According to a recent study published in the journal Nature Geoscience, an unusually high number of volcanic eruptions over the past 14 years may have helped to slow the progress of global warming. The explosions released sulfur dioxide particles into the atmosphere, reflecting more sunlight into space and accounting for lower average temperatures than predicted by many climate models. But the effect is not expected to last.
From 1998-2012, 17 eruptions that took place primarily in the tropics introduced a great deal of sulfur dioxide particles into the upper atmosphere. The resulting droplets of sulfuric acid reflected sunlight back into space, cooling the surface of the oceans. As the seas rebound from the cooling, scientists predict a steady rise in overall global temperatures.
Before the volcanic eruptions were taken into consideration, skeptics were quick to jump on the discrepancies of climate models and hold them as proof of fundamental flaws in the Intergovernmental Panel on Climate Change’s reports. A team of researchers led by Benjamin D. Santer from the Lawrence Livermore National Laboratory went back and reviewed satellite readings focusing on the lower troposphere and evaluated them against 28 climate models.
After factoring out the occasional cooling effects of El Niño Southern Oscillation, the researchers found that the models were accurate up until the beginning of the 21st century. By adding in the presence of volcanic activity and the possible contribution of solar cycles, sulfur dioxide emissions from coal burning plants in China, and heat absorption by the oceans, the scientists were able to account for the mysterious differences in the latter part of their predictions.
While the volcanic activity may have granted the planet a short grace period while it gets a handle on greenhouse gas emissions, researchers say that it is not bound to last for very long. Evidence that sulfur dioxide aerosols have the potential to cool the globe has led some geoengineers to call for the large-scale release of sulfate aerosols into the atmosphere. However, the method of transportation for the particles as well as possible harmful side-effects on ecosystems keep the methods from being widely adopted.
Images via the United States Geological Survey