Little remains of the city of Mycenae now, but it was the centre of the first great Greek civilisation, which thrived between 1600 and 1100 BC. After this time, many cities were abandoned, trade ceased and their writing system disappeared. Other nearby civilisations, including the Hittites and the New Kingdom of Egypt, also declined around the same time, a phenomenon known as the Late Bronze Age collapse.
Studies of climatic indicators such as stalagtites and sea sediments suggest the Mediterranean cooled at this time, resulting in lower rainfall over the next four centuries. Some researchers think falling food production led to a decline in population and thus to the decline of civilisations in the region.
This statue represents the god Chac-Mool in the Mayan city of Chichen Itza, in what is now Mexico. Chichen Itza thrived until the 13th century, and there were still Maya living there when the Spanish arrived in the 16th. However, the heyday of the civilisation was between 200 and 800 AD, when the construction of great monuments reached its apogee. After 900 AD, many cities were abandoned.
Climate records show this decline coincided with a century of lower rainfall that would have dried out open water sources and severely affected food production.
The Romans built many aquaducts like this one in southern France near modern-day Nîmes. At its height, the Roman Empire controlled almost all of Europe, western Asia and north Africa. But by around 400 AD it had splintered into the western Roman empire, initially centred on Rome, and the eastern empire based in Constantinople – now Istanbul, Turkey.
Rome was sacked by the Visigoths in 410 AD, the first time the city had fallen in 800 years. By the end of the century the western empire had collapsed. Civil war and institutional corruption contributed to its decline.
There have long been suggestions that the climate also played a role, and new evidence emerged last year. Records oftemperatures and rainfall in western Europe over the past 2500 yearsrevealed that between 250 and 550 AD the climate flipped from dry and cool to warm and wet from one decade to the next. Such unpredictable changes are devastating for farmers, and the resulting shortages of food may have contributed to the empire's collapse.
This oil painting by Flemish artist Pieter Snayers shows an attack on a supply column during the Thirty Years war, which was fought from 1618 to 1648. It was one of the longest and most destructive periods of war in Europe's history. During the 17th century there were many other wars, revolts and conflicts. This period of instability is known as the General Crisis.
The General Crisis is usually attributed to social and economic factors, but some researchers think the real cause was a change in climate. A cooling of the northern hemisphere led to falling production and rising food prices at the time, causing famine, mass movements and, perhaps, a century of disruption.
In the 6th century, many people may have been sacrificed to the Moche god Ai Apaec – the Decapitator – depicted here in a wall painting in the Temple of the Moon in what is now northern Peru. But their sacrifices were in vain.
Between 300 and 500 AD, the Moche thrived and built cities along the coast of Peru. But their farmers depended on irrigation canals to grow their crops. By around 600 AD these channels had been buried by sand dunes. The survivors abandoned the coastal cities and moved inland.
Studies of ice cores suggest that an especially intense El Niño cycle around this time produced intense rainfall and floods, followed by a long and severe drought.