Tambora: The Eruption That Changed the World provides us with just that lived experience of climate change. In 1815, Mt Tambora on the Indonesian island of Sumbawa erupted in the most destructive volcanic eruption in human history. Vulcanologists classify the blast as ‘mega-colossal’ – a score exceeded only by ‘apocalyptic’. More significant than this measure of magmatic output, however, was the impact on global climate.

A ‘great husk of matter shed, Tambora’s sleek, residual cloud – made up of pulverised mineral matter, gases and sulphate aerosol particles less than a micron in thickness – would hang at altitude for more than two years’, teleconnecting Tambora with global climate change. The Earth’s average temperature plummeted by 1.5 degrees for a decade, creating the ‘Year without Summer’.

The strength of Gillen D’Arcy Wood’s beautifully produced book lies not just in the way it seamlessly integrates complex scientific evidence into an eminently readable text, but also in the way it weaves the personal, cultural, and historical into a richly textured account of the lived experience of this volcanically induced climate change event. As a professor of English and novelist (originally Australian but long-time resident of Illinois), Wood vividly links the scientific literature in which Tambora’s legacy is largely documented with the literary and historical events which we only now know to have been caused by Tambora.

Wood’s ability to make the general personal is one of the many achievements of this book. We experience the immediate horror of Tambora and its forty thousand local victims through the eyes of the desperate raja of Sanggar. We see the stratospheric dust clouds shrouding Europe in the tumultuous skyscapes of Constable and Turner – Tambora was ‘an attractive killer. A tragedy of nations masquerading as a spectacular sunset.’ We immerse ourselves in an icy Europe through the fiction, poetry, and travel writing of Mary and Percy Shelley and Lord Byron. The poet Li Yuyang describes the unending rains and resulting famine in the Yunnan province of China with heart-wrenching despair. Irish writer William Carleton guides us through this less well-known precursor to ‘The Great Famine’ of the 1840s, while in America we accompany four barefoot schoolchildren on a desperate and heroic race though unseasonable snowdrifts to reach the safety of their home. Such individuals must stand for the silent thousands who died of famine, starvation, and disease around the world in the years that followed Tambora’s eruption.

Mount Vesuvius in Eruption, 1817 by J.M.W. Turner (Yale Centre for British Art)

Wood does us a great service in linking these often poorly documented events to their ultimate cause, but he does not stop with the immediate devastation. He follows the forensic trail of Tambora’s lethal legacy along less obvious paths. It is not surprising that the once wealthy kingdom of Sumbawa never recovered from its devastation, but the long-term consequences for the Yunnan province, and its descent into opium cash-crops, are sobering. So too the impetus of cold east-coast weather in America on westward migration and the first great depression of 1819–22. An entire epoch of tragic British Arctic exploration, in search of an elusive north-west passage, can be pinned to a momentary thaw in the northern waters caused by Tambora. Even more chilling are the far-reaching consequences of the typhus epidemic in Ireland and the outbreak of cholera in the Bay of Bengal in monsoon season. Under normal conditions, cholera feeds harmlessly on vast phytoplankton blooms which form in river mouths and drift along the east Indian coast. Wood writes:

In 1817 the aquatic environment of the Bay of Bengal had deteriorated radically owing to the disrupted monsoon, a consequence of Tambora’s dimming presence in the stratosphere. By a process that remains mysterious in its details, the altered estuarine ecology then stimulated an unprecedented event of genetic mutation in the ancient career of the cholera bacterium. From this point the cholera’s path is chillingly clear. Changes in water temperature and salinity promote the bloom of zooplankton, the cholera’s main aquatic host, while flooding dredges up deep-welling nutrients and transports the pathogen into the water system of coastal human communities. Barely above sea level, the waterways of the Bengal delta ebb and flow with the tides of the bay. If changes in rainfall patterns drive sea levels higher, bay waters ooze and swell inland, infiltrating the ponds and tanks dedicated to human use. The mix of fresh and salt water keeps the plankton blooms and their bacterial tenants at the surface. From there, the v. cholerae is but a cup of water, rice pot or shellfish meal away from colonising its first human victim. And if that first host is tended to in unsanitary conditions and his waste finds its way back to the water sources of the community, the stage is set for cholera to rise up from the waters in its ghoulish mortal shape.

Cholera, a horrifying disease that within hours ‘turned a walking, talking person into a sluice’, marched relentlessly in successive pandemic onslaughts, in the company of soldiers and travellers, across Asia and Europe into Africa and America, taking with it millions of lives.

These compelling images, of poverty, disease, starvation, mass migration, political instability, and long-lasting economic damage, are largely unexpected consequences of a volcanic eruption which, had it occurred a few years earlier (like the ‘unknown’ eruption of 1809), might well have gone entirely undocumented in our history. But Tambora’s impact on our climate eventually passed. Warmth returned, crops flourished, and communities recovered. It was, ultimately, a short-term blip in the long-term records. In this brief historical interlude, brought to life with such colour and vivacity by Wood’s prose, we see a distant reflection of what might lie in our future. A few degrees, a few centimetres, does matter – very much. Climate change, when it happens, happens to all of us, and the consequences are unpredictable and terrible.

Tambora: The Eruption That Changed the World, is an engaging and fascinating mix of science and literature. At its close, Wood invites us to imagine ‘if you can bear it … Tambora scaled to a planet of ten billion, and lasting for centuries’. I am not sure that we can, but this book, in all its beautiful and eloquent tragedy, may well be the one to help us try.