The planet’s overall temperature has been climbing upward, but that trend stalled during the early 2000s — and now scientists think they can explain why. Several studies suggest that tiny sulfur-rich particles called aerosols, which shield the Earth from the sun’s incoming rays, are to blame.
Some of those particles come from volcanic eruptions, such as the Soufrière Hills volcano in Montserrat that has been puttering along since 1995. Although such eruptions aren’t as dramatic as the 1991 eruption of Mount Pinatubo in the Philippines, which cooled the whole planet for several years, the aerosols from several small volcanoes are enough to add up to a cooling influence (SN: 8/13/11, p. 5). Also playing a role are coal-burning power plants, particularly in Asia. Sulfur particles coming