Red between the lines: What do your city’s climate stripes look like?

London Fashion Week, a bridge in Brisbane and the Pope have all, in different ways, showcased the climate stripes: a unique pattern of vertical, coloured bars, representing the progressive heating of our planet.

Created by British climate scientist Ed Hawkins at University of Reading in 2018, new experiments are taking this chart forward. But first, a bit on the data-visualisation effort. Hawkins’s graphic is a vivid representation of how global average temperatures have risen over about 150 years.

Individual charts have been created for 200 countries, some cities, each of the inhabited continents, and the planet overall. Because of their uniquely vulnerable positions, separate ones are available for the Caribbean Islands, Pacific Islands, Middle-East, and the global oceans as a whole.
In India, there are visual representations for 67 cities, ranging from the prime metros to a geographic spread that includes Gorakhpur in Uttar Pradesh, Kota in Rajasthan, Nabarangpur in Odisha and Warangal in Telangana.
The charts use, as their foundational data, open-source information on annual average temperatures between 1875 and 2023. (Global warming in general is measured as the rise from 1850s levels, which are the last years considered indicative of pre-industrial levels).
They are accessible on the University of Reading microsite showyourstripes.info, and are free to use.
Here’s how the colours take shape. Each stripe on a chart represents a specific year. Its colour is determined by how the average temperature of that place in that year compared with the baseline average.
Across the board, the charts have ended up looking like a barcode designed to go from blue to red. In most cases, the blue that represents a cooler-than-average year becomes all-but-invisible by the 1980s.
Unlike most data visualisation efforts, the climate stripes offer no additional figures, words or explanations. It’s scientific but simple, Hawkins has said on his blog, because it is meant to be accessible to everyone, and to have a striking visual impact.
The approach seems to have worked. In addition to the charts being beamed onto public monuments and used on climate-crisis book covers, the simplicity and impact have spawned an annual Show Your Stripes Day celebrated on June 21.
On this day, the stripes have been displayed at Times Square in New York, on London’s Tate Modern gallery, on the White Cliffs of Dover and the Story Bridge and Victoria Bridge in Brisbane. The patterns have also turned up on ties, dresses and face masks; and on electric trams and buses. And, last year, Pope Francis called for greater solidarity in the fight against climate change, after being gifted a climate-stripes scarf by an Italian news outlet.
Stripe a chord
With 2023 confirmed as the world’s hottest year on record, the latest global climate stripes image uses the darkest red on the current scale. It is unclear how further warming will be represented, but sending this message was important, Hawkins has said.
“(The warming) is in line with what scientists have been predicting… But the margin of record breaking in 2023 has still been a surprise,” Hawkins said in a statement in January.
Meanwhile, other attempts are taking the idea of climate stripes hyperlocal, which is interesting because the stripes originally started out small, before they went global.
Hawkins first presented the design at the Hay literary and arts festival in the UK, as part of a talk on climate-change communication. That first chart represented local data for the small Welsh town of Hay-on-Wye. After the festival, he shared the image on Twitter.
There, it drew the attention of American researchers and mushroomed into an online campaign that saw US weather presenters wearing stripes on their ties and mugs. From there, the idea began to make its way around the world.
But, as effective as the chart is, “when talking about climate change, one of the things we get asked the most is ‘Okay, but how is it affecting my local area?’,” says climate scientist Jared Rennie.
His approach to climate charts aims to help individuals generate the answer to that question themselves.
Rennie, who works with the National Centers for Environmental Information (NCEI), which is part of the US National Oceanic and Atmospheric Administration (NOAA), has developed an online geographic information system (GIS) tool that can generate warming stripes as well as precipitation stripes (with green bars for wet years, and brown for dry ones) for every county in USA. The tool draws on NCEI data from 1895 to 2023.
These visuals, he says, show how warming is not consistent across counties. They show how El Nino and La Nina play a role. And they offer clear evidence that, even at the micro level, the red is getting redder and more prominent, across the board.
In the next phase of his project, Rennie plans to break things down further. He wants to find a way to represent, for instance, how overnight minimum temperatures are rising faster than daytime maximum temperatures, at the local level.
This matters because “what was once the ability to cool off overnight is now no longer the case,” he says. This is concerning for wildlife; for energy companies who could once count on night-time dips in demand; for farmers and herders; for people with cardiovascular conditions.
And it is concerning, of course, for us all.