THE incredibly complex chaos of Islamic State and the upheavals of Syria and Iraq may have a very simple cause: The region’s worst drought in 900 years.

A NASA study published in the Journal of Geophysical Research-Atmospheres shows the Middle East is in the grip of a mega-drought that began in 1998. It has taken hold in Cyprus, Israel, Jordan, Lebanon, Syria and Turkey.

The water shortage has been taking a steadily increasing toll on farmers and the region’s ecology, with crop failures, dust storms and record-breaking heat now an annual event.

But the true extent of the drought is only now becoming clear.

“The range of how extreme wet or dry periods were is quite broad, but the recent drought in the Levant region stands out as about 50 per cent drier than the driest period in the past 500 years, and 10 to 20 per cent drier than the worst drought of the past 900 years,” a NASA statement reads.

FINGERPRINTS IN THE RAIN

NASA climate scientists have been mapping a database of the Mediterranean and Middle East’s tree rings — the pattern in which a plant’s new growth is laid upon itself each season — spanning several thousand years.

Tree rings are a kind of ecological fingerprint.

Each band reveals how much water the tree has been taking in, and how optimal conditions were for growth.

When a tree goes through a period of drought, the bands get thinner. The more thin bands, the longer the drought.

Mapping when — and where — these trees were suffering water starvation offers an opportunity to understand the natural variation in the areas weather.

“If we look at recent events and we start to see anomalies that are outside this range of natural variability, then we can say with some confidence that it looks like this particular event or this series of events had some kind of human caused climate change contribution,” says lead author of the study Ben Cook.

In the case of the Middle East, a wide-reaching drought spanning more than 15 years has not been seen for more than 900 years.

Historical documents dating from 1100AD were used to corroborate the accuracy of the tree-ring map.

NO RAIN, NO ESCAPE

The flood of refugees out of the Middle East and into Europe is a natural consequence of the conditions, the study infers.

Historically, when there is drought in the Eastern Mediterranean, there is no escape to the west. Both ends tend to suffer at the same time.

Which generates cause for conflict.

“It’s not necessarily possible to rely on finding better climate conditions in one region than another, so you have the potential for large-scale disruption of food systems as well as potential conflict over water resources,” says co-author Kevin Anchukaitis.

But the patterns established over thousands of years do suggest refuge: To the north.

When eastern North Africa is dry, Greece, Italy, France and Spain tend to be wet. And vice-versa.

DEVIL IN THE DETAIL

From these patterns, the NASA scientists were able to identify the engines behind the Middle East’s weather: The North Atlantic Oscillation and the East Atlantic Pattern.

These regular wind patterns over the Atlantic are themselves driven by oceanic currents and temperatures.

Periodically they push rainstorms away from the Mediterranean, instead causing long dry winds to circulate in their place.

The NASA research shows that this time, however, the drought is different.

Its behaviour does not match the patterns clearly established over the past thousand of years.

“The Mediterranean is one of the areas that is unanimously projected as going to dry in the future [due to man-made climate change],” climate scientist Yochanan Kushnir states in the NASA release.