Irrigation is a good thing – but we must not repeat the mistakes

Dr Brent Clothier is Science Group Leader, Production Footprints & Biometrics Sustainable Production, at Plant & Food Research. He reports: 

From just 17% of our global lands, irrigation around the world now provides 40% of our food & fibre.  That’s a brilliant use of our natural capital!  It’s also enabling the New Zealand economy to boom through irrigation of our pastoral lands for dairying, and also through its use with higher value land-uses.

Great!

Or is it?

What are the implications of fiddling with nature’s hydrology without due consideration of (generally foreseeable) environmental consequences? Have we learned from past lessons? Are we destined to repeat well-known mistakes?

Beyond the water-driven demise of the ancient city of Babylon, today’s poster-child of an irrigation disaster is the Aral Sea.

The National Geographic has recently commented on this here.

The photos below show how we can ‘stuff up’. That’s the change since 2000 (left to right). But look at the blue line in these images – that was the shoreline in 1969.  That’s one natural capital stock of water consigned to the dust-bin of history.

laments

The National Geographic laments that

“… once the fourth largest lake in the world, Central Asia’s shrinking Aral Sea has reached a new low, thanks to decades-old water diversions for irrigation and a more recent drought. Satellite imagery released this week by NASA shows that the eastern basin of the freshwater body is now completely dry.”

Previously the Aral Sea

“… had long been been ringed with prosperous towns and supported a lucrative muskrat pelt industry and thriving fishery, providing 40,000 jobs and supplying the Soviet Union with a sixth of its fish catch.”

Those in themselves represent some pretty valuable ecosystem services.

But

“… in the 1960s, Soviet engineers decided to make the vast steppes bloom. They built an enormous irrigation network, including 20,000 miles of canals, 45 dams, and more than 80 reservoirs, all to irrigate sprawling fields of cotton and wheat in Kazakhstan and Uzbekistan”.

Cotton was called the ‘white gold’ of this region, for the steppes dominated the world supply of cotton bolls. Good stuff?

Yet in Kazakhstan

“… the system was leaky and inefficient, and the rivers drained to a trickle. In the decades that followed, the Aral Sea was reduced to a handful of small lakes, with a combined volume that was one-tenth the original lake’s size and that had much higher salinity, due to all the evaporation.”

And

“… as a result of the drying over the past decades, millions of fish died, coastlines receded miles from towns, and those few people who remained were plagued by dust storms that contained the toxic residue of industrial agriculture and weapons testing in the area.”

Ponder the ecosystem services delivered by two fishing boats – or four camels (below).  That’s the irreversible impact and sad trade-off of the evanescent ‘success’ with unsustainable irrigation.

pamir

As for the future

“… the recent desiccation is due to continued withdrawals from the rivers for irrigation and less rain and snow in the Pamir Mountains”.

The disaster of the Aral Sea is a timely reminder how we must not “stuff up” – anywhere in the world. There, here or anywhere.

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