EarthTalk – What's behind Warming Stripes?

Title card for the EarthTalk environmental column showing a green glass globe.

Roddy Scheer & Doug Moss

Dear EarthTalk:
What’s the backstory on the so-called “Warming Stripes” visual display of climate change?
H.L., via email

In the past decade, warming stripes have become increasingly well-known data visualization graphics representing abnormalities of annual, monthly or historical temperatures for a given location. The vertical or occasionally horizontal stripes each represent a month or a year, and the color signifies the direction of deviation of the temperature from the average, with blue as cooler and red as warmer. The color’s darkness shows the size of deviation of the actual temperature from the baseline average. Much of the warming stripes' popularity is due to their easy-to-understand yet enticing appearance.

The story of warming stripes began in 2017 when Professor Ellie Highwood of the University of Reading crocheted and posted her global warming blanket on Twitter. Each row represented the average temperature change from a baseline average. The stripes contained many more colors, including pink, green, and yellow, than the current model. A year later, Highwood’s coworker Ed Hawkins narrowed down the colors to mostly blue and red to simplify the model. Hawkins later tested his model at the Hay Festival in the U.K. and received widespread support, prompting him to launch a website in 2019.

Hand drawing a line around the words "Climate Change" with surrounding words and images showing impacts — © iStock - tumsasedgars

When the website first launched, there were over a million downloads within the first week, allowing ordinary people to participate in the climate action campaign. Co-founder of Cycling for Climate, an organization using cycling to raise awareness of climate change, Joost Brinkman said, “It's an easy conversation starter, and people are always shocked when they understand the story." The company has since adopted the stripes as their uniform pattern. Additionally, renowned climate activist Greta Thunberg used the stripes as the cover of her work, The Climate Book. Some issues of The Economist also feature warming stripes as the front page. Warming stripes were also displayed at the Reading & Leeds music festival in 2021.

The popularity of the warming stripes culminated in the celebration of Show Your Stripes Day, an annual observance around the 21st of June that encourages people to post their region’s stripes across various social media platforms. It raises awareness of climate changes and encourages people to take action, whether on a large-scale or a small community level. Readers can participate in the warming stripes movement by posting our region’s stripes on Show Your Stripes Day each year. At the same time, we can engage with other people’s posts to start conversations, capture more attention, and encourage friends and family to participate as well.