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Climate and Calamity: a historical perspective

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Author: Jake Bailey

If you were stripped of all the trappings of modern society – smartphone, computer, TV and radio all out of action - how would you predict the weather for that day, week, month or year? 

First, you would probably look outside and consider the formation of the clouds and the strength and direction of the wind. These and other signs in nature, along with the experience you and your forebears had built up would lead to a reasonable forecast of the weather.  You could go further still. Drawing on past experience, you might be able to predict what kind of summer and winter to expect. Past experience and knowledge of the natural world would allow you to make assumptions and predictions around which you could plan your day and your year. So why not rely on these methods?

The problem with relying on our own experience and the collective memories of our society is that our expectations of future events are shaped by our past experience. How do you predict an event that neither you nor anyone you know has ever seen? With our vision limited to our collective experience, we stand on a cliff top looking out over a gently churning sea, blissfully unaware of the potential impact of weather systems on the other side of the globe.

No civilisation ever imagines its demise; it just happens, sometimes slowly over centuries, sometimes quickly in mere moments. For example, take the City of Lothal, a port which sprang up over 5,715 years ago as part of the Harappan civilisation. Located in what is now the north west corner of India, the city flourished for 500 years and the Harappan civilisation for two millennia. Forming one of the original cradles of civilisations, the Harappans were contemporaries of the Ancient Greeks and the Egyptians and thanks to agricultural prowess they were able to build great cities and a trading network that spanned the ancient world. But even the greatest of cities and the mightiest of empires can fall.

The tidal dock at Lothal

The people of Lothal specialized in the creation of jewellery and pottery. With its kilns, water treatment systems, town houses, flood defences and tidal dock (possibly the first in the world), Lothal was a developed city and a key part of an advanced civilisation. Its people lived secure in the knowledge that they were masters of their environment and destiny, until nature, as it tends to do, changed everything.

A flood of massive size ripped through the Indus valley in approximately 2000 BC, wiping out large sections of the town, destroying flood defences, filling in part of the dock and shifting the river course almost two kilometres away from the town. The city was decimated as were many others down the Indus river valley, but the people rebuilt it as best as they could, even having the time and resources to dig a new smaller channel from the dock to the river. Unfortunately for the people of Lothal they could never have predicted that another huge flood was to happen only 100 years later, which would destroy much of the city. From that point on there is no evidence of rebuilding; we can only assume that the people moved away. A city that had stood for five centuries was abandoned in one fifth of that time.

The destruction of Lothal was merely a precursor to the loss of the entire Harappan civilisation. Climate change and smaller monsoons led to more arid land combined with shifting routes of several key rivers. These factors, along with the people’s limited knowledge of advanced irrigation techniques, brought about a slow but sadly inevitable decline. The cities were abandoned and the people moved east towards the more fertile lands around the Ganges, returning to a subsistence lifestyle. With that, the Harappan civilisation of five million people faded into history.

Ancient remains of the city of Lothal

There are parallels that can be drawn with similar disasters that occur every day in the modern world. Countries, companies and individuals constantly have to deal with natural perils such as floods, while the spectre of climate change looms over us all.

However, a key difference exists between us and our forebears in that we are no longer limited by our line of sight, signs in nature and our collective memories. With the advance in modern computer technology we are able to create models which predict the danger and likely risk associated with almost any natural peril and the changes in our climate anywhere in the world. In this, we have an advantage over the people of Lothal. We can either embrace this technology and develop it further to get a better understanding of the storms that may be forming just over that horizon, or we can ignore it until they strike. If we want to save our cities from a Lothal-style destruction and our global civilisation from the potential ravages of climate change, we really have no choice. 

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