’s only when thousands of people with disparate backgrounds come together to discuss and work on new resolutions that a meaningful basis is formed for identifying shared problems and potential solutions. Climate conferences serve to network the relevant actors, and to reinforce the importance of climate change in our collective awareness. At these events, we can witness the first steps toward forming a global society.  

But is that enough? Of course not. The Paris Agreement shows a potential way forward, but is based on voluntary participation. And we can quite readily see from lessons recently learned in Germany – e.g. with plans for sustainable mobility or phasing out coal-based energy production – that such plans can provoke major resistance. Major changes like making our economy a more sustainable one clearly can’t just be dictated “from the top down”; without constant grass-roots pressure, global pledges will remain nothing more than empty promises. As such, if we hope to mitigate climate change to a tolerable level, it’s civil society that has to now step up to the plate.

This content was first published as a guest article in the newspaper Hamburger Abendblatt on 11th December 2017.

Stefan Aykut is a Junior Professor of Sociology at Universität Hamburg.

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„Research in Germany“: CEN und CliSAP präsentieren Forschung in den USA

14. Dezember 2017 - 16:36

„Das Interesse an deutscher Klima- und Erdsystemforschung ist groß“, berichtet Ute Kreis, zuständig für die CliSAP/CEN Öffentlichkeitsarbeit. „Junge Wissenschaftlerinnen und Wissenschaftler suchen nach neuen, spannenden Projekten und Karrieremöglichkeiten. Andere fragen gezielt nach bestimmten Forschungsgebieten und sprechen uns auf mögliche Kooperationen an. Und natürlich sind auch die Bemühungen Europas, insbesondere Frankreichs, um Klimaforschung und Klimaschutz hier Thema.“

Am Stand in der Exhibitors Hall können sich Besucherinnen und Besucher über geowissenschaftliche Forschung in Deutschland, aktuelle Vorhaben und Karriereoptionen informieren. Neben CEN und CliSAP präsentieren sich hier auch die norddeutschen Exzellenzcluster Future Ocean und MARUM sowie das GFZ Helmholtz-Zentrum Potsdam, verschiedene Transregio Programme und Sonderforschungsbereiche.

Noch bis Ende der Woche ist der Messestand Kontakt- und Anlaufstelle für Kolleginnen und Kollegen, Nachwuchstalente und Partner aus der ganzen Welt. Auch Alumni, ehemalige und zukünftige Gastwissenschaftlerinnen und Gastwissenschaftler treffen sich hier. „Für uns ist die Präsenz auf der AGU eine tolle Plattform, um Kontakt aufzunehmen“, so Forschungskoordinatorin Martina Bachmann, „Exzellente Voraussetzungen, um die internationale Zusammenarbeit zu stärken.“