200th anniversary of Tambora's 1815 eruption: 1815 Tambora eruption impact on the global climate

Tambora, a stratovolcano located on Sumbawa, Lesser Sunda Islands (Indonesia) reached the climax of its eruption at 7pm on 10^th April 1815 causing catastrophic impacts both locally and globally. This eruption was the largest ultra-Plinian eruption for 10,000 years and measured 7 on the Volcano Explosivity Index (VEI) releasing over 100 km3 of magma and an ash plume reaching heights of over 40 km into the atmosphere. The eruption is responsible for the largest death toll by a volcano due to both local and global impacts. 

Tambora’s eruption caused widespread global impacts in the northern hemisphere due to the release of volcanic aerosols including ash and volatiles in the atmosphere which altered the climate. This change in climate which included a drop in global temperatures was catastrophic and its effects were felt across numerous continents. 

The science behind the event:

Due to the intensity of Tambora’s eruption volcanic aerosol including ash and volcanic volatiles (sulphur dioxide, chlorine, carbon dioxide, water vapour etc.) were emitted into the stratosphere and distributed globally within months. Coarser ash particles fell (rained) out of the troposphere within weeks or months causing acid rain but finer particles and volcanic volatiles remained in the stratosphere for months or even years encircling the globe and disrupting the atmospheric dynamics which led to the climatic changes observed.

The large quantities of sulphur dioxide emitted into the stratosphere during Tambora’s explosive eruption were converted (oxidized) into sulphuric acid aerosol within the atmosphere. Various studies have estimated the quantity of sulphur dioxide emitted using multiple methods. Values vary from 60 Tg to over 100 Tg of sulphur dioxide. In comparison Pinatubo emitted an estimated 17 to 30 Tg during the eruption in 1991 and Laki emitted 122 Tg in 1783. 100 to 120 Tg of sulphuric acid aerosols have also been estimated due to the eruption of Tambora.

These sulphuric acid aerosols formed a veil and circled the globe causing a reduction of solar radiation reaching the earth’s surface due to reflection back into space and absorption which therefore lead to global cooling in 1815 along with the extreme weather. Details of these impacts are discussed in the section below.

The image below demonstrates the interaction of volcanic ash and volatiles emitted and their interaction within the atmosphere.

Source: Self S. (2006) The effects and consequences of very large explosive volcanic eruptions (Figure 6) Philosophical Transaction of The Royal Society America, 364, 2037-2097.

Effects of the disaster:

Devastation was caused by the eruption; pyroclastic flows travelled an estimated 20 km from the summit, ash fell around 1300 km from the volcano causing homes to collapse due to the weight of ash and tsunamis measuring 1m to 4m were generated 1200 km away travelling at an estimated speed of 70m/sec. Floating pumice measuring over 20cm travelled great distances from the volcano and there were reports of some found in Calcutta. The eruption was also heard 2600 km away. Within 600 km of Tambora, darkness dominated for 3 days. A 6km wide caldera was left behind by the eruption and changed the volcano’s elevation from 4300m to 2850m.

What made this eruption so devastating were the impacts felt globally due to the changes in climate and weather. 1816 became famously known as ‘the year without summer’ due to the extreme climate and weather felt globally. Temperatures fell 1 to 2.5 degree Celsius in New England and the British Isles and 0.4 to 0.7 degrees Celsius globally.

Summer in 1816 was cooler and wetter and significantly different than previous years. In North America in 1816 dry fog dimmed sunlight to such an extent that sun spots were visible to the naked eye. Greenland and Indonesia experienced acid rain and in Europe and North America daily temperatures were low. Frost and snow fell in New England and Canada in June.  According to reports 30cm of snow covered Montreal in Canada. Heavy rain up to 80% more than normal fell in Western Europe and China causing floods and destroying crops. In contrast, Russia experienced warm and dry summers for three years after the eruption. Winter however was also warmer than expected in these countries. The Indian monsoon was disrupted causing devastation for harvests and freezing temperatures were felt in Madras in India. Livestock were killed in New England due to the cold temperature.

These impacts were felt 3 months following the eruption due to the volcanic aerosols travelling globally by than. Extreme climate and weather caused shortened growing seasons leading to main crops failures in northern hemisphere. Acid rain and prolonged precipitation in Europe also destroyed crops. Poor harvest lead to shortage of crops causing widespread famine which in turn lead to diseases and social distress. Riots were also reported in Europe as a consequence.

The human toll of the eruption was devastating. Tambora was responsible for the largest death toll ever caused by a volcano eruption. An estimated 12,000 people died directly from the impact of the eruption and an estimate total of 71,000 people died from both primary and secondary causes. Some estimates even suggest that 91,000 people in total perished due to Tambora. The villages of Tambora on the volcano were entirely wiped out and out of the 12,000 Sumbawan population, only 26 survived the eruption.

Starvation and famine lead to some farmers abandoning their land and migrating elsewhere. Some people in Europe also migrated in search for food. The economic impacts were also devastating with failure of crops. Of the few crops that survived, prices were increased greatly. Some of the effects of the eruption on the weather and climate lasted a few years following on from the eruption; however 1816 was the most devastating.

Response to disaster:

The eruption took place in 1815 when technology and knowledge on volcanoes was very limited or did not exist at all. The news of the eruption would have taken months to reach other continents since the only method of dissemination was by ships and no connections were made between the eruption and extreme climate that occurred during the following year. The sound of the eruption was even thought by soldiers to be sounds of canons being fired and therefore they went looking for a battle. Due to these limitations the response to the eruption and global impacts were virtually non existence and being the biggest eruption in 10,000 years it is also justified that the human civilisation did not know the consequence of such eruptions both locally and globally.

According to research and reports the volcano showed signs of activity a year before the 1815 eruption, however due to the lack of understanding it is unlikely that the population living in the vicinity knew what was coming therefore during the eruption most of the population living in the vicinity perished and the villages of Tambora were also wiped out as mentioned above. Reports suggest that it took the island of Sumbawa a century to recover.

In 1816 when the global impacts of extreme climate were felt leading to crop failures and flooding in some countries such as China and Europe, the price of crops were increased greatly from 1815 to 1817 in response to the shortage and parts of the population had to migrate in search for food due to this. Farmers had to abandon their lands as mentioned which was disastrous for the economy and riots in some parts of the world took place due to social stress created by the shortage of food and starvation and disease. There was not much that could have been done to salvage lands and crops since the extreme weather were prolonged. Flooded land were also abandoned. Although research does not exist currently showing details of responses, it is likely that they were limited and not much could have been done.

Sophisticated advances in knowledge and technology including climate models were only developed decades later and even being currently developed. Research is still being carried out to understand the climatic impacts of Tambora and the potential impacts of another eruption of that size occurring today.

As previously mentioned, Tambora was active for a year before the climax eruption took place and due to the lack of knowledge and technology the population ignored the signs. If today’s knowledge and technology existed back in 1815 it would have saved numerous lives; the population within the vicinity could have been evacuated saving thousands. It is unlikely that the climatic effects of the eruption could have been prevented therefore the impacts that were felt globally would still have been devastating. If methods of rapid communication were not limited during 1815, other continents would have known about the eruption and possibly linked the eruption to the climatic effect.

Following the eruption of Tambora, no link was made between the eruption and changes to the climate and it was not until the eruption of Krakatoa in 1883 when it was made. Research since than has been carried out to increase our knowledge and understanding of this phenomenon. When eruption of Pinatubo in 1991 occurred, scientists gained a deeper understanding of the consequences of eruptions and climate alteration. The eruption of Pinatubo also lead to a drop in global temperature for up to 3 years and because of the research linking Tambora’s eruption to climatic anomaly scientists were able to further advance their understanding this time round.

Sophisticated climate models which include numerical computer models have and are being developed by scientist today to advance our understanding of eruptions and their impact on climate. These help not only understand Tambora’s eruption but also potential future eruptions of a similar nature and size.

If an eruption of the same size as Tambora was to erupt today, the impacts would also be catastrophic. Although knowledge and technology has rapidly developed and scientists can to a certain extent predict volcanic eruptions by monitoring them, volcanoes are unpredictable and each volcano behaves differently and even varies each time it erupts. The world’s population has also rapidly increased since the 1815 eruption, resources are overstretched and thousands of people around the world put themselves at immense risk by living in the vicinity of volcanoes which are capable of a VEI 7 or even greater eruption. It appears that the human population has not learnt from past events such as Tambora.

We cannot even comprehend the utter devastation that climatic alterations as a consequence of an eruption today would cause. The eruption of Tambora and its impacts on the global climate has shown us what volcanoes are capable of and this study has given an insight on this.

If you follow the link below, it will show you the full animated movie of the above image by the Asia-Specific Data Research Center of the global temperature changes following the eruption: http://apdrc.soest.hawaii.edu/projects/SOS_MP/past_climate_2.php

  

References:

• Singurdsson H., Houghton B., McNutt S.R., Rymer H., Stix J., (2000), Encyclopaedia of Volcanoes, United States of America, Academic Press.

• Smithsonian Institution, Global Volcanism Program (2014) Tambora, Retrieved (July 23, 2014) from http://www.volcano.si.edu/volcano.cfm?vn=264040

• Self S., Gertisser R., Thordarson T., Rampino M.R., and Wolff J.A. (2004).  Magma volume, volatile emissions, and stratospheric aerosols from the 1815 eruption of Tambora. Geophysical Research Letters, Volume 3, L20608, 1-4.

• Sothers R.B., (1984), The great Tambora eruption in 1815 and its aftermath, Science, 224 (4654), 1191-1198.

• Auchmann R., Bronnimann S., Breda L., Buhler M., Spadin R., and Stickler A. (2012), Extreme climate, not extreme weather: the summer of 1816 in Geneva, Switzerland, Climate Past, 8, 325-335.

• Smith J. (2007) Climatic effects of the 1815 eruption of Tambora, Geology, 470, 26-32.

• Self S. (2006) The effects and consequences of very large explosive volcanic eruptions, Philosophical Transaction of The Royal Society America, 364, 2037-2097.

• Arfeuille F. (2012), Impacts of large volcanic eruptions on the stratosphere and climate, Doctorate Dissertation submitted to ETH Zurich.