Upcoming Talks

Es spricht: Moritz Drupp (UHH)

Abtract folgt

Es spricht: Stephen Sitch, University of Exeter

In this presentation I will first give a broad overview of the role of the terrestrial ecosystems in the contemporary global carbon cycle, and ecosystems mitigate climate change already today. A key question relates to the efficiency of land ecosystems to sequester CO2 and how it will change in the near-term future, e.g. can it help us achieve the Paris agreement to avoid dangerous climate change. To begin to answer this question we first need to understand processes and regional attribution of the contemporary land carbon sink, e.g. the relative contribution of changing atmospheric composition, climate and land-use change to the land sink dynamics. I will draw upon research conducted using the TRENDY ensemble of land models which supports the annual Global Carbon Budget. I will highlight recent work in boreal and tropical forests and dryland ecosystems, and the role of cascading effects of deforestation on the land sink. Finally, I present work on how land-use emissions play a critical role in land-based mitigation for Paris climate targets.

Es spricht: Christopher Kadow, DKRZ

Climate change research today relies on climate information from the past. Historical climate records of temperature observations form global gridded datasets that are examined, for example, in IPCC reports. However, the datasets combining measurement records are sparse in the past. Even today, they contain missing values. We found that recently successful image inpainting technologies, such as those found on smartphones to get rid of unwanted objects or people in photos, are useful here. The derived AI networks are able to reconstruct artificially cropped versions in the grid space for any given month using the missing values observation mask. So herewith we have found with AI a technique that gives us data from the past that we never measured with instruments.  Other important datasets used in the Assessment Report 6 of the IPCC to study climate change, as well as advanced applications such as downscaling in atmosphere and ocean, a hybrid (AI&ESM) data assimilation approach within ICON, or precipitation in broken radar fields are shown in this presentation.

Climate research, including the study mentioned in the previous paragraph, often requires substantial technical expertise. This involves managing data standards, various file formats, software engineering, and high-performance computing. Translating scientific questions into code that can answer them demands significant effort. The question is, why? Data analysis platforms like Freva (Kadow et al. 2021, e.g., gems.dkrz.de) aim to enhance user convenience, yet programming expertise is still required. In this context, we introduce a large language model setup and chat bot interface based on GPT-4/ChatGPT, which enables climate analysis without technical obstacles, including language barriers. This approach is tailored to the needs of the broader climate community, which deals with massive data sets from kilometer-scale modeling and requires a processing environment utilizing modern technologies, but addressing society after all - such as those in the Earth Virtualization Engines (EVE eve4climate.org).

Kadow, C., Hall, D.M. & Ulbrich, U. Artificial intelligence reconstructs missing climate information. Nat. Geosci. 13, 408-413 (2020). https://doi.org/10.1038/s41561-020-0582-5

Kadow, C., Illing, S., Lucio-Eceiza, E. E., Bergemann, M., Ramadoss, M., Sommer, P. S., Kunst, O., Schartner, T., Pankatz, K., Grieger, J., Schuster, M., Richling, A., Thiemann, H., Kirchner, I., Rust, H. W., Ludwig, T., Cubasch, U., and Ulbrich, U.: Introduction to Freva – A Free Evaluation System Framework for Earth System Modeling, Journal of Open Research Software, 9, p. 13, https://doi.org/10.5334/jors.253, 2021

Es spricht: Louis Kotzé (THE NEW INSTITUTE)

The Anthropocene signifies the start of a no-analogue trajectory of the Earth system that is fundamentally different from the Holocene. This new trajectory is characterized by rising risks of triggering irreversible and unmanageable shifts in Earth system functioning. We urgently need a new global approach to safeguard critical Earth system regulating functions more effectively and comprehensively. The global commons framework is the closest example of an existing approach with the aim of governing biophysical systems on Earth upon which the world collectively depends. Derived during stable Holocene conditions, the global commons framework must now evolve in the light of new Anthropocene dynamics. This requires a fundamental shift from a focus only on governing shared resources beyond national jurisdiction, to one that secures critical functions of the Earth system irrespective of national boundaries. We propose a new framework—the planetary commons—which differs from the global commons framework by including not only globally shared geographic regions but also critical biophysical systems that regulate the resilience and state, and therefore livability, on Earth. The new planetary commons should articulate and create comprehensive stewardship obligations through Earth system governance aimed at restoring and strengthening planetary resilience and justice.

Es spricht: Da Yang, University of Chicago

Conventional wisdom suggests that warm air rises while cold air sinks. However, recent satellite observations show that, on average, rising air is colder than sinking air in the tropical free troposphere. This is due to the buoyancy effect of water vapor: the molar mass of water vapor is less than that of dry air, making humid air lighter than dry air at the same temperature and pressure. Unfortunately, this vapor buoyancy effect has been considered negligibly small and thereby overlooked in large-scale climate dynamics. Here we use theory, reanalysis data, and a hierarchy of climate models to show that vapor buoyancy has a similar magnitude to thermal buoyancy in the tropical free troposphere. As a result, cold air rises in the tropical free troposphere. We further show that vapor buoyancy enhances thermal radiation, increases subtropical stratiform low clouds, favors convective aggregation, and stabilizes Earth’s climate. However, some state-of-the-art climate models fail to represent vapor buoyancy properly. This flaw leads to inaccurate simulations of cloud distributions—the largest uncertainty in predicting climate change. Implications of our results on paleoclimate and planetary habitability will also be discussed.