In a recent edition of the Geophysical Research Letters journal, researchers from the Lawrence Livermore National Laboratory show that over the last 15 years, the global warming hiatus might have been influenced by small volcanic eruptions.
It is a well-known fact that sulfur dioxide that is discharged when a volcano erupts can cool of the atmosphere. The mixture of the sulfuric dioxide with oxygen causes the formation of sulfuric acid droplets at the upper part of the atmosphere. These small amounts of sulfuric acid can exist for months, reflecting the sunlight away from our planet. Therefore, temperatures are maintained at a lower level, in the low part of the atmosphere, as well as on Earth’s surface.
Research conducted earlier has revealed that volcanic eruptions in the beginning of the 21st century can be accounted for up to a third of the recent warming hiatus. In recent volcanic activity scientists have found observational climate indicators, the published study says.
1998 had the biggest temperatures ever recorded. The researchers explain that the following years have shown a stabilizing of the rising temperatures recorded in the 20th century. Although the recorded data shows a variation in the temperature rates, the warming hiatus at the beginning of the 21st century gathered a massive amount of attention, as scientists concentrated on explaining this phenomenon.
Previously, experts have suggested that the leveling of the warming rate was caused by high heat uptake by Earth’s water mass, or by the decrease of solar activity. In 2011, scientists first approached the idea that volcanic activity was partially responsible, and that even small eruptions can influence the warming process.
The new study shows that indicators of eruptions that took place at the end of the 20th century and at the beginning of the 21st, can be observed in the atmospheric temperature, its humidity and its reflected solar radiation. The phenomena of El Ninos and La Ninas facilitated a better observation of the climate signals due to their removal of climate noise.
In spite of their reduced size, the fact that the volcanic eruptions indicators are present in a multitude of climate variables that were observed autonomously, stands in support of the idea presented in the study, that volcanic activity can contribute to climate change.
Image Source: Places Under The Sun