Developed from the study of tree rings more complete atlas of the severe drought that hit Asia in the last 1000 years.Water is the source of life and of food. Monsoon rains in Asia, for example, provide food to nearly half the world population. If these rains are lacking, therefore, hunger threatens entire villages. History has given us many examples of this. And now a team of researchers from the Lamont-Doherty Earth Observatory of Columbia University have developed the most comprehensive atlas of the severe droughts that have hit Asia in the last thousand years.
From the study of tree rings, researchers led by Edward Cook, revealed in “Science” the most detailed record until at least four epic drought: from which may have helped the fall of the dynasty Ming in 1644 to another that killed tens of millions of people in the late 1870s.
In some species of trees, the rains determine the width of annual growth rings and these rings are the scientists are able to read. But it has not been easy. Researchers have traveled for 15 years across Asia locating enough old trees that could provide long-term records. This search led investigators to more than 300 locations, from Siberia to Indonesia and northern Australia, and to Pakistan in the west and Japan in the east. Therefore, as Kevin Anchukaitis explains study co-author, “provided everything from the rainforests of the lowland to the Himalayas.”
The ring records show at least four major droughts that are related to catastrophic events in history. For starters, the study suggests that climate may have played a decisive role in the fall of the Ming Dynasty in 1644. The rings provide additional evidence of a severe drought in China to some historical texts refer to as the worst in five centuries. This study is limited to a period of three years, 1638-1641. This drought was most severe in northeastern China, near Beijing, and it is believed that influenced the peasant rebellions that eventually accounted for the decline of the Ming dynasty.
A weakening of the monsoon rains between 1756 and 1768 coincided with the collapse of the kingdoms of what is now Vietnam, Myanmar and Thailand, as researchers have seen the first in the rings of teak in Thailand, and later in Vietnamese cypress. Some historians had speculated that the weather had played an important role for those politicians as abrupt changes occur simultaneously, but this drought was not even documented in historical records.
However, the worst drought that scientists have found is the “Great Drought” of the Victorian era between 1876 and 1878. Its effects were felt throughout the tropics and, by some estimates, the resulting famine killed 30 million people. According to the evidence provided by the rings, the effects were particularly severe in India, but were also extended to China and now Indonesia.
The researchers believe the study will not only help historians to understand how it has affected the environment in the past, but to help scientists trying to understand the potential of large-scale disruption of the climate in the context of global warming.