Volcanoes, the cause of global warming? Au contraire, they’re an antidote! Via ScienceDaily:
Volcanic eruptions in the early part of the 21st century have cooled the planet, according to a study led by Lawrence Livermore National Laboratory. This cooling partly offset the warming produced by greenhouse gases.
Despite continuing increases in atmospheric levels of greenhouse gases, and in the total heat content of the ocean, global-mean temperatures at the surface of the planet and in the troposphere (the lowest portion of Earth’s atmosphere) have shown relatively little warming since 1998. This so-called ‘slow-down’ or ‘hiatus’ has received considerable scientific, political and popular attention. The volcanic contribution to the ‘slow-down’ is the subject of a new paper appearing in the Feb. 23 edition of the journal Nature Geoscience.
Volcanic eruptions inject sulfur dioxide gas into the atmosphere. If the eruptions are large enough to add sulfur dioxide to the stratosphere (the atmospheric layer above the troposphere), the gas forms tiny droplets of sulfuric acid, also known as “volcanic aerosols.” These droplets reflect some portion of the incoming sunlight back into space, cooling Earth’s surface and the lower atmosphere.