Seasonality of sex ratio at births in Iceland and effects of the 2010 Eyjafjallajokull volcanic eruption

Abstract

Males are born slightly in excess of females. This ratio is conventionally expressed as M/T (male/total births) and varies seasonally. Many factors influence M/T including violent natural events, such as earthquakes, severe smog and floods. Volcanic eruptions are natural disasters that threaten health, livestock and property. During eruptions, local populations may require evacuation, naturally inducing stress. Nordic data show an increase followed by a decrease in M/T in the 20th century. The April 2010 eruption of Iceland’s volcano Eyjafjallajokull was particularly violent, with fine-grained ash ejected up to 10 km into the atmosphere, disturbing air traffic all over Europe. This resulted in unprecedented disruptions to European air traffic during the 15th–20th of April 2010, costing the aviation industry an estimated $250 million daily. This study was carried out to ascertain whether M/T in Iceland exhibits a seasonal pattern, and whether the Eyjafjallajokull eruption resulted in any significant fluctuations in M/T three to five months after the event.