The largest volcanic eruptions of the 21st century have shown how quickly volcanic activity can become a regional or global disaster. Among the most powerful was the January 2022 Hunga Tonga-Hunga Ha'apai eruption in Tonga, which produced an enormous atmospheric plume, tsunami and pressure waves detected around the world. Other major disasters include the 2010 Mount Merapi eruption in Indonesia, the 2002 Nyiragongo eruption in the Democratic Republic of Congo and the 2019 Whakaari eruption in New Zealand. Their effects ranged from deaths and mass evacuations to destroyed homes, disrupted travel and atmospheric changes. Scientists continue to study these eruptions because their impacts extend far beyond the volcano itself.Which Eruptions Were Most Powerful?There is no simple list of the biggest volcanic eruptions because scientists measure eruptions in different ways, including explosivity, erupted material, plume height and human impact. Hunga Tonga stands out for its extraordinary atmospheric reach, while Merapi and Nyiragongo caused severe humanitarian consequences. Whakaari became one of New Zealand’s deadliest modern volcanic disasters. Together, these events demonstrate the different ways volcanic eruptions can threaten communities and affect the wider world.Hunga Tonga erupted in Tonga in January 2022.Merapi erupted in Indonesia in 2010.Nyiragongo erupted near Goma in the Democratic Republic of Congo in 2002.Whakaari erupted off New Zealand’s North Island in 2019.Mount Ontake erupted in Japan in 2014.Deadliest Eruptions Across The WorldThe 2010 Mount Merapi eruption in Java, Indonesia, was one of the most destructive volcanic events of the century. USGS records say the eruption killed 341 people, destroyed more than 2,000 homes and forced nearly 350,000 people to evacuate. Scientists said timely warnings and large-scale evacuations saved thousands of additional lives.In the Democratic Republic of Congo, the 2002 Nyiragongo eruption sent fast-moving lava into Goma, destroying homes and forcing a huge evacuation. Estimates of deaths varied, with UN and humanitarian reports placing the toll at about 147, while later scientific assessment suggested a lower figure. The disaster displaced hundreds of thousands and demonstrated the danger of volcanoes located close to densely populated cities.Hunga Tonga's Global Scientific ImpactThe Hunga Tonga eruption on January 15, 2022, in the South Pacific was exceptional. NOAA describes it as the most explosive volcanic event of the satellite era, while the 2025 international assessment classified it as a high-magnitude VEI 6 submarine explosion. Its plume reached the upper atmosphere, and the eruption generated tsunami waves, atmospheric shock waves and global pressure disturbances.The eruption also produced unusual atmospheric effects. The 2025 scientific assessment found that Hunga increased global stratospheric water vapour by about 10%, with much of that additional water still present through 2025. It also affected stratospheric ozone and produced cooling in parts of the upper atmosphere, although its effect on surface climate was small.Key HighlightsHunga Tonga erupted in Tonga in January 2022 and generated a major tsunami.The eruption sent material and water vapour deep into the atmosphere.Merapi’s 2010 eruption killed 341 people in Indonesia.Nyiragongo’s 2002 lava flows devastated parts of Goma and caused mass displacement.Whakaari’s 2019 eruption killed 22 people and injured 25.Japan’s Mount Ontake eruption in 2014 was a deadly phreatic eruption with a plume reaching about 7,000 metres.Global Lessons From Major EruptionsThe biggest volcanic eruptions of the 21st century show that danger depends not only on explosive power but also on location and population exposure. Merapi demonstrated the value of early warnings, while Nyiragongo showed the risks faced by cities near active volcanoes. Hunga Tonga revealed that a submarine eruption can create hazards across ocean basins and influence the atmosphere worldwide.Modern satellites, seismic networks, evacuation systems and international scientific cooperation have improved volcanic monitoring. However, major eruptions remain difficult to predict precisely, especially when they occur underwater or change rapidly. Continued monitoring and public preparedness remain essential for reducing future losses.Disclaimer: This article is provided only for knowledge and news-information purposes and does not replace official disaster warnings, scientific assessments or emergency guidance.
