Global warming is still a major concern but a "warming hiatus" has actually been happening over the last 15 years. And according to a study, small volcanic eruptions played a part in keeping the planet's temperature down.
It has long been established that volcanoes have the ability to cool down the atmosphere through the sulfur dioxide they spew out during eruptions. The combination of sulfur dioxide and oxygen results into sulfuric acid droplets which persist in the Earth's upper atmosphere for months. This reflects sunlight from the planet, thus helping lower overall temperatures in both its lower atmosphere and surface.
Previous studies have already suggested that volcanic eruptions during the early 21st century might be responsible for up to a third of what's causing the warming hiatus. Now a new study published in the journal Geophysical Research Letters complements earlier research made public through the same journal, noting how a number of small volcanic eruptions substantially deflected solar radiation at levels higher than what was previously estimated.
According to Benjamin Santer, a scientist from the Lawrence Livermore National Laboratory and the lead author for the new study, the new work highlights that climate signals from volcanic eruptions in the late 20th and early 21st century are highly observable in different sets of data.
In the new study, researchers were able to show that the effects of eruptions in the late 20th and early 21st century can be identified positively in levels of reflected solar radiation from the top of the atmosphere, as well as moisture and temperature levels.
A crucial step in clearly identifying the effects of smaller volcanic eruptions was to remove "climate noise" due to La Niñas and El Niños.
Researchers noted that because signatures from the volcanic eruptions are observable after factoring in multiple climate variables, this really supports the assumption that smaller volcanic eruptions have an influence on climate despite their modest size.
"If we wish to accurately simulate recent climate change in models, we cannot neglect the ability of these smaller eruptions to reflect sunlight away from Earth," added Mark Zelinka, also a scientist from the Lawrence Livermore National Laboratory and one of the authors for the new study.
Aside from scientists from the Lawrence Livermore National Laboratory, researchers from Remote Sensing Systems, Environment Canada, NASA Langley Research Center and the Massachusetts Institute of Technology also participated in the study. Other authors include: Frank Wentz, Jean-Paul Vernier, David Ridley, Carl Mears, Gardar Johannesson, John Fyfe, Francisco Beltran, Jeffrey Painter, Celine Bonfils and Susan Solomon.
