Climate change predicted to produce more rainbows

“Somewhere Over the Rainbow” will take on a whole new meaning in the next century, thanks to the climate.

Climate change will increase opportunities to see rainbows, giving the average land location on Earth 5% more days with rainbows by 2100 than at the start of the twenty-first century, according to a new study led by researchers at the University of Hawaii at Manoa.

Northern latitudes and extremely high elevations, where warming is expected to result in less snow and more rain, will see the greatest increases in rainbow occurrence. However, places with less rainfall as a result of climate change, such as the Mediterranean, are expected to lose rainbow days, according to the study.

Rainbows form when water droplets reflect sunlight, and are therefore dependent on sunlight and rainfall. Human activities such as the use of fossil fuels warm the atmosphere, altering the patterns and amounts of rainfall and cloud cover.

Camilo Mora of the University of Hawaii at Manoa’s Department of Geography and Environment was intrigued by the question and proposed it as the focus of a project for one of his graduate courses. 

“We frequently study how climate change directly affects people’s health and livelihoods, such as the occurrence of heat stroke during climate change-enhanced heat waves,” Mora says.

However, this study allowed researchers to investigate how climate change might affect the aesthetics of our environment. Rainbows are more than just the result of scientific elements combining; they also add an emotional component to our lives on Earth. 

The researchers did not go into great detail about how changes in the frequency of rainbows might affect our attitudes or wellbeing, but they did discuss the long shared history we have with rainbows, which have played a part in human culture worldwide since ancient times.

It’s also worth considering the bond that phenomena like rainbows, as well as mirages and auroras, form between humans and nature. Getting people to care enough about their natural surroundings to want to protect them is part of the challenge of successfully addressing the climate crisis. 

“Climate change will cause widespread changes in all aspects of human life on Earth. Shifts in intangible aspects of our environment, such as sound and light, are part of these changes and should be given more attention by researchers,” said Kimberly Carlson, the study’s lead author. 

The researchers behind the new study want to see more emphasis on the parts of our Earth system that cannot be touched or easily quantified, which may affect our wellbeing and sense of connection in subtler ways.