Volcanoes And Climate Change: The Case Of Tonga Volcanic Eruption

By Shreya Ramchandran

The recent volcanic eruption in Tonga left the world in shock at the magnitude of devastation that was put upon the Polynesian country. The volcanic eruption destroyed homes and streets and took the lives of people and wildlife in its wake. It has implications on climate change and global warming too, but surprisingly it is not as notorious as the negative effects of human activities on rising temperatures. 

On January 15, 2022, the world awoke to the news of a volcanic eruption in Tonga, a Polynesian country. Homes and lives were destroyed and all communication to and from the island was disrupted. Situated in the seismically active Pacific Ring of Fire, the underwater volcano Hunga-Tonga-Hunga-Ha’apai (HTHH), is about 65 kilometers from the north of Tonga’s capital Nuku’alofa. On erupting, HTHH sent out huge plumes of ash, rocks, volcanic gasses and debris about 30 kilometers into the sky, causing around a 4-foot wave of tsunami to wash on the island. Images of the aftermath show homes and streets destroyed, laden with layers of ash and air filled with smoke. The country in the coming days will most likely face food shortages as crops and fields were destroyed with the ash and huge waves of water.

The effect of this natural disaster is yet to be seen as communication with the island is returning languidly. While the death count has not been confirmed, the after-effects of this natural disaster are expected to be severe and unprecedented. The loss of life and property is seen as inevitable, as sudden relief and evacuation measures were not available. People left everything behind in search of higher ground. Further, the eruption could have negative impacts on marine life including coral reefs as well as the coastlines and the fisheries. The livestock and mammals are adversely affected due to high amounts of toxic gasses and ash which coats the area after the eruption. The increase in the acidity of water as well as change in climatic temperature and food supply, even for a few days, can affect the survival rates of marine animals.

Volcanic eruptions of such intensity, not only affect human and animal life, but are also said to have consequences on climate change and global warming. Volcanic eruptions of this nature are said to have a cooling effect on the earth’s atmosphere. By spewing out ash and sulfur dioxide to high heights, it has the ability to reflect the sun rays away from the earth, allowing the temperature to cool down, even if it is by a small amount. The sulfur dioxide condenses in the stratosphere and forms sulfate aerosols which in turn reflect the radiation of the sun back to space. The latest instance of such a cooling effect was  the volcanic eruption of Mount Pinatubo near the Philippines, in 1991. The ash cloud spewed by the volcano reached about 35 kilometers into the atmosphere and cooled parts of the world by around 0.4 degrees celsius for around two years after the eruption. 

However, the recent eruption of the HTHH volcano might not have a similar impact.  The duration of the eruption was not long enough and the amount of sulfur released was insufficient to block the sun rays. Still, the gravity of the cooling effect will only be noted after a few days of keen observation of the global average temperature.

Apart from this, volcanic eruptions also release large amounts of carbon dioxide amounting to 100-300 million tons. Sadly, when compared with the human contribution to climate change, this release of carbon dioxide is considered negligible. It amounts to  just 1% of what humans release by burning fossil fuels. From 1890 to 2010, natural causes aided in global warming  by a plus or minus 0.1 degrees celsius. On the other hand, The Intergovernmental Panel on Climate Change (IPCC) has found that in 2018, around 89% of the carbon dioxide emission came from burning fossil fuels. Of this, coal is seen as the dirtiest form of fossil fuels, accounting for 0.3 degrees celsius for every 1-degree celsius rise in global temperatures. It is estimated that human contribution to climate change adds to about 9.5 billion metric tons per year by burning fossil fuels. To this, deforestation accounts for another 1.5 billion tons of carbon dioxide into the atmosphere. Forests and oceans can only absorb so much carbon dioxide, leaving around 5 billion metric tons still in the atmosphere. This affects rainforests as the number of forest fires have increased over the years. The Amazon rainforests have experienced loss of life and plantations due to forest fires caused by deforestation activities and the heating up and drying out of the rainforests caused by rising temperatures. In the first seven months of 2020, more than 13,000sq km of the Brazilian Amazon was burned. Other human activities such as improper waste disposal also adds to our causes of climate change. About 10 to 25 percent of accumulated garbage (mainly plastic waste) from various countries finds its way to big, but poor islands where they start to become mountains. As time passes, this pile of garbage slowly accumulates methane, which on reaching a certain temperature, incinerates and causes high amounts of air pollution and increased levels of carbon dioxide in the atmosphere adding to the rising temperatures. This paints a bleak picture of the impact of human activities and puts into perspective the consequences of our actions.

The impact of the eruption of the THTT volcano is still to be felt as the world grapples for news and communication from the ones facing this terrible disaster. Given past experience, the climatic and human impact of such an event is not unknown. The consequences of this disaster are devastating and heart-breaking and will take some time to heal. However, the fact that the global warming caused by such eruptions is not as significant as the consequences of our human actions provides an eye-opening picture about our impact on the planet we live in. Given the current situation of climate change and global warming, with the atmospheric temperature at a rise of about 1.5 degrees celsius over pre-industrial times, it is up to us to change our ways of life, and ensure that we do not bring devastating consequences upon ourselves. Natural disasters are, sadly, beyond our control. However, our actions aren’t. We must strive to reverse tables, and allow natural disasters to live to their name, rather than trying to beat them and become infamous for our choices and actions. 

Shreya Ramchandran is a second-year undergraduate Economics and Finance student at Ashoka University.

Image credits – https://abcnews.go.com/International/photographic-timeline-tonga-volcano-eruption/story?id=82323579

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