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“Temperature blankets” are the new hot crafting craze.

Trina Messer knew the weather in Dallas-Forth Worth had been unusually warm this year, but she hadn’t anticipated needing her clay-colored yarn in February. “Today we are expecting a high in the 90s!!!,” she marveled in a Facebook update last week, adding regretfully, “I was hoping for more blues, but it is what it is.”
Messer, a retired educator of 30 years, started crocheting in 2022, the natural evolution of a knitting habit she’d picked up while bored during the pandemic. So far, she has made several scarves and hats, a big cardigan “almost like a coat,” and even a couple of throw blankets. Then, in January, she began work on her biggest project yet: a temperature blanket.
Temperature blankets aren’t always blankets — they can be scarves, shawls, and even crocheted snakes. The basic premise, though, is the same: Over the course of a year, knitters, crocheters, and embroiderers add a new row, stitch, or square to their project every day, with the color of yarn corresponding to the temperature of the location where they live. In recent years, this community has grown massive, in essence creating a de facto visual record of climate change for thousands of locations around the world. “From December 1 until today, I’ve had over 26,000 people join,” Sarah Moerdyk, the creator and moderator of Facebook’s largest temperature blanket group, told me in February. For most of its existence, beginning in 2017, the group wasn’t “super active,” hovering around a few hundred members. “In a matter of three months, it’s really blown up.”
Messer chose to break her earth-toned palette into 10-degree intervals, ranging from a white yarn that represents temperatures below 19 degrees Fahrenheit to “chili red” for days over 110. She even has a special yarn, “silver sparkle,” to log days with snowfall. Thankfully, she’d already purchased the clay-colored yarn she’d designated for temperatures between 90 and 99 degrees, even though she hadn’t expected to need it until late March or April.
According to the National Oceanic and Atmospheric Administration, the contiguous United States just concluded its warmest meteorological winter in recorded history. Across the country, temperatures were 5.4 degrees above average; in some states, like Wisconsin, it was nearly 10 degrees above what it should have been for the period between December and February. “This is not normal,” Messer told me a couple weeks ago, when her phone showed it was 91 degrees near Dallas. “Don’t think it’s like this all the time.”
Despite temperature blankets’ resemblance to climatologist Ed Hawkins’ famous warming stripes, the concept predates his 2018 graphics. Perhaps more surprisingly, it wasn’t initially conceived as a commentary on climate change. As far as I — and others — have been able to gather, Kristen Cooper, a craftsperson and beekeeper living in northern British Columbia, was the first to come up with the concept that evolved into the modern temperature blanket challenge when she described a similar scarf pattern in a 2013 blog post. “You record the day’s highest temperature by knitting one row in the color designated for each temperature,” she wrote. By the end of the year, “you will have a visual, colorful graph of the temperatures of your area.”
Cooper told me she, in turn, had been inspired by knitter and author Lea Redmond’s “sky scarf,” a project from 2008 (and later, a book) that involved knitting a row a day in a color that “best captures the essence of the sky out your window.” Redmond was slightly skeptical of the idea that she could be the temperature blanket’s progenitor. Her project tried to capture “the embodied experience of looking at this beauty of the sky every day,” she told me. Temperature projects, by contrast, rely on numbers that people retrieve from a thermometer in their kitchen — or, “I’m guessing, a lot of people just check the internet.”

Internet data doesn’t have the immediacy of events unfolding in real-time, outside your window. But representing temperature data at all requires a level of emotional remove that Redmond, personally, was a little wary of: For example, when wildfires turned day to night in California in 2020, “temperature-wise, that would not have shown up in a temperature scarf, but in a sky scarf, that stripe would have looked like shit.”
Cooper, for her part, never finished the first temperature scarf because she realized that if she missed a day, she couldn’t accurately make it up — her rural town didn’t have its own weather station — which would defeat the whole point of the project. But while she eventually moved on, swept up by life with a new baby, the knitting world took the concept and ran with it. “I hadn’t really been following along, but every now and then, a completely random post by strangers on Facebook or Instagram will pop up showing a temperature blanket,” Cooper told me. “And I’m always so amazed at how far the concept has traveled.”
Only recently have artists started using conceptual knitting and crocheting projects as explicit commentaries on climate change. In 2017, after the inauguration of President Trump, yarn shop owner Emily McNeil and data scientist Asy Connelly launched the Tempestry Project — which uses standardized colors and ranges to create historic temperature records — half as a joke and half out of real anxiety over the possibility of climate information disappearing from government websites. “We weren’t really thinking about temperature blankets,” McNeil told me. “I guess I knew that they existed, but it wasn’t really on my radar when we started it.”

Admittedly, sifting through all that climate data can take an emotional toll during the hours or days it takes to complete a tapestry. In addition to tapestries representing individual years, which rely on historical data rather than real-time observations, the Tempestry Project also facilitates multi-year “New Normal” tapestries that are directly inspired by Hawkins’ warming stripes. “The first one that I knit had me in tears as the colder colors just fade out, and you are never going to get those again,” McNeil said. (When I asked how they deal with the feelings brought up by the project, McNeil and Connelly told me dryly, “A lot of wine.”)
Temperature blanket knitters and crocheters can similarly feel alarmed by what’s unfolding in their hands. Moerdyk told me the warm weather in the northern hemisphere has been a big topic in the Facebook group, with some people having to quick-order summer colors or make special trips to the store to accommodate the winter heat in their projects. Perversely, the weirdness becomes kind of thrilling. “It’s fun to hear people say, ‘My colors are going nuts right now,’” Moerdyk said. Especially this early in the year, “to put all of a sudden this really warm temperature color in — it’s memorable. You’ll look back and say, ‘Oh my gosh, remember that time in February we had a 70-degree day? That was crazy.’”
The result is that temperature blankets become an accessible way of discussing climate change, without any of the political baggage. Moerdyk originally started the Facebook group for her friends but has since recorded participants from 1,114 different locations, including every state and over a dozen countries. She said the community has remained surprisingly civil despite all that diversity — some of it surely ideological. But temperature blankets are “not really a controversial topic,” Moerdyk said. “No matter what you believe in, temperature changes.”

For the thousands of hobbyists who’ve taken on temperature blanket projects, the craft becomes a way to witness the immediate changes in their environment that aren’t necessarily wholly negative. “If you’re looking at temperature blankets as a climate marker, that can get heavy,” Heather Walpole, the owner of Ewe Ewe Yarns, which sells temperature blanket starter bundles, told me. “But we’re still living our lives and we have a desire to create.”
Redmond, the sky scarf creator, finds this kind of creative intentionality to be the key. “It’s not like I invented stripes having meaning,” she joked. “But I do think most stripes on most garments in most stores in the United States today are meaningless. That just seems like such a missed opportunity.” It’s not that having a throw blanket or a scarf with weather-coordinated stripes will change the world. But displaying or wearing a beautiful object inspires others to ask questions: Where did you get that? Did you make it yourself? “They’re story sparks,” Redmond said. “They’re excuses to tell your story.”
This already weirdly warm year is still in its relatively chilly opening chapters, but the savviest knitters are already hurrying to stock up on yarns for June and July. As Messer, the Texas-based knitter, told me, “If this summer is anything like last summer,” then her blanket will have “a whole lot of burnt orange and red.”
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The data center boom is everywhere you look in U.S. economic and emissions data.
This is an edition of Heatmap Daily, an evening review of the day’s news written by our executive editor. Sign up for it here.
It isn’t exactly a new thought, but I’ve been struck recently by how many trends in America’s economic and environmental data are fundamentally about the data center boom and the return of electricity demand:
First, the Energy Information Administration reported this week that U.S. emissions grew by more than 2% last year, driven by surging electricity demand and an increase in coal-fired generation. What caused that higher power demand? New factories and data centers — as well as record summertime cooling demand.
Second, many of the new factories driving that higher power demand are themselves producing goods that are … let’s say … data center-adjacent. There are the enormous new semiconductor fabs, of course. But Ford and General Motors have also set up new production lines (or repurposed old ones) to manufacture grid-scale batteries to meet power demand.
Third, take a look at the recent U.S. spending on private non-residential construction — in other words, everything American companies are building that is not houses, condos, or apartments.
The construction industry’s spent almost $60 billion on data centers over the past year, which is more than it spent on all other office buildings combined (and more than it spent building warehouses, too). Just a handful of categories — data centers, power plants, electricity infrastructure, and certain kinds of electronics manufacturing — now make up a third of all U.S. private non-residential construction investment. They’ve never made up such a large share of construction spending since data collection began in 2014.
As The New York Times recently noted, the American economy is unusually dependent on the American stock market right now — and the stock market is unusually dependent on artificial intelligence. This week, investors started to balk at the enormous spending hyperscalers are planning to keep building out the AI boom; Alphabet’s shares dropped 8% this week after it boosted its planned 2026 capital expenditure and signaled 2027 will be even bigger. If the data center boom started to slow down in earnest, then more than just that budget will change.
Speaking of which, my colleague Emily Pontecorvo wrote earlier this week about how many businesses are struggling to even estimate their carbon emissions from artificial intelligence. The carbon accounting startup Watershed recently unveiled a new formula to help companies get a sense of their AI-related emissions.
But even that formula is still limited by the amount of data hyperscalers publish — and they don’t publish that much. Google, for instance, is the only AI company that has (laudably) provided estimates of its emissions on a per-prompt basis. Yet no company has published its per-token emissions, or how emissions sync up with particular models or regions.
So Emily asked Google: Why aren’t you — or any other model provider — disclosing this kind of data yet?
The tech company didn’t get back to us until after we’d published Emily’s story. But its response was interesting enough that I wanted to quote some of it here.
The problem is “industry consensus,” Cooper Elsworth, a Google spokesperson, told us. “There is currently very little consensus on how to comprehensively and fairly measure the serving environmental impact of generative AI (such as text generation),” he wrote. “Without standardized, ‘apples-to-apples’ frameworks, it is difficult to compare different providers accurately.”
That’s partly because energy use — and emissions data — can vary from site to site and depend on “custom-built hardware, software compilers, and advanced inference techniques.” And he claimed Google doesn’t always have the measurement hardware in place to provide such specific estimates: “Providing precise, repeatable data requires highly advanced measurement infrastructure,” he said. “For example, software-based energy monitoring tools often suffer from sampling biases. For our study, we had to step away from top-down averages and directly measure actual energy at the physical power supply unit (PSU) level across our deployed fleet. Not all providers have the telemetry or data sets required to benchmark their operations at this level of granularity.”
Read Emily’s story to understand the other reasons why estimating — or even “guesstimating” — AI-related carbon emissions is so challenging.
A conversation with Emma Uridge of the Kansas Health Institute.
This week’s conversation is with Emma Uridge, analyst with the Kansas Health Institute. Uridge spent copious hours analyzing state and local laws on data center development to best understand how policymakers are responding to the potential environmental public health impacts of large AI infrastructure, including power and water. The report, which came out this week, also goes in depth into those health impacts. I reached out to her to discuss what she sees as must-watch territory for our readers on this emerging policy arena.
Our conversation was lightly edited for clarity.
What is actually being done on policy when it comes to data centers — beyond moratoria of course?
So first I’d like to just talk about the point of moratoria. It’s helpful to talk about how these policies emerge in the first place. One area where moratoria are helpful is when a data center is proposed but the county has no approach for how they’d like to potentially regulate them. That’s temporary, most of the time. It lets local governments conduct research on the various impacts and also negotiate community benefits, ones that can mitigate any potential negative impacts — like Lancaster Pennsylvania, which instituted a community benefit agreement that maximized the potential benefits of development while mitigating what large data centers can do. That agreement looked at capping municipal water use at 20,000 gallons per day and requiring 100% clean energy. It had financial penalties for non-compliance. The company also committed $20 million to their local economic development and clean energy fund. There are ways to negotiate with developers.
We also see amendments to existing zoning. Data center proposals are increasingly popping up in rural areas, many of which are unzoned, so there’s no way a county can negotiate unless there’s a moratorium in place.
Other policy solutions include different performance standards or requiring on-site renewable energy, like what Jefferson County, Missouri, looked at. Also setback requirements, mandatory noise buffers, ending by-right zoning.
Where are local governments getting ideas for regulating data centers?
A lot of the technical information comes from developers. That can in cases be seen as a biased source of information. I wouldn’t say there’s a dedicated group providing assistance to local governments when a project is proposed — which is a similar story to wind industry development, where we have only a handful of consultants who provide technical advice. It can be really helpful to get a multi-disciplinary approach to hearing information. It can be helpful to have the utility commission, public health folks, those in academia, as well as the developer.
As of right now, especially in rural areas, local governments have a hard task of balancing pushback while getting the most accurate, evidence-based, neutral information to make decisions. That balance can be contentious.
What is the federal government doing on data center policy? How is the Trump administration approaching it?
A few things there. In the early days, the drive was for AI expansion and to be competitive with foreign adversaries. Now due to the amount of public pushback in red and blue localities and a more cautious approach.
I’m not seeing a lot of actual policy movement at this time.
I know the EPA is looking at the chemicals used in cooling data centers because when that water is cycled through the system, some of it is discharged into the water system, so they’re looking at the Toxic Substances and Control Act for monitoring that.
How much of an impact does this minimal federal role have on industry behavior?
Y’know, this isn’t specific to data centers. This is true for all kinds of large-scale development: there’s a need to require some sort of federal monitoring and regulation.
That’s where I see an emerging role for public health. At the federal level, there could be policy movement towards requiring some sort of environmental monitoring at data centers to make sure they’re operating responsibility. Looking at specific water use relative to water availability and what happens when there’s a time of severe, persistent drought. With air quality too — we’ve seen areas where the grid isn’t as reliable so their diesel generators are kicking on more and affecting air quality for residents.
We’re just not seeing all of that right now. We need corporate disclosure.
What do you see as the most important public health impacts from data center development?
It varies by localities. The most discussed obviously is water usage. One thing I’d note about my conversations with folks enthusiastic around emerging tech is, there are still questions that need to be asked about the capacity of localities to support a data center. Like a small town in Kansas may only be using 40% of their water for their utility needs. If a data center came online, how much of that water goes to the data center?
One area underexplored within the public health discipline is energy poverty and energy security. The ability of a household to meet the needs of everything energy provides in our lives. It’s known we have an aging electric grid but we’re not talking enough about large-scale blackouts when the grid is not sufficient to support some of these new data centers.
Plus more of the week’s big development fights.
1. Laramie County, Wyoming — Meta is fighting the fine it received in the Cheyenne data center water pollution controversy, and the conflict between the tech giant and the city’s small board of public utilities is continuing to spill out into the public.
2. Niagara County, New York — This county just rejected a solar project’s highway work permits in a show of retaliation against the state’s Office of Renewable Energy Siting.
3. Barron County, Wisconsin — The anti-solar protest is the new campaign stop in deep red Wisconsin.
4. Chesapeake, Virginia — A large battery storage project on the Virginia coastline is on the rocks amidst rampant local opposition.
5. Lewis County, West Virginia — West Virginia is now a key battleground in the fight over transmission, as a line spanning all of West Virginia and Maryland — and cutting through Data Center Alley in Virginia — causes compounding consternation.