In the scientific landscape, diversity isn’t just a buzzword; it’s a fundamental ingredient for innovation. The 4th km-scale hackathon hosted in Hamburg by the nextGEMS project exemplified this mindset, bringing together over 130 participants from institutions in Africa, Asia, Europe, and North America. From March 4th to 8th, 2023, professionals with particular backgrounds, levels of expertise, and from 16 different countries converged to further develop the existing Earth System models used in nextGEMS, as well as extrapolating current and past data to create future scenarios.

Participants at the Hamburg hackathon.
Group of participants working together at the Hamburg hackathon.

Matias Olmo, a Postdoctoral Researcher at the Barcelona Supercomputing Center, reflected on the unique opportunity the hackathon presented to integrate new scientists into the community, especially those who, like him, were attending for the first time. Specifically, he highlighted how helpful the event was to increase his understanding of how to use high-resolution data.

Similarly, Stephy Libera, a Research Assistant at the Earth and Life Institute from Louvain Catholic University (UC Louvain), highlighted the casual encounters facilitated by the hackathon gatherings. For her, it was advantageous „meeting people from different projects altogether and seeing that there are so many colleagues working on similar, complementary, and parallel topics.“ Additionally, Libera contributed as part of the European Eddie-Rich ESMs (EERIE) project – one of the projects co-organizing the hackathon – and shared a brief insight into the work she will be doing as part of EERIE after the hackathon: the effects on mesoscale eddies underneath sea ice, starting with the sea ice in the Antarctic and later in the Arctic.

Indeed, the essence of a hackathon isn’t solely measured by the quantity of scientific output, as Quan Liu, a Postdoctoral Researcher from the Climate Variability Department at Max Planck Institute for Meteorology, emphasized. For him, „the idea of the hackathon is more about making people work together, which somehow helps transfer coding skills in a very practical and useful way to younger scientists”.

Other participants advanced with their modelling endeavors during the event, like Alejandro Uribe, a Postdoctoral Researcher at the Meteorological Department of Stockholm University. His work during the hackathon was focused on the intricate dynamics of precipitation efficiency within specific regions, shedding light on the model’s fidelity in reproducing real-world phenomena. Furthermore, he shared how, compared to previous hackathons, the provided support and information on-site and through the nextGEMS website enabled him to „analyze and access data easier, avoiding wasting too much time in technicalities and using that time for analysis and for thinking“.

With each participant bringing a unique perspective and expertise to the table, the hackathon served as a melting pot of ideas, propelling Earth System Modeling and Climate Science forward. At the same time, the event demonstrated the power of collaboration, diversity, and community in scientific work.

With a sunny morning in Hamburg (Germany), more than 130 participants attending the nextGEMS 4th km-scale Hackathon gathered at the Max Plack Institute for Meteorology (MPI-Met) on Friday, March 8th for the closing session. It started at 9:00 am, providing a space for the different thematic groups – Storms & Ocean, Storms & Land, Storms & Radiation, and Storms & Society – to share their observations, analysis, and first hacking results with everyone.

Participants at the closing hackathon session in the MPI.
Participants starting the closing session day.

Postdoctoral Researcher at the MPI-M, Arjun Kumar, summarised outcomes from the Storms & Ocean breakout groups. For instance, it was found that the Arctic sea-ice holes in the ICON model – an issue that was at the center of attention during the last days -were caused by an error, whereby the ocean does not lose momentum to the sea ice. The role of ocean eddies and tropical cyclones on the carbon cycle were also explored in a novel one-year simulation with ocean biogeochemistry. Other topics included global vertical eddy heat fluxes; tropical precipitation biases; ocean mixing; the spatial scales of air-sea interactions; and declining fish stocks in the West African coast.

On behalf of the Storms & Land group, Postdoctoral Researcher at the University of Bern, Edgar Dolores Testillos, talked about the runs made with the IFS model. The team observed more frequent atmospheric blockings in different regions of the world, like the North Pacific. An atmospheric blocking indicates that the normal west-to-east flow of the air current in the upper levels of the Earth’s atmosphere (or jet stream) is disrupted or “blocked”. Consequently, they prolong the periods of certain weather conditions regionally, like heatwaves or heavy rainfalls, which makes blockings a crucial phenomenon to understand in climate modeling and weather forecasting due to its impact on ecosystems, agriculture, and society.

Thorsten Mauritsen talking at the hacktahon.
Thorsten Mauritsen talking about the Storms & Radiation hacking results.

On another note, Thorsten Mauritsen, Researcher and Professor at University of Stockholm, shared the results from the Ocean & Radiation team, which was diversely integrated mostly by participants from outside the nextGEMS project. A highlight from the presentation were the haboobs (or sand storms) formations in the Sahara region, which were displayed in an astonishingly graphical way for the audience. Other aspects observed with the ICON model covered the low level of clouds in the Southern Ocean, and the distribution of areas where atmospheric conditions lead to the formation and release of precipitation – known as precipitation cells – that are reaching the Sahara region.

The  Storms & Society team, represented by Researcher at Barcelona Supercomputing Center, Eulália Baulenas, explained how during the hackathons knowledge is translated into action. Furthermore,  she shared the visual output that the group worked on to co-produce videos with Latest Thinking, as well as the preparation of a policy brief on km-scale modeling, which is currently in its beginning stage. Before finalizing, an important announcement was made by Project Coordinator, Heike Konow, about the future nextGEMS hackathon: it will happen in the city of Wageningen, in the Netherlands, from the 14th-18th of October 2024.

Heike Konow holding a presentation about the hackathons.
Heike Konow holding a presentation about the nextGEMS hackathons.

Lastly, as a final wrap-up, the hackathon community converged its knowledge in the final discussion panel, led by Bjorn Stevens, Managing Director of the MPI-Met. During this dialogue, the participants had the opportunity to address concerns about the Earth system models, the outputs, and the climate data, as well as ideas for future collaborative scientific publications and experiments.

March started, and our nextGEMS hackathon too! On Monday 4th, approximately 129 participants arrived at the ravishing building that houses the Max Planck Institute for Meteorology (MPI-Met), in the port city of Hamburg, in Germany. The 4th km-scale Hackathon, co-organized by three climate science projects (nextGEMS, EERIE, and WarmWorld), welcomed professionals from different scientific backgrounds, levels of expertise and diverse nationalities, representing a variety of institutions.

The hackathon opened up with a set of introductory talks. Bjorn Stevens, welcomed everyone and encouraged the attendants to seize the event as an opportunity to learn from each other. After some logistic information provided by one of the nextGEMS Project Coordinators, Elina Plesca, the updates on the Earth System models used in the nextGEMS and EERIE projects started. Scientific Programmer at the MPI-Met, Dian Putrasahan, talked about how the hackathon could help us understand how smaller scale ocean features like eddies could affect ocean circulation, carbon fluxes and storms. Additionally, one breakout group will explore and gain insights as to why sea-ice holes appear in our simulations.

Our engaged participants listening to the introductory talks

As part of the Storms & Society segment of the project, researcher Eulàlia Baulenas shared with the audience how this nextGEMS fragment is trying to reduce the gap between climate research and tangible action. Moreover, the team announced the launching of a survey that will contribute to understand knowledge networks and their interactions during the hackathon. It will be available online from Wednesday, March 6th.

On another note, the Hamburg-based science communication company with expertise in Film, Design and IT, Latest Thinking, stressed the importance of transmitting scientific knowledge and research through explanatory videos. Especially, as an effort to reach audiences in the policy-making fora. The hackathon continued with a captivating keynote executed by Daniela Jacobs, meteorologist and Director of the Climate Service Center in Germany (GERICS). She highlighted the importance of relying on and utilizing data already gathered and documented by climate institutions in the completion of new research (more on this talk will be released in a separate blogpost). 

IFS Introduction Talk held by Thomas Rackow

To finish the first hackathon day, the participants enjoyed an “Ice-Breaker” session, where they were able to catch-up and exchange their thoughts about the intense hacking days ahead.

From the 4th to the 8th of March 2024, the portuary city of Hamburg (Germany) will host our upcoming 4km-scale Hackathon. This is the fourth hackathon of the nextGEMS project, and this year it will be co-organized by two other climate modelling projects: European Eddy-Rich ESMs (better known as EERIE) and WarmWorld. The event will mainly take place in the Max Plack Institute  (MPI) for Meteorology, and some sessions will happen in the buildings of the University of Hamburg, the Geomatikum, and the Pharmacy building.

As an exploratory hacking marathon – commonly known as a hackathon, our event will bring together professionals and experts from a wide variety of areas within the climate science field to find and fix bugs in the existing models and work on extrapolating current and past data to create future scenarios. Overall, the 4km-scale hackathon will provide an environment where the participants can programme, model, collaborate, and exchange ideas.

In addition to the model development during the hacking periods, the occasion will also supply a space for the diffusion of knowledge. Daniel Klocke and Thomas Rackow will talk about the Earth System models used in nextGEMS: ICON and IFS – respectively. Moreover, there will be two keynotes: one by the meteorologist Daniela Jacobs about the Earth Visualisation Engines (EVE) for climate initiative, and another by Climate Physics Director at MPI, Sarah Kang, about the possible shift in mechanistic controls of tropical Pacific surface warming pattern. In case you were not already hooked by that, two special side events will also take place with the immersive experience of visiting the Wind Tunnel at the University of Hamburg and the DKRZ supercomputer Levante.

All the information about the venue, transportation, accommodation, programme, and getting ready is gathered online on the hackathon’s official website. In case you are interested in our previous hackathons, you are able to find more information about them on the nextGEMS official website. Furthermore, we will be giving live updates about the event on our Mastodon and LinkedIn accounts, so don’t forget to follow us and stay tunned! Do you have further questions? Then we are happy to answer them via email at and in person at the event!

This will be the 4th km-scale hackathon. After three previous hackathons, mainly organized under the nextGEMS project, our hackathons now become even bigger. This time the km-scale hackathon will be co-organized by three projects: EERIEWarmWorld, and nextGEMS.

Please join us for one week of hacking, finding bugs, fixing bugs, and a lot of fun from 4th to 8th March 2024 in Hamburg, Germany.

In the spirit of what was written in our proposal, participants will sit together in small groups working on a topic. The topics will be related to the four nextGEMS research themes, as well as to marine ecosystem and fisheries Challenge Problem. We will all explore those topics based on the newest simulations of the IFS and ICON models, identify bugs and improvements. If you haven’t been to a hackathon, have a look at our Cycle 1, Cycle 2, and Cycle 3 hackathons to get an impression of the atmosphere and collaboration.

Continuing the tradition of the previous hackathons, we are also opening a call for stipend applications to support the participation to the 4th km scale hackathon. Go here for more details.

If you are interested in participating in the Hackathon, please register here until the 1st of January, 2024.

The event will charge a EUR 150 participation fee. Once your participation is confirmed, you will also receive the instructions for the payment.

Please visit the event page for more details about the hackathon.

For any additional questions, please contact the nextGEMS project office at


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