![]() ![]() ![]() This further increases their cooling effect by allowing them to better reflect sunlight. ![]() In addition to enhancing the global cooling effect of the aerosols, the increase in aerosol spread reduces the rate at which the sulfate particles bump into each other and grow. The change in Brewer-Dobson circulation is associated with climate change. This increase in aerosol spread is mainly due to a predicted acceleration of the Brewer-Dobson circulation, which moves air in the troposphere upward into the stratosphere and then toward the poles. This change in elevation will result in the aerosols spreading faster around the world. Volcanic plumes will rise around 1.5 kilometers higher in the stratosphere in a warmer climate.įor large eruptions, models indicated that volcanic plumes will rise around 1.5 kilometers higher in the stratosphere in a warmer climate. Aerosols from moderate volcanic eruptions will therefore be more likely to remain in the troposphere and be removed by rain, reducing their potency. This discrepancy has less to do with volcanic emissions and more to do with the atmosphere: The height of the stratosphere is predicted to increase with climate change. But the cooling effect of such eruptions was reduced by around 75%. They found that for moderate-magnitude eruptions, the height at which sulfate aerosols settle in the atmosphere remained the same in a warmer climate. In their models, all the eruptions occurred at Mount Pinatubo. Modeling Mount PinatuboĪubry and his colleagues used models of both climate and volcanic plumes to simulate what happens to aerosols emitted by a volcanic eruption in the present climate and how that could change by the end of the century with continued global warming. Climate change could affect this buoyancy: As the atmosphere warms, it becomes less dense, increasing the elevation at which aerosols reach neutral buoyancy. The buoyancy of the gases also contributes to the elevation at which they settle in the atmosphere. The power of a volcanic eruption influences the elevation at which gases enter the atmosphere, with stronger eruptions injecting more aerosols into the stratosphere. The climatic effect will only last for a few weeks.” If they are injected at lower altitudes, they are essentially going to be washed out by precipitation in the troposphere. “If are injected at these altitudes, they can stay in the atmosphere for a couple of years. ![]() “What really matters is whether these are injected into the stratosphere-that is, above 16 kilometers in the tropics under current climate conditions and closer to 10 kilometers at high latitudes,” explained Thomas Aubry, a geophysicist at the University of Cambridge in the United Kingdom and lead author of the new study. Get the most fascinating science news stories of the week in your inbox every Friday. The study also found, however, that the cooling effects of smaller, more frequent eruptions could be reduced dramatically. Now new research published in Nature Communications has found that climate change could increase the cooling effect of large eruptions like these, which typically occur a couple of times every century. “What really matters is whether these are injected into the stratosphere.” This scattering warms the stratosphere but cools the troposphere (the lowest layer of Earth’s atmosphere) and Earth’s surface. Sulfate aerosols from these plumes scatter sunlight, reflecting some of it back into space. Large volcanic eruptions like Tambora and Pinatubo send plumes of ash and gas high into the atmosphere. In 1991, the eruption of Mount Pinatubo in the Philippines cooled the climate for around 3 years. Volcanic ash and gases from the 1815 eruption of Mount Tambora, Indonesia, for example, contributed to 1816 being the “year without a summer,” with crop failures and famines across the Northern Hemisphere. Volcanic eruptions can have a massive effect on Earth’s climate. ![]()
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