A new study has stated cooling from volcanic eruptions are partially to blame for a "pause" in global warming, a mismatch in the climate models and actual figures.
According to LiveScience, the most recent pause in global warming is about 15 percent off of the projected model. Sometimes referred to as hiatuses, pauses began being recognized in 1998 when the surface temperatures on Earth suddenly slowed amidst a swift rise.
The International Panel on Climate Change (IPCC) previously predicted that the warming rate from before 1998 would continue in the foreseeable future. From the 1970s to 1998, the average temperature rose by an average of 0.31 degrees Fahrenheit, which slowed to 0.072 F from 1998 to 2012.
"Part of the lack of the increase in warming for the last 15 years may be due to the cooling effect of volcanoes," study co-author Céline Bonfils, a climate scientist at Lawrence Livermore National Laboratory (LNNL) in Livermore, Calif., told LiveScience.
Reported in a study published in the journal Nature Geoscience, the researchers found that 17 small volcanic eruptions since 2000 produced enough aerosols to influence a global climate slowdown. Aerosols have a cooling effect on the Earth by scattering their fine particles in the atmosphere and absorbing the sun's energy.
Brian Toon, of CU-Boulder's Department of Atmospheric and Oceanic Sciences, previously reported similar findings in a study from a year ago.
"The biggest implication here is that scientists need to pay more attention to small and moderate volcanic eruptions when trying to understand changes in Earth's climate," Toon said in a press release. "But overall these eruptions are not going to counter the greenhouse effect. Emissions of volcanic gases go up and down, helping to cool or heat the planet, while greenhouse gas emissions from human activity just continue to go up."
In the new study, the researchers tied the eruptions since 2000 with temperature shifts in the troposphere during the same time period. According to global satellite records, there was a temperature dip in the troposphere during the climate change pause in 1998.
"The most recent [climate] simulations include all the major volcanoes up until Pinatubo in 1991; then the aerosols decay back to zero," study co-author Mark Zelinka, a LLNL climate scientist, told LiveScience. "It was only recently that it was known that these medium-sized volcanoes were putting a lot of highly reflective particles into the stratosphere."
