232 climate and geography: The Islamic World Climate Along with a diversity of landscapes comes a wide variation in Europe’s climate The climate of eastern Europe is generally cold and dry because it is dominated by Arctic air masses sweeping down from Siberia Western Europe has moderate temperatures, heavier rainfall, and longer growing seasons Both eastern Europe and western Europe have the familiar four seasons of spring, summer, fall, and winter But the southern peninsulas, which are surrounded by the Mediterranean, share the climate of North Africa and Western Asia, with two seasons: hot, dry, agriculturally unproductive summers and cool, rainy winters that allow a crop to be planted The climate of western Europe is noteworthy, especially for its fluctuations during the Middle Ages Western Europe is far warmer than other areas of the earth at similar latitudes The reason for this begins with a tropical current that flows from Africa toward South America The current is deflected up the coast of the American continents and returns eastward in the form of the Gulf Stream, a wind-driven current that goes about as far as the island of Bermuda The tremendous amounts of warm water delivered by the Gulf Stream continue until it washes up against the shores of western Europe because of a mechanism known as the North Atlantic Drift The water from the tropics cools as it travels north and at the same time evaporates, making the remaining water denser because of the greater concentration of salt When the cooler, saltier water sinks in the North Atlantic, it sets up a circular current within the ocean that draws more warm water behind it This system of currents makes western Europe warmer and rainier than any other comparable area of the world Over time there can be considerable variation in this system, with a corresponding variation in the climate of western Europe One such time is known as the Medieval Warm Period, which lasted from the ninth to the 14th centuries At this time harvests and the range of crops grown in northern Europe increased (which also was helped by improvements in technology) Wine grapes, for example, were grown as far north as southern England The retreat of field ice from the northern seas allowed the Scandinavian Vikings to send out colonizing expeditions to Greenland, Iceland, and, in the late 10th century, North America The Medieval Warm Period proved a temporary variation and was followed by the Little Ice Age, a period of cooling that brought longer, more severe winters and shorter growing seasons As the continent cooled, regions of the far north again became uninhabitable The last Viking colonies in Greenland died out in the 15th century, though the people of Iceland survived as a distinct society Nevertheless, the increasingly favorable climate that resulted in greater agricultural produc- tion throughout the later medieval period undoubtedly promoted economic recovery from the devastation of the Viking incursions and the disruption that followed In addition, it no doubt contributed to the spirit of self-confidence and innovation that would carry western European culture across the world after the end of the Middle Ages The Islamic World by Bradley A Skeen Islam came into being in the deep desert of Arabia and quickly spread from one end of the Old World (Eastern Hemisphere) to the other, from the straits of Gibraltar between Africa and Europe on the Atlantic to Indonesia and the Philippines in the Pacific Ocean, and from the deserts of central Africa to those of central Asia Thus, the Islamic world comprised every kind of climate from desert to rain forest Arabia Arabia was the cradle of Islam Islam arose in the year 610 when Muhammad ibn Abdallah (ca 570–632) was said to have received revelations from God in the city of Mecca in western Arabia Proclaiming himself God’s messenger and prophet, Muhammad gained followers and also decriers, eventually migrating to Yathrib (modern-day Medina) to escape persecution By the time of his death the Islamic religion had spread to the entire peninsula The Arabian Peninsula is a large body of land between Africa and Asia, though it is technically part of the latter continent It sits on a separate tectonic plate that is pulling away from Africa, making the deep rift valley of the Red Sea As a result, there is a ridge of mountains along the western edge of the peninsula The highest peak, at 12,028 feet, is Jabal alNabi Shoaib in the extreme southeastern corner (present-day Yemen) The eastern edge of the Arabian plate is being subducted under (falling below) the Eurasian plate and closing the Persian Gulf To the south lies the Arabian Sea, an arm of the Indian Ocean The climate of the entire peninsula is dry, and the Rub al-Kahli (Empty Quarter) in the southern part of Arabia is one of the driest deserts on earth, with dune seas up to 1,083 feet deep Some areas receive no measurable rainfall and have temperatures as high as 130 degrees Fahrenheit The process of desertification increased during the Middle Ages, making the ancient caravan route across the Rub al-Kahli impossible to traverse The Nedj, or central plateau, however, had considerable areas of pasturage, and the local tribes of Arabia lived by herding horses and camels through a cycle of nomadic migration between oases and other fertile areas Once the tribes were unified and no longer spent their military efforts