Ever thought of that as a challenging mode: Plauge and Famine?
You can even adopt The Plague (the Black Death) from Rhye's and Fall of Civilzation, which displays a near-perfect display of The Plauge.
From 1347 to 1351, the Black Death, a massive and deadly pandemic originated in Central Asia, swept through Asia, Europe and Africa. It may have reduced the world's population from 450 million to between 350 and 375 million.[15] China lost around half of its population, from around 123 million to around 65 million; Europe around 1/3 of its population, from about 75 million to about 50 million; and Africa approximately 1/8th of its population, from around 80 million to 70 million (mortality rates tended to be correlated with population density so Africa, being less dense overall, had the lowest rate). This makes the Black Death the largest death toll from any known non-viral epidemic. Although accurate statistical data does not exist, it is thought that 1.4 million died in England (1/3 of England's 4.2 million people), while an even higher percentage of Italy's population was likely wiped out. On the other hand, Northeastern Germany, Bohemia, Poland and Hungary are believed to have suffered less, and there are no estimates available for Russia or the Balkans. It is conceivable that Russia may not have been as affected due to its very cold climate and large size, hence often less close contact with the contagion.
The Black Death contributed to the destruction of the feudal system in Medieval Time. As more slaves and workers died, there were fewer people to work for the nobles and they had to give higher wages to the workers willing to work on the nobles' lands. The Black Death also killed many great kings and nobles. In its aftermath, the Black Death may also have favoured the use of more advanced farming tools as a smaller workforce was available and plots grew larger as a result of the population loss.
The Black Death continued to strike parts of Europe sporadically until the 17th century, each time with reduced intensity and fatality, suggesting an increased resistance due to genetic selection.[14] Some have also argued that changes in hygiene habits and efforts to improve public health and sanitation had a significant impact on the falling rates of infection.
-Wikipedia
As for Famine which is a more severe, but more isolated part of the world should be placed randomly across the world. I was thinking it of temperarly severly reducing your food storages by a large margin in a few cities (like 3 or 4).
A famine is a widespread shortage of food that may apply to any faunal species, which phenomenon is usually accompanied by regional malnutrition, starvation, epidemic, and increased mortality.
Although most famines coincide with regional shortages of food, famine in some human populations has occurred amid plenty or on account of acts of economic or military policy that have deprived certain populations of sufficient food to ensure survival. Historically, famines have occurred because of drought, crop failure, pestilence, and man-made causes such as war or misguided economic policies. Bad harvests, overpopulation, and epidemic diseases like the Black Death helped cause hundreds of famines in Europe during the Middle Ages, including 95 in the British Isles and 75 in France.[1][2]
During the 20th century, an estimated 70 million people died from famines across the world, of whom an estimated 30 million died during the famine of 1958–61 in China. The other most notable famines of the century included the 1942–1945 disaster in Bengal, famines in China in 1928 and 1942, and a sequence of famines in the Soviet Union, including the Holodomor, Stalin's famine inflicted on Ukraine in 1932–33. A few of the great famines of the late 20th century were: the Biafran famine in the 1960s, the disaster in Cambodia in the 1970s, the Ethiopian famine of 1983–85 and the North Korean famine of the 1990s.
Famine is typically induced by a human population exceeding the regional carrying capacity to provide food resources. An alternate view of famine is a failure of the poor to command sufficient resources to acquire essential food (the "entitlement theory" of Amartya Sen), analyses of famine that focused on the political-economic processes, an understanding of the reasons for mortality in famines, an appreciation of the extent to which famine-vulnerable communities have strategies for coping with the threat of famine, and the role of warfare and terrorism in creating famine. Modern relief agencies categorize various gradations of famine according to a famine scale.
Many areas that suffered famines in the past have protected themselves through technological and social development. The first area in Europe to eliminate famine was the Netherlands, which saw its last peacetime famines in the early 17th century as it became a major economic power and established a complex economic organization. Noting that many famines occur under dictatorship, colonial rule, or during war, Amartya Sen has posited that no functioning democracy has suffered a famine in modern times.
-Wikipedia