Great divergence in climate change adaptation during 1500-1900AD: A comparative study on social resilience of Germany and China from a food security perspective

The effectiveness of adaptation to climate change depend on the social resilience. Historical case studies of climate change adaptations would be conducive to better understanding the preferred solution of people with different cultural background, and coping with the risk of the ongoing global climate changes. The relationship among climate change, adaptations and social resilience are analyzed based on the previous researches about famines, agricultural production, trade and migration in Germany during the 16th to the early 20th century. Differences in the primary choices and their effectiveness between Germany and China are also discussed from the perspective of food security. The results are as follows. (1) In the 16th and 17th centuries, the German agricultural system was quite sensitive to the cold and abrupt fluctuated climate, and poor harvests always accompanied by famines in which more than 30% were severe famines. After 1700AD, the severity of famine and its correlation with temperature declined gradually. About 29% famines were merely considered as dearth, and the only severe famine (1770-1772AD) occurred after a back-to-back harvest failure. However, the impact of rainfall extremes on harvest still existed. (2) Germany successfully escaped from famine after 1850AD due to four effective adaptations: ① Planting structure adjustment, like increasing the proportion of rye, was first thought of, but the effectiveness was limited until potatoes became widely accepted. ② The rapid increase in crop yield brought by ago-technology progress reversed the trend of social resilience decreasing with population growth, but was not enough to fully offset the impact of climatic deterioration. ③ The degree of dependence on grain import reached 20% in a short time, which improved the food availability and reduced the famine risk in German mainland. ④ Three emigration waves, following the drought (1844-1846AD) and cooling (1870-1890AD) might have partly alleviated food shortage, especially at a local scale. By 1900AD, German social resilience was nearly 20 times than the scenario of lacking adaptation. (3) In contrast to Germany entered a resilience increasing period since the early 18th century, China maintained the decline of resilience as population pressure increased. Differences might be attributed to their location and culture background. China had long been a unified and powerful empire in east Asia with large internal market and self-sufficient agricultural society, which made it more prone to reduce risk through domestic adjustments, such as internal migration and government relief. When the capacity for disaster relief efforts by the government failed to meet the needs of crisis management, social resilience would drop dramatically. Whereas Germany, located in the continent with a long history of division and amalgamation, had a commercial tradition and was close to the origin of the first industrial revolution, was more willing and likely to find new approaches for food supply ensurance or risk transfer in regional exchanges.