Impact of Stratospheric Injections From Volcanoes and Geoengineering: Pinatubo vs Hunga Eruption
1:00 – 2:00 pm MDT
Georgiy Stenchikov
Dr. Stenchikov graduated with distinction from Moscow Physical-Technical Institute in 1973 and completed his Ph.D. there in 1977. As the head of a department at the USSR Academy of Sciences, he led pioneering research using computational analysis to assess humanity’s impact on Earth's climate, including the effects of nuclear war.
Beginning in 1992, he spent 17 years in the United States, working first at the University of Maryland and then at Rutgers University from 1998. In 2009, he joined King Abdullah University of Science and Technology in Saudi Arabia as a Professor and Chair of the Earth Sciences and Engineering Program, a role he held until 2021. He retired after 15 years of service, leaving a legacy of significant contributions to climate modeling, atmospheric physics, fluid dynamics, radiation transfer, and environmental sciences.
In 1986, Dr. Stenchikov was recognized for his achievements in climate impact modeling; he received a prestigious award from the Council of Ministers of the Soviet Union. He served as a contributing author to the Nobel Prize-winning IPCC AR4 report in 2007. In 2022, he was honored by the Future of Life Institute for his work in advancing and promoting the science of nuclear winter. Most recently, in 2024, the Association for Computing Machinery awarded him the Gordon Bell Prize for his breakthroughs in climate modeling.
Explosive volcanic eruptions offer crucial empirical insights into the effects of natural and anthropogenic stratospheric injections on Earth’s climate. The composition and early dispersion of injected materials, whether volcanic or man-made, play a key role in determining the long-term evolution of aerosol and gaseous plumes in the stratosphere.
Modern climate models have made significant strides in realistically simulating the behavior of volcanic clouds. This study used the WRF-Chem regional meteorology–chemistry model to analyze the plume evolution of the Pinatubo (1991) and Hunga (2022) eruptions. Our goal was to assess the sensitivity of plume dynamics to factors such as injection height, ash presence, initial volcanic material concentrations, and water vapor (WV) injections.
The 1991 Pinatubo eruption, the largest explosive event of the 20th century, injected an estimated 17 Mt of SO₂ and approximately 100 Mt of WV into the lower stratosphere. Despite this, uncertainties persist regarding the exact SO₂ mass and the altitude at which volcanic debris was released. Comparatively, the shallow-underwater Hunga eruption on January 15, 2022, emitted only 0.5 Mt of SO₂ but released 150 Mt of WV into the upper stratosphere. The resulting WV injection was largely retained in the stratosphere, increasing its water vapor content by 10%. While Hunga’s SO₂ injection was relatively minor compared to climate-altering events like Pinatubo, its substantial WV release raised concerns about possible shifts in stratospheric chemistry and dynamics, including potential near-surface warming.
Our findings underscore the pivotal role of the early evolution of volcanic clouds in shaping the climate impacts of eruptions. They highlight the necessity of accurately simulating or prescribing these processes within climate models. By comparing Pinatubo and Hunga, we identified new mechanisms and critical uncertainties that must be accounted for when optimizing strategies such as solar radiation management