Inactive Volcanoes Leak Large Amounts of Sulfur Aerosol into the Atmosphere, Leading to Global Cooling

When they erupt, volcanoes draw a lot of attention. However, brand-new research conducted under the direction of the University of Washington demonstrates that even during their quiet periods, volcanoes release a surprising amount of gasses that alter the atmosphere and climate. According to an ice core from Greenland, volcanoes secretly release at least three times the amount of sulfur that is predicted by current climate models into the Arctic atmosphere.

The University of Washington led the study, which was published in Geophysical Research Letters on January 2 and has implications for gaining a deeper comprehension of Earth's atmosphere and its connection to climate and air quality.

Ursula Jongebloed, the foremost author and a doctoral student in atmospheric sciences from the University of Washington, remarked, that they discovered that on lengthier timescales the amount of sulfate aerosols emitted during inactive degassing is much higher than during outbursts. On decadal timescales, passive degassing releases at least 10 times more sulfur into the atmosphere than eruptions, and it may release 30 times more.

Sulfate Aerosols in Atmosphere

Between the years 1200 and 1850, the international team calculated levels of sulfate aerosols by analyzing layers of an ice core from central Greenland. The authors wanted to investigate the sulfur released by marine phytoplankton, previously thought to have been the primary source of atmospheric sulfate in pre-industrial times. Senior writer Becky Alexander, an atmospheric sciences professor from the University of Washington, noted that they don't know what the raw, mint atmosphere looks like in spans of aerosols. Understanding that is the first step toward achieving a deeper awareness of how humans have influenced the environment.

As per Phys, the team focused on the pre-industrial era, when it was easier to distinguish between marine and volcanic sources, and deliberately avoided any significant volcanic eruptions. To study marine phytoplankton, scientists have to calculate the quantity of sulfate disgorged by volcanoes, deduct it, and then do so. They selected to pause and address that, though, after they initially calculated the amount from volcanoes.

The Greenland Ice Sheet's central ice core records emissions from sources across a large area of North America, Europe, and the nearby oceans. The authors anticipate that this result would hold elsewhere even though it only applies to geologic sources in that region, such as Icelandic volcanoes. Following Jongebloed's findings, volcanoes are twofold as influential as marine phytoplankton, even in the dearth of large eruptions.

These sulfurous plumes in Laugavegur, Iceland, are not recorded by satellite observations. Ice core analysis shows that such plumes have a much larger effect on the level of aerosols in the atmosphere than previously believed.

(Photo : University of Washington | Seattle, WA)
These sulfurous plumes in Laugavegur, Iceland, are not recorded by satellite observations. Ice core analysis shows that such plumes have a much larger effect on the level of aerosols in the atmosphere than previously believed.

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Inactive Volcanoes' Inner Outburst

For efforts to model past, present, and future climate, the discovery that non-erupting volcanoes leak sulfur at up to three times the rate previously thought is crucial. Some solar energy is blocked by aerosol particles, whether they come from factories, tailpipes from cars, or volcanoes. If the natural levels of aerosols are higher, this indicates that human emissions have had less of an impact on temperature than previously thought, peaking with acid rain in the 1970s and decreasing with the Clean Air Act and increasingly stringent air quality standards.

Jongebloed emphasized that the sulfate aerosols have a "diminishing returns" result in which the effect of additional sulfates declines with expanding quantity. The effect that human-made aerosols have on the climate decreases by as much as a factor of two when they increase volcanic emissions, which extend the baseline concentration of sulfate aerosols. As a result, warming in the Arctic over the past few decades is demonstrating the full effects of rising levels of heat-trapping greenhouse gasses, which are the primary control over Earth's average temperature.

Jongebloed declared that the result has neither positive nor negative impacts on the climate. But better assessments of aerosols are helpful if humans want to understand how much the climate will warm in the future. Global climate models could aid in enhanced aerosol estimates. Alexander said, referring to the gas that smells like rotten eggs, The team thinks that hydrogen sulfide is the origin of the missing emissions from volcanoes. They also consider that paying close attention to the emissions of hydrogen sulfide is the finest strategy for improving these assessments of volcanic emissions.