In 2003, powerful solar storms during Halloween set off a chain reaction that damaged the Arctic Ozone layer: Study explains how space weather triggered ozone loss

In 2003, powerful solar storms during Halloween set off a chain reaction that damaged the Arctic Ozone layer and led to an unexpected decline in ozone over the Arctic in the spring of 2004. Scientists found that solar storms, strong upper-level winds, and chemical reactions combined to reduce ozone by as much as 60 percent. The findings improved understanding of how space weather and atmospheric conditions can influence Earth's protective ozone layer.