ES1.8

How to cite: Goddard, C. and Fung, F.: Co-produced storylines of climate hazard uncertainty for the heritage sector, EMS Annual Meeting 2022, Bonn, Germany, 5–9 Sep 2022, EMS2022-372, https://doi.org/10.5194/ems2022-372, 2022.

Storylines provide a way to communicate climate change and especially changes in extreme events in a tangible way for the public and decision makers by putting the focus on associated risks and impacts. In this work, storylines are created for the 2003 summer heatwave in Switzerland. For this purpose, an analogous event is searched for in the already existing Climate Scenarios for Switzerland (CH2018). This event shall be as extreme in the future climate as 2003 was in its time. Building storylines for this future extreme event, we demonstrate how a 2003-like summer might be like by the end of the Century assuming no climate change mitigation. Specific indicators are chosen to develop four individual heat-related storylines and enabling a direct comparison between 2003 and the future hot summer. For the future summer, the number of hiking weather days in the Alps is projected to increase on the one hand, while on the other hand also fire danger increases massively. More and longer heatwaves may aggravate heat-related health issues and additional generations of agricultural pests could threaten agricultural yields.

With these storylines of a similar future heatwave, we gain a better understanding of locally relevant processes, get insight into how extreme events quantitatively change with the warming climate, give examples of possible impacts, and finally try to stimulate public awareness for possible consequences of future climate change. We explore different ways of visualizing and communicating the results, which may find broader application to inform Swiss stakeholders about future climate change and its possible impacts.

How to cite: Mastai, A., Wehrli, K., Kotlarski, S., and Fischer, E.: Storylines of future climate extremes in Switzerland, EMS Annual Meeting 2022, Bonn, Germany, 5–9 Sep 2022, EMS2022-469, https://doi.org/10.5194/ems2022-469, 2022.

Offering climate services to the wind energy industry is not without its challenges. Users are curious about the potential impacts of climate change on their projects. While estimates of wind resources are based on historical assessments, many questions arise. What if 20 years of past data is not enough to sample the internal variability of the site? Will the long term average wind speed change beyond the margins already taken into account in the project design? Will extreme speeds change in such a way that design parameters will no longer be valid? Very often, however, these users are reluctant to use information, specifically time series, that cannot be “correlated” with their onsite measurements.

In this presentation we describe our journey as a climate services SME, in search of tools and approaches that we could use not only to provide robust information to these users, but also information that they could trust and eventually incorporate in their decision making. 

In particular, we focus on a use case building storylines for a concrete wind development target area. These storylines are built as  plausible future conditions that are consistent with the current climate projections, and at the same time maximally sample their uncertainty. Our storylines provide a rationale not just to estimate the potential impacts of climate change on wind resources, but also to understand the mechanisms driving these changes and the robustness of the climate model projections. Additionally, being conditioned on for instance, different levels of global warming, they provide the wind resource scenarios that can be fed into climate risks analysis now being required by new sustainability regulations, such as the ‘EU taxonomy for sustainable activities’.  

Faced with the challenge of providing uncertain climate change information to users strongly tied to observation-driven reconstructions of climate conditions, we believe that these storylines offer an opportunity to facilitate the adoption of climate change information by a range of users, from the technical experts doing the energy assessment, to the management in charge of strategic decisions.

How to cite: Lopez, A. and Lizcano, G.: Building storylines for wind resources: our experience with users, EMS Annual Meeting 2022, Bonn, Germany, 5–9 Sep 2022, EMS2022-494, https://doi.org/10.5194/ems2022-494, 2022.

Europe is the major chocolate manufacturer in the world. With a market value of 40 billion euros, the sector not only serves the continent’s internal chocolate demand but supplies most of the world, accounting for more than 76% of global chocolate sales. Yet the sector is highly dependent on imports of chocolate’s main ingredient, cocoa, from beyond Europe, mainly from West Africa. This dependency means that the sector is vulnerable to climate extremes, and possible climate change impacts, that occur in cocoa exporting regions. This study uses the climate storyline approach to build links between extreme climatic events occurring in two major West African cocoa exporting countries and their potential consequences on European society and its economy. It aims to provide cross-border climate risk information to the chocolate industry in Europe.

The climate storyline approach is inspired by a drought event in West Africa in 1983, which resulted in cocoa production losses of up to 60% in the region. Consequently, cocoa prices spiked and there was a shortage of supply which affected prices for both chocolate producers and consumers in Europe. The storyline approach includes a modeling chain of these events, i.e., the impacts of the drought on cacao yields and cocoa production in the exporting region; consequent changes to the trade volume between the region and Europe, and to cocoa prices; and the cascading economic impacts of these changes on the wider chocolate industry. Furthermore, drought impacts on cacao yields and cocoa production under future climatic conditions are determined for the periods 2021-2040, 2041-2060 and 2081-2100 under RCP 2.6, 7.0 and 8.5 scenarios. Next, the storyline modeling chain is applied to the future climatic conditions to reveal how climate change in West Africa could impact European society and its economy, with a particular focus on chocolate manufacturing.

How to cite: Ercin, E., Kaune, A., and Karaman, C.: A climate storyline approach to inform private sector decisions on cross-border climate risks:A case study of the chocolate industry in Europe, EMS Annual Meeting 2022, Bonn, Germany, 5–9 Sep 2022, EMS2022-416, https://doi.org/10.5194/ems2022-416, 2022.

In the June of 2009 central Europe witnessed a rampant rainfall spell that spread across populated areas of the country. High-intensity rainfall caused 3000+ landslides in the southeastern Austrian state of Styria, and property damages worth €10 Million. Elsewhere in Austria, flooding amounted to reparations worth €40 Million. Numerous synoptic-scale studies indicated the presence of a cut-off low over central Europe and excessive moisture convergence behind the extreme event. In a warmer climate change scenario, such an extreme precipitation event may manifest into a more intense event due to the higher water holding capacity of air with increased temperatures, but this reasoning may not be so straightforward considering the complex physics of precipitation, more so in a topographically heterogeneous region such as the GAR (Greater Alpine Region).

The flooding and landslides caused in the region raise an alarm and thus motivate this study whereby we investigate if the rainfall event did become stronger with time due to climate change compared to how it would have been in a counterfactual (climate change free) past. Here we have deployed the CCLM high-resolution regional model coupled with a statistical landslide model to simulate this event (rainfall and landslides) in a pseudo (surrogate) warming scenario. A marked decrease in rainfall intensity is observed in the simulations for a 1 K cooler climate (pre-industrial past) and the consequent landslide risk could reduce by up to 20%. In the future,  depending on the changes in rainfall and soil moisture, the area affected during a 2009-type event could grow by 45% at 4 K global warming, although a slight reduction is also possible.

In this novel event-based study, we discuss the results from the lens of attribution perspective - how conditional attribution is much more useful compared to the conventional risk-based approach of attributing extreme events. We develop physical storylines to address the increasing risks of landslides in the region.

How to cite: Mishra, A. N., Maraun, D., Knevels, R., Truhetz, H., Bevacqua, E., Proske, H., Petschko, H., Leopold, P., Brenning, A., Zappa, G., and Schaffer, A.: Storylines: A severe rainfall-landslide event in Past, Present & Future climate scenarios, EMS Annual Meeting 2022, Bonn, Germany, 5–9 Sep 2022, EMS2022-313, https://doi.org/10.5194/ems2022-313, 2022.