The Shape of the Modern Sea – an Excerpt from ‘Unruly Waters’

Asia’s history has been shaped by its waters. In Unruly Waters, historian Sunil Amrith reimagines Asia’s history through the stories of its rains, rivers, coasts and seas – and of the weather-watchers and engineers, mapmakers and farmers who have sought to control them.

Looking out from India, he shows how dreams and fears of water shaped visions of political independence and economic development, provoked efforts to reshape nature through dams and pumps and unleashed powerful tensions within and between nations.

Here is an excerpt from the first chapter, titled The Shape of the Modern Sea.


Looking down from orbit, the lens of a NASA satellite lands upon this patch of Earth. In the upper half of the picture lies the curve of a Himalayan mountain range, fringed by the iridescent lakes of the Tibetan plateau.

The satellite picture is a snapshot of a single moment on October 27, 2002. But there are layers of history embedded within it. It shows us the outcome of a process that unfolded in deep time. Approximately 50 million years ago, the Himalayas were created by the collision of what would become the Indian peninsula, which had detached from Madagascar, with the Eurasian landmass. The island buckled under the edge of Eurasia, pushed up the Tibetan Plateau, and eradicated a body of water later named the Tethys Sea. “Geology, looking further than religion,” E. M. Forster wrote in A Passage to India, “knows of a time when neither the river [Ganges] nor the Himalayas that nourish it existed, and an ocean flowed over the holy places of Hindustan.”

Volcanic activity under the Indian Ocean kept the pressure up, forcing layers of rock to crumple under the Indian margin to create the largest mountain chain on Earth.

So massive are the mountains, so heavy is their concentration of snow, ice, heat, and melting water that they shape Earth’s climate. Asia’s great rivers are a product of this geological history. They flow south and southeast, and they have shaped the landscape that is visible here: the force of the rivers descending from the mountains eroded rock, creating the gorges and valleys. Over centuries the rivers have carried silt and sediment from the mountains; they have deposited them along Asia’s valleys and floodplains to sustain large human populations. Writing in the 1950s, guided by maps and not yet by satellite photographs, geographer Norton Ginsburg described Asia’s “mountain core” as the “hub of a colossal wheel, the spokes of which are formed by some of the greatest rivers in the world.”

And then your eye comes to rest on what was invisible to the satellite but is now superimposed—evidence of a more recent history lies in the borders that dissect the rivers, their shapes governed by bureaucratic, not environmental, logic. Within the frame of this image alone, the mountains run through southwestern China, Nepal, Bhutan, and northeastern India. The rivers are more unruly; they spill beyond the frame of the photograph. From mountain peaks flow ten great rivers that serve a fifth of humanity—the Tarim, the Amu Darya, the Indus, the Irrawaddy, the Salween, the Mekong, the Yangzi, the Yellow River, and, at the heart of this photograph, the Ganges and the Brahmaputra. The Himalayan rivers run through sixteen countries, nourished by countless tributaries. They traverse the regions we carve up as South, Southeast, East, and Central Asia; they empty out into the Bay of Bengal, the Arabian Sea, the South and East China Seas, and the Aral Sea.

Look at the left of the picture and you can see a more compressed history. The haze of pollution that hangs over North India is a composite “brown cloud” of human-produced sulfates, nitrates, black carbon, and organic carbon. Aerosol concentrations over the Indian subcontinent are the highest in the world, especially in the winter months when there is little rain to wash the skies clean. Individual particles remain in the atmosphere only for a matter of weeks, but cumulatively the cloud lasts for months—what we see here is a fleeting archive of every domestic stove, every truck and auto-rickshaw exhaust pipe, every factory smokestack and crop fire that burned across the Gangetic plain after the end of the monsoon rains that year. But the location of the cloud, and its contributing sources, testify to a longer twentieth-century history of population growth, urban expansion, and uneven economic development through that belt of northwestern India. Over time, a constant succession of transient “brown clouds” may have attenuated rainfall over South Asia over the past half century, transforming the water cycle that binds the clouds, the mountains, and the rivers.

Finally, look at the snow on the mountain peaks visible from outer space. The time horizon this gestures toward is the future. The descent of water is vulnerable, now, to the ascent of carbon. As Earth’s surface warms, the Himalayan glaciers are melting; they will melt more rapidly in the decades ahead, with immediate consequences for the flow of Asia’s major rivers—and for the planet’s climate.


In an age of climate change, Unruly Waters is essential reading for anyone seeking to understand not only Asia’s past but its future.

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