A new study on the effects of the Laki eruption, which took place in Iceland in 1783, has found that a heat wave in Western Europe in the same year was likely not caused by the eruption. The study, authored by Brian Zambri, Alan Robock, Michael J. Mills, and Anja Schmidt, investigated the “Laki haze” and its effect on Northern Hemisphere climate in the 12 months following the eruption onset. Vísir reported first.
“Laki haze” cooled Europe
The Laki eruption, which began in June 1783, lasted until February of the following year. The outpouring of gases from the eruption, including an estimated 8 million tonnes of hydrogen fluoride and an estimated 120 million tonnes of sulphur dioxide, caused what is known as the “Laki haze” over Europe, leading to widespread human and animal deaths, drought, and famine.
The Laki eruption in Iceland, which began in June 1783, was followed by many of the typical climate responses to volcanic eruptions: suppressed precipitation and drought, crop failure, and surface cooling. In contrast to the observed cooling in 1784-1786, the summer of 1783 was anomalously warm in Western Europe, with July temperatures reaching more than 3 K above the mean,” the report abstract reads. Scientists have long been puzzled about the heat wave which followed the Laki eruption, and this study suggests that it was caused by anomalous circulation and not the eruption. “We find that the warm summer of 1783 was a result of atmospheric blocking over Northern Europe, that in our model cannot be attributed to the eruption.”
Africa and Asia were affected
The study also points out that Africa and Asia faced large reductions in precipitation due to the Laki eruption, causing widespread drought and famine. According to the study’s authors, the eruption also increased the likelihood of an El Niño in the subsequent boreal winter. “Understanding the causes of these anomalies is important not only for historical purposes, but also for understanding and predicting possible climate responses to future high‐latitude volcanic eruptions,” the report’s abstract concludes.
Based on Icelandic research
Hera Guðlaugsdóttir, an Iceland geologist and climate specialist, has researched the climate impact of eruptions. She says the cooling effect of the Laki eruption minimised the intensity of the 1783 heat wave. “If the eruption had not occurred, the heat wave could have actually been much worse. The eruption caused cooling throughout Europe. It did not, however, prevent the heatwave, but caused it to be less severe.”
The hypothesis that natural variability was the cause of the 1783 heat wave was actually put forth by Icelandic Professor in Volcanology and Petrology Þorvaldur Þórðarson in a 2013 study. The new study is partially based on research conducted by Þorvaldur and other Icelandic scientists on the eruption, including the amount of sulfur molecules that emerged and historical sources about its development.