Climate change will produce more rainbows

Double rainbow arching over a house and tree.
View at EarthSky Community Photos. | Jeff Marden in Berne, New York, took this image on September 19, 2022. Jeff wrote: “After a severe line of thunderstorms went by, we were treated to this double rainbow that lasted over 30 minutes.” Thank you, Jeff! Researchers said late last month that climate change will make rainbows appear more frequently.

Here’s some touching news. If you’ve ever been to Hawaii, you know it has an abundance of rainbows. And maybe it’s no surprise that researchers at the University of Hawaii at Manoa have been studying rainbows. But now their work has revealed something interesting. They said on October 28, 2022, that climate change will produce more rainbows in many places around the world. The study found that, by 2100, the average land location on Earth will have about 5% more rainbow days, compared to the beginning of this century. They said:

Northern latitudes and very high elevations, where warming is predicted to lead to less snow and more rain, will experience the greatest gains in rainbow occurrence. However, places with reduced rainfall under climate change – such as the Mediterranean – are projected to lose rainbow days.

The researchers published their study in the November 2022 issue of the peer-reviewed journal Global Environmental Change.

Why more rainbows with climate change?

Rainbows form when sunlight refracts through water droplets in the sky. Climate change is altering the patterns and amounts of rainfall and cloud cover on Earth. Taking these two facts into account, Kimberly Carlson, now at New York University, wanted to see how climate change would impact rainbows. Carlson said:

Living in Hawaii, I felt grateful that stunning, ephemeral rainbows were a part of my daily life. I wondered how climate change might affect such rainbow viewing opportunities.

The researchers found that areas of the world that are warming will see less snow and more rain. So these areas, such as mountainous regions or places farther north on the globe, have more chances for seeing rainbows increases. While drought will take away the rain necessary to produce a rainbow in some locations, overall, the chance for rainbows across the globe increases by an average of 5%.

Climate change: Double rainbow over forested hilltops.
View at EarthSky Community Photos. | Terry Simmons in La Veta, Colorado, took this image of a double rainbow on July 25, 2022. Terry wrote: “Thunder and rain descended upon us, then the sky opened up to a glorious double rainbow. Was unable to capture rainbow in its entirety as it was very large and long. I did try, yet I was able to capture one end over the Spanish Peaks.” Thank you, Terry!

Studying climate change

Studies on climate change are ubiquitous because most of these studies look at how Earth and the lives of humans will directly change. Camilo Mora of the University of Hawaii and Manoa said:

We often study how climate change directly affects people’s health and livelihoods, for instance via the occurrence of heat stroke during climate change-enhanced heatwaves.

But this study gave researchers a chance to examine how climate change would affect the aesthetics of our environment. Rainbows aren’t just a result of scientific elements coming together, but they provide an emotional component to our lives on Earth.

Carlson said:

Climate change will generate pervasive changes across all aspects of the human experience on Earth. Shifts in intangible parts of our environment – such as sound and light – are part of these changes and deserve more attention from researchers.

Mapping rainbows

The researchers mapped the occurrence of rainbows using images on Flickr. People from around the world shared photos of rainbows they’d taken, which the researchers sifted through. They created a rainbow prediction model based on location of the photo plus maps of precipitation, cloud cover and sun angle. Then they used this model to predict present and future rainbow occurrences over Earth’s continents.

In fact, one thing they learned is that islands are rainbow hot spots. Probably not surprising to those who live in the Rainbow Capital of the World.

Steven Businger of the University of Hawaii at Manoa said:

Islands are the best places to view rainbows. This is because island terrain lifts the air during daily sea breezes, producing localized showers surrounded by clear skies that let the sun in to produce majestic rainbows.

Climate change resulting in more rainbows gives another meaning to the saying that every dark cloud has a bright spot.

Map of the world with red areas showing more instances of rainbows.
This map shows the areas that could become rainbow hotspots with climate change. Also plotted is the change in annual rainbow days from circa-2000 to circa-2100. Image via Carlson, et al. 2022/ University of Hawaii at Manoa.

Bottom line: Researchers from the University of Hawaii found that climate change will bring more rainbows to higher latitudes and higher elevations.

Source: Global rainbow distribution under current and future climates

Via the University of Hawaii at Manoa

November 2, 2022

Like what you read?
Subscribe and receive daily news delivered to your inbox.

Your email address will only be used for EarthSky content. Privacy Policy
Thank you! Your submission has been received!
Oops! Something went wrong while submitting the form.

More from 

Kelly Kizer Whitt

View All