Christian Rohr

This paper focusses on historical climate impact research, one of the branches of historical climatology with an emphasis on the Little Ice Age. It provides examples of the theoretical concepts, models, and further structuring considerations that are used in historical climate impact research, which are especially fitting to the examined period. We distinguish between the impact of climate on society by timescale in long-term, conjunctural or medium-term, and short-term impacts. Moreover, a simplified climate-society interaction model developed by Daniel Krämer is presented, as well as the concept of the Little Ice Age-type Impact (LIATIMP) by Christian Pfister and the vulnerability concept regarding climatic variability and extreme weather events. Furthermore, the paper includes a state-of-the-art application of the historical climate impact research and discussion of research gaps. Cuando el tiempo se volvió malo. La investigación de los impactos del clima en la sociedad y la economía durante la Pequeña Edad del Hielo en Europa RESUMEN. Este trabajo se centra en el estudio del impacto histórico del clima, una de las ramas de la climatología histórica, en este caso en relación con la Pequeña Edad del Hielo. Proporciona ejemplos de conceptos teóricos, modelos, y consideraciones estructurales que se emplean en la investigación histórica del impacto climático. Distinguimos el impacto del clima en la so-ciedad a distintas escalas, a largo plazo, coyuntural o a medio plazo, y a corto plazo. Por otro lado, se presenta un modelo simplificado de interacción clima-sociedad desarrollado por Daniel Krämer, así como el concepto de im-pacto del tipo de la Pequeña Edad del Hielo de Christian Pfister y el concepto de vulnerabilidad en relación con la variabilidad climática y el impacto his-tórico del clima y de los eventos extremos. Finalmente, el trabajo incluye una actualización de la investigación sobre el impacto histórico del clima y una discusión acerca de las lagunas de investigación existentes.

Severe climatic anomalies in summer 1816, partly due to the eruption of Tambora in April 1815, contributed to delayed growth and poor harvests of important crops in Central Europe. Coinciding with adverse socioeconomic conditions, this event triggered the last subsistence crisis in the western World. Here, we model reductions in potential crop yields for 1816 and 1817 and address the question, what impact a similar climatic anomaly would have today. We reconstructed daily weather for Switzerland for 1816/17 on a 2 km grid using historical observations and an analogue resampling method. These data were used to simulate potential crop yields for potato, grain maize, and winter barley using the CropSyst model calibrated for current crop cultivars. We also simulated yields for the same weather anomalies, but referenced to a present-day baseline temperature. Results show that reduced temperature delayed growth and harvest considerably, and in combination with reduced solar irradiance led to a substantial reduction (20%–50%) in the potential yield of potato in 1816. Effects on winter barley were smaller. Significant reductions were also modelled for 1817 and were mainly due to a cold late spring. Relative reductions for the present-day scenario for the two crops were almost indistinguishable from the historical ones. An even stronger response was found for maize, which was not yet common in 1816/17. Waterlogging, which we assessed using a stress-day approach, likely added to the simulated reductions. The documented, strong east-west gradient in malnutrition across Switzerland in 1817/18 could not be explained by biophysical yield limitations (though excess-water limitation might have contributed), but rather by economic, political and social factors. This highlights the importance of these factors for a societies' ability to cope with extreme climate events. While the adaptive capacity of today's society in Switzerland is much greater than in the early 19th century, our results emphasize the need for interdisciplinary approaches to climate change adaptation considering not only biophysical, but also social, economic and political aspects.

Zusammenfassung «Unerwartete Wildtiere» in den Alpen. Heuschreckeneinfälle und ihre Folgen für die Ostalpen im Mittelalter und in der frühen Neuzeit Die Heuschreckenschwärme stammten zumeist aus der Ungarischen Tiefebene und fielen in der Folge in die Alpentäler in der Steiermark, in Kärnten sowie in Nord-und Südtirol ein. Die Berichte in zeitgenössischen Chroniken des 13. bis 16. Jahrhunderts machen deutlich, dass die Menschen in den Ostalpen die Heuschreckenplagen als göttliche Strafe und als Vorzeichen des Jüngsten Gerichts interpretierten. Die Beschreibungen der Heuschrecken folgen dabei eng den Erwähnungen derselben in der Bibel (Exodus, Joel, Offenbarung et cetera). Allerdings scheint der tatsächliche ökonomische Schaden nicht so verheerend gewesen zu sein, da die Heuschrecken zumeist erst im August den Ostalpenraum erreichten, als die Ernte schon eingebracht war. Die Reak-tionen und Abwehrmassnahmen waren vielfältig: Larven wurden gesammelt und verbrannt; tote Tiere wurden begraben und fliegende Heuschrecken versuchte man durch Lärmschlagen daran zu hindern, sich auf dem Boden niederzulassen. Zudem wurden Prozessionen abgehalten, um Gnade bei Gott zu erflehen, ja, mitunter griff man sogar zu magischen Praktiken und versuchte die Heuschrecken rituell zu bannen.