Today’s news carried this interesting article about the Eyjafjallajokull volcano in Iceland. (Typing the word Eyjafjallajokull is great fun–and and trying to correctly say it even more so.)
In certain cases, volcanic eruptions spew large amounts of sulfur dioxide into the atmosphere, where it forms an aerosol, essentially a suspension of sulfate particles in a gas. These aerosols can stay high in Earth’s atmosphere, often for two to three years, and, if the eruption is large enough, will spread out over an entire hemisphere or even the globe. Aerosols absorb some of the longer wavelength terrestrial radiation from Earth, warming the upper atmosphere. They also reflect incoming sunlight back to space, leading to cooler surface temperatures. In this way, a localized volcanic eruption can affect climate worldwide–past volcanic events have led to colder seasons, freezing at lower latitudes, and crop failures. Learn more by reading this story of how scientists have used observations and models to fit the pieces of the volcano-climate puzzle together.