A Year Without Summer

Misty coastal conditions evoke the cooler climate period following the 1815 Mount Tambora eruption. Credit: Kevin Green

This feature article originally appeared in AFLOAT Magazine and is the latest edition of Weather with Malcolm Riley, exploring marine weather, climate history and seafaring conditions.

One of my pastimes is researching people who travelled on the original Lady Nelson (1799-1825). I was researching one female convict who departed from England on a ship called Lord Melville in July 1816. The ship arrived in Sydney in February 1817. There was nothing remarkable about her story. However, what I did find interesting was that there was an average of around four convict ships that arrived in Australia per year during the period 1800-1815. From 1816 and for the next five years an average of 17 convict ships arrived in Sydney.

To set the scene for the years post 1815. Great Britain was struggling from having financed the wars against Napoleon from 1803, culminating in Napoleon’s defeat at Waterloo in 1815. With Napoleon safely exiled on St Helena by October 1815, many soldiers and sailors were paid off with no jobs to go to. During the period of the wars the national debt soared to over £800 million (now about 64 billion): Britain’s population was about 16 million at the time. Inflation reached up to 29% in the early 1800s and was often high – up to 15% – in the following years. Things were very bad economically in Britain.

Cooler climate

From about 1812, the annual harvests in Europe had been declining. It was a period of low solar activity during which global temperatures cooled slightly. There were also regular volcanic eruptions in various locations globally in the period 1810 to 1815, these further cooled global temperatures; these volcanoes were relatively small. Volcanoes are measured by the Volcanic Explosive Index (VEI) which is an increasing logarithmic scale from 1 to 8. In this scale a VEI 2 is 10 times the scale of a VEI 1, with each increment being ten times the scale of the previous. This is the same as the Richter scale of earthquakes; a 2 is ten times the scale of a 1, and so on. The last scale eight volcanic eruption was about 25,000 years ago and this eruption formed Lake Taupo. This is New Zealand’s largest lake, 616 square kilometres.

The Tambora eruption

In 1815 Mount Tambora in Indonesia went through a series of eruptions beginning in April. These smaller eruptions culminated in the largest volcanic eruption in human recorded history. Tambora was a VEI 7. It was thought to have ejected between 100 and 150 cubic kilometres of debris into the atmosphere. This volcanic explosion was about 10 times the size of Krakatoa in 1883 (VEI 6). Immediate impacts of the Tambora eruption were the death of pretty much all life (human and animal) in the immediate surrounding area. A tsunami was generated that would have caused more human deaths away from the mountain. The resulting ash cloud blanketed all crops and vegetation, causing a famine and more deaths in the adjacent areas. The combined local human death toll was thought to be around 70,000. Prior to the eruption Mount Tambora was about 4,300 metres high and when it was finished around 1,500 metres of the mountain had gone. Not only that, the caldera that formed during the eruption was about six kilometres across and over a kilometre deep.

The ash went high into the atmosphere and travelled around the world cooling the planet even further. In some parts of the globe temperatures were estimated at 3-4˚C cooler than normal. Overall global cooling from this event was estimated to be 0.53˚C. This cooling lasted at least a couple of years.

Year without summer

In Northern Europe, the year 1816 came to be known as the year without a summer. Crops failed in a major way worldwide and especially in Europe. Across Europe this led to food shortages which led to food riots and many thousand died from hunger. As food shortages and inflation took hold there was a corresponding increase in crime, often out of desperation. In Britain, this increase in crime led to more criminal executions and transportations. In the early 1800s in Britain being sent to jail was not a punishment, you were simply held there until you were either freed, sentenced to whipping, stocks/pillory, transportation, being executed or some other punishment.

Elsewhere in the world the climate conditions led to Typhus outbreaks in China and Europe and these outbreaks killed tens of thousands of people. However, one of the most devastating results occurred (beginning) in India. The Indian monsoons were slowed for several years, and drought ensued in parts of India, especially Bengal. These conditions led to a mutation of the already present strain of cholera. There was very little resistance to this new strain and the disease spread globally with an estimated death toll in the tens of millions.

Impact on Australia

Not many records exist for climate in early colonial Australia. However, 1816 and 1817 were considered wetter and cooler in both NSW and Tasmania, the only settlements at the time. Lachlan Macquarie (Governor of NSW) wrote in his diary:

Friday 31. May !!!
It having rained incessantly and very heavily for these last four days including the present Day, there is reason to apprehend that we shall have a flood, and that there will be a serious inundation of the Rivers Hawkesbury and Nepean and South Creek; the Wind now blowing from the South East, which is the one that has generally blown during former Floods in this Colony. — It is now 5, O’clock in the afternoon and it is raining and blowing most furiously and it has been a Continued Gale of Wind from the Southeast for the last three days.

There was devastating flood in the Hawkesbury region two days after Macquarie wrote in his diary. In fact, the disembarking of the convicts from the Lord Melville was delayed by three days due to incessant rain in February 1817.

This volcano also had an effect on the arts. Lord Byron wrote the poem called Darkness during these cold times: a poem about a day when the sun did not rise. Mary Godwin was holidaying in Byron’s Villa in Switzerland during June with some other literary types. Due to not being able to get outside due to the incessant rain, to pass the time Byron suggested they all write a scary story. Godwin wrote the “Modern Prometheus”. She married later that year and became Mary Shelley and released a reworked version of her scary story as a novel called Frankenstein. Another guest, John Polidori, wrote a story about a vampire and later published the first vampire novel. If it were not for Tombara we may not have these stories in our culture.

This was also a period that had spectacular sunrises and sunsets due to the ash and debris suspended in the atmosphere. These colourful sunsets and sunrises continued for years. Some sunsets in Europe were described as being green. Joseph Turner painted many sunsets paintings after 1816; he was probably inspired by the fantastic sunsets caused by Tambora that continued for many years.

The most recent volcano in the Australian (broadly) area was the Hunga Tonga–Hunga Haʻapai in Tonga. This was thought to have been a VEI 5 and the debris from this volcano was thought to have cooled the Southern Hemisphere by about 0.1C. The predictions of when the next >VEI 6 eruption may affect the climate is unknown but expect one in the upcoming future decades.

The Smithsonian Institute has a website that shows all active volcanoes. https://volcano.si.edu/gvp_currenteruptions.cfm

Most are familiar with the Yucatán asteroid that brought about the end of the dinosaurs around 66 million years ago. However, there have been several “mass extinctions” and one was so large it is called “the great dying”. The majority of plants, insects and animal life was wiped out in this event. This extinction was caused by volcanoes in the now Siberian area, then part of the supercontinent Pangea. These volcanoes erupted for between one and two million years. They left behind many millions of square kilometres of lava fields.

New research shows volcanoes can become active even after being dormant for up to 700,000 years. Mount Gambier and Mount Schank and other dormant volcanoes in SA and VIC only became dormant (not extinct) 5,000 years ago (a blink of the eye in geological terms). Some volcanologists think they could erupt again but do not know when.

This feature article originally appeared in AFLOAT Magazine. To explore more stories like this, browse the AFLOAT Magazine archive or view the latest edition of AFLOAT Magazine.