How Knitting Enthusiasts Are Using Their Craft to Visualize Climate Change

In these crafters’ scarves and blankets, rows of color correspond with daily temperature

Tempestries representing daily high temperatures in Utqiagvik, Alaska, in 1925, 2010, and 2016 (left) and Death Valley, California, in 1950 and 2016 (right) Justin Connelly via Wikimedia Commons under CC BY-SA 4.0

Earlier this month, writer Josie George shared a snapshot of a scarf she’s knitting on Twitter. At first glance, the accessory’s color pattern appears random, its shades of blue and yellow alternating with no evident pattern. But as the tweet and accompanying color key indicate, a very intentional method guided George’s color choices: Each row represents the daily recorded temperature in her hometown.

“It felt like a good way to engage with the changing climate and with the changing year,” explained George. “A way to notice and not look away.”

More than 56,800 people retweeted her creation, and thousands of others responded in kind, sharing snaps of their own temperature blankets and scarves.

While the specific techniques and materials used by this community of knitters, quilters and crafters vary, members shares a common goal: tracking weather patterns on specific dates. These projects, reports Grace Ebert for Colossal, are part of a movement that aims to “document micro weather changes” and highlight broader climate issues.

Unlike graphs depicting climate change data, temperature blankets and scarves offer a tangible representation of the global phenomenon—and add a personal touch to a technical subject. By knitting row after row of climate data, crafters break down climate change into more digestible parts that are easier to process.

“Knitting the years day-by-day has been a great way to break things down into small bits so the whole isn’t so overwhelming,” knitter Christine Armer told Fast Company’s Katharine Schwab last year.

Speaking with the Huffington Post’s Premila D’Sa, Justin Connelly, co-founder of the Tempestry Project, says temperature knitting “has been around for a long time.” The group, whose name is a portmanteau of “temperature” and “tapestry,” simply made the practice “into a systematic thing where everyone is using the same color for the same temperatures.”

Tempestry color key
Tempestry color keys for Fahrenheit (left) and Celsius (right) Justin Connelly via Wikimedia Commons under CC BY-SA 4.0

Woven with specially manufactured yarn kits, Tempestries are a “visual embodiment of a year’s worth of daily high temperatures,” as recorded in publicly available climate data published by the National Oceanic and Atmospheric Administration (NOAA). Per the project’s website, specific colors represent temperatures in 5-degree increments ranging from -30 degrees Fahrenheit to more than 121 degrees.

At the Schuylkill Center for Environmental Education in Philadelphia, a collection of Tempestries created by 30 local knitters and crocheters tracks the city’s temperature over a 143-year period. On its own, the knitted scarf depicting Philadelphia’s climate in 1875 is merely an eye-catching garment. But when placed next to a scarf representing 2018, viewers come to an alarming realization: A dark, fiery red yarn appears much more frequently in the 2018 Tempestry. The takeaway, explains Jimmy McGinley Smith for Grid magazine, is that Philadelphia has experienced multiple record-breaking weather events since 2010. Warm days are hotter and more numerous, while cold days are far fewer.

Tempestry at Schuylkill Center
A Tempestry on view at the Schuylkill Center in Philadelphia Courtesy of the Schuylkill Center for Environmental Education

On its own, climate change data is often too technical to be engaging, too formal to go viral. When incorporated into art, including colorful garments and scarves like Tempestries, this information becomes much more engaging. In 2015, for example, marine scientist Joan Sheldon presented a temperature scarf archiving data from the 1600s at a scientific conference. Though attendees were already familiar with the data, they still wanted to touch the crocheted creation.

“They never would [do this] with a science graph,” Shelton told Fast Company.

This 21st-century crafting movement is far from the first of its kind. Historically speaking, knitting and quilting have long been used to record data and embed information. An upcoming exhibition at the Eiteljorg Museum in Indianapolis shows how early 19th-century women used quilts to express personal stories and build visual records; during World War I and World War II, spies knitted encoded information and hidden messages into fabric. Like these traditions, climate scarves and blankets conceal information in plain sight, playing with the concept of “steganography,” according to Slate’s Rebecca Onion, to preserve data in a physical way.

As the movement continues to spread via social media and word-of-mouth, the inventory of collective climate change data keeps growing, making it harder to ignore.

“That’s kind [of] what we wanted,” Connelly told Gizmodo’s Maddie Stone in 2018. “We want people to take our framework and develop their own collections, this large mosaic of international climate data that can be compared and contrasted because it’s all the same color scale.”

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