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Climatic extremes triggered migration

Freiburg researchers publish study into emigration from Southern Germany in the 19th Century

Freiburg, Nov 17, 2017

Climatic extremes triggered migration

German emigrants boarding a ship to New York City/USA around 1850. Source: Wikimedia Commons

More than five million Germans emigrated to North America in the 19th Century, many from the south of Germany. They fled from poverty, war and revolution – and from massive climatic variations. As a study by Prof. Dr. Rüdiger Glaser, Dr. Iso Himmelsbach and Annette Bösmeier from the Institute of Environmental Social Sciences and Geography at the University of Freiburg shows, these variations were one of the key causes of the waves of migration from the region that is now the Federal State of Baden-Württemberg to North America. The researchers hope that their study will contribute to the discussion about the causes of migration, as experts are forecasting mass migrations on account of future climate changes. The study has been published in the specialist journal “Climate of the Past” of the European Geosciences Union.

“We found that climate explains up to 20-30 percent of migration from Southwest Germany to North America in the 19th century,” says lead author Rüdiger Glaser. The Year Without Summer, 1816, was wet and cold causing widespread crop failures, and eventually famine and emigration. It followed a year after the eruption of the volcano Mount Tambora on Indonesia, its ash and gas spreading through the atmosphere and causing temperatures to drop around the world for several years.

The team’s study has now shown that the subsequent five waves of migration in the following decades were influenced by climatic extremes. For instance, migration also peaked in 1846, when a hot and dry summer caused the harvest to fail. “The chain of effects is clearly visible: poor climate conditions lead to low crop yields, rising cereal prices and finally emigration,” explains Glaser. The team studied official migration statistics and population data from the 19th century, as well as weather data, harvest figures and cereal-price records.

Climate was a less significant factor in driving the largest emigration wave, from 1850 to 1855, Glaser and his team found. During the Crimean War (1853–1856), for example, France banned food exports, putting pressure on the German grain markets.


Original publication: Glaser, R., Himmelsbach, I., and Bösmeier, A.: Climate of migration? How climate triggered migration from southwest Germany to North America during the 19th century, Clim. Past, 13, 1573–1592, doi:10.5194/cp-13-1573-2017.

Interview on Glaser’s research in the University magazine uni’leben (2015)


Prof. Dr. Rüdiger Glaser
Institute of Environmental Social Sciences and Geography
University of Freiburg
Tel.: +49 (0)761 203-3527