Since the dawn of consumerism, T-shirts have been the message boards of our culture. They purvey the mantras of our movements, the mottos and images of our pop culture, the logos of our corporate elite, and serve as affordable, wearable canvases for our artists. The 21st century sees the emergence of the green T-shirt, one donning eco-conscious slogans printed on environmentally friendly materials.

In the 19th century, the T-shirt was simply an undergarment for the working class. By the mid-20th century, Marlon Brando in A Streetcar Named Desire, WWII soldiers and perhaps, Don Johnson in Miami Vice, made the T-shirt more common and sexy as outerwear. Sociopolitical movements in the 1960s set the scene for T-shirts as a medium for messages and by 1977, marketing brains like Milton Glaser, who created the "I love New York" logo T-shirt, had realized that consumers were human billboards for their brand's advertisements. Now, as the T-shirt is practically the most common item of clothing in any individual's closet, the T-shirt's fabric, and providence, is becoming just as important as it's message.

"Global Warming is so Hot Right Now" is the slogan printed across all recycled T-shirts at Mu'umu'u Heaven in Kailua. The message is to inspire people to repurpose things before they toss them, according to owner Deb Mascia, whose store is founded on recycling and repurposing vintage clothing into one-of-a-kind dresses and accessories. Everything in the store is 100 percent recycled, "making new clothes with old clothes," as Deb says. In addition, Mu'umu'u Heaven donates one percent of their sales to coral reef conservation through 1% For the Planet.

"Our T-shirt line is 100 percent recycled," Deb explains, "which means the T-shirts are salvaged from local thrift shops and we print on them locally with non-toxic, water-based inks. They've had a former life and we've given them a new life." You can see the remnants of the former life under the printing on each repurposed tee. One such shirt has the ghost of a beer logo with a slogan still faintly visible underneath that reads: "The beer that makes you naughty!" This cheesy marketing beneath the repurposed global warming slogan makes the message that much more poignant. Celebrities Jackson Brown, Eddie Vedder, Jack Johnson, Chaka Khan, and Matthew Fox have been seen wearing the shirt.

Beyond old tees repurposed and upcycled to live again is a world of eco-friendly fabrics and materials. Local companies like Organik, Kealopiko, and Vers Hawaii are creating T-shirts that are not only promoting environmental awareness in their original imagery and text, but by simply reading the tags, can also provide an education in the ever-evolving sustainable materials being used today. These T-shirts can be made of repurposed material, organic cotton, bamboo, hemp, micromodal, milk, soy and post-consumer recycled plastic bottles.

"I have an environmental and public health background in addition to liking comfortable clothing, so it was only natural to use lightweight, breathable and vintage soft designer tees made exclusively from organic, sustainable and recycled materials," explains Ed Fernandez, co-founder of Organik, who uses certified organic cotton, sustainable materials such as bamboo, micromodal, hemp and fabrics made with post-consumer recycled plastic bottles for the Organik tees. Organik's original designs have different environmental messages like "Save Our Shore" or "Free Range" (complete with image of proud rooster), as well as nautical themes like "Organik Sailing Club."

In addition, low impact dyes can be used to add color to eco-friendly tees. These earth-friendlier dyes do not contain heavy metals or chemical mordants and have a better color absorption rate that requires less rinse water. "All of our artwork is screen printed on the tees with water-based inks for a soft-hand, vintage look and feel that are friendlier to our planet as opposed to plastisol inks made from harmful chemicals," Fernandez explains.

Eco-conscious is synonymous with Hawaiian culture, so it makes perfect sense that cultural-fashion company Kealopiko would have an organic T-shirt line as well. Their shirts don beautiful imagery along with traditional Hawaiian language phrasesóusually older grammar that is not as contemporarily used. "Our message is a cultural one, but also an environmental one," says Ane Bakutis, Kealopiko co-founder. "All of our designs are based on Hawaiian plants and animals and a lot of them correspond with rare or endangered birds, plants or fish in Hawai'i. We are trying to educate people on things that are authentically Hawai'i so that when people connect to these plants and animals, they realize they are our responsibility."

Each shirt in the Kealopiko line is an education. With each unique design is a background that illuminates the image with its Hawaiian history and folklore. For example, the "Pua V-neck," with schools of young fish swimming in formation across the shirt, inform those who are drawn to the shirt that the word "pua" actually has several meanings and that one such meaning is also a term used for the young of several fish species, especially 'anae (mullet fish). For Kealopiko's mission, the schools of pua on this shirt swim with the changing tide, their strength and success lies in their togetherness.

Roxanne Chasle-Ortiz and Matt Ortiz, partners in art, surf, and marriage and cofounders of Vers Hawaii, express a nature-centric, playful approach in their designs. Roxanne and Matt met as undergrads at University of Hawai'i at Manoa, majoring in art. As printmakers, they would screen print their designs on tees for the school's annual printmaking sale. The shirts became so popular that they continued to design and print them on the side after graduation. The hand-drawn designs, like the "Kalo Kruiser" T-shirt, are printed on organic cotton and tri-blend fabric.

"We love the T-shirt in Hawai'i," says Roxanne. "People here probably wear it more than any other place in the U.S., so it's nice to have that basic canvas for the art since it's a more democratic way to share what we do."

While green T-shirts tend to have a slightly higher price point due to the higher quality materials, Roxanne sees that people feel good about purchasing an item that has a smaller carbon footprint. "It was never a question when we began designing shirts that we would print on fabrics that were better for the planet," she notes.

And so, the T-shirt continues its evolution in the 21st century as more than a fashion trend or marketing tool. The green tee is an opportunity to not just wear the talk, but walk the walk by voting with your dollar in supporting a local, eco-savvy company that repurposes clothes or supports textile manufacturers who are committed to sustainable fabrics. After all, if you're going to be a walking billboard, might as well spread a positive message.