The Road to Regeneration
From plastic bottles to the bricks and concrete that make up our buildings and roads, materials determine the form and function of everything we experience in the world around us and every product we use to fulfill our needs.
However, the way we currently produce and use materials is so wasteful and toxic that we’re degrading the planet beyond its ability to repair itself, with all that implies for humanity’s survival. In 2021, “Earth Overshoot Day,” the day on which humans use more natural resources than the planet can regenerate in a year, arrived on July 29, earlier than ever. In other words, humanity now needs 1.7 Earths just to satisfy its demands.
This situation is not just unsustainable; it’s permanently altering our environment. The weight of every human-made thing that exists, from the biggest ocean vessels to the smallest electronic components, now equals all living biomass combined. If current trends continue, this “anthropogenic mass” will outweigh the natural world threefold by 2040. And the output of all this human activity has a negative environmental impact disproportionate to its size: we produce more than 350 million metric tons of synthetic polymers (plastics) each year, but 76% of all plastic ever produced is lying unused in landfills, floating in the oceans, and defiling the natural environment.
But there’s hope for a more sustainable future. Researchers and innovative companies are rethinking the materials that businesses use throughout their operations. They understand that we can no longer separate how materials are used from how they’re sourced and disposed of – so they’re creating better alternatives for existing needs, designing materials to do more than is currently possible, and inventing materials that are less harmful to the planet and even actively help regenerate natural ecosystems.
Finding alternatives for plastics and textiles – and harvesting carbon emissions for new uses
To remove conventional materials from supply chains, we need to find sustainable alternatives that perform at least as well, if not better. After all, so much plastic exists because it is lightweight, durable, relatively low-cost, and can be used in a multitude of ways.
In fact, the plastics problem is a leading target for improving materials use. Many possibilities are emerging for developing durable but biodegradable bioplastics. One approach involves diverting food waste, with promising experiments involving whey protein, citrus peels, mango leaves, lobster shells, fish oil from salmon processing scraps, and soybean oil byproducts. Other sources of biopolymers come from beyond the plate and pantry, like cellulose, which makes up the cell walls of plants, and mycelium, the root network of fungi. There’s even a company that crushes stone to extract calcium carbonate, one of the most common minerals in the world, and uses it to replace up to 80% of the plastic in chip bags, candy wrappers, and other packaging so it degrades in months instead of centuries.
Another material that needs to be made more sustainably is concrete. Traditionally, concrete is made by binding gravel and fine sand with a paste of cement (made of limestone and ash that have been burned together and ground up) and water. Its strength and durability make concrete the most widely used human-made material on the planet, but making it consumes about 10% of the water used worldwide for industrial and commercial activities and emits about 8% of global CO2 emissions. But researchers have discovered that replacing up to half of the sand, which is expensive and carbon-intensive to produce, with waste clay dug up during excavation work, makes a super-concrete that’s both stronger and diverts construction material from landfills. Another new approach to concrete involves combining lime binder with fast-growing hemp plants to create a renewable, carbon-sequestering “hempcrete” that weighs eight times less than standard concrete and is ideal for non-structural uses like borders or sidewalks.
There’s ample room to rethink other construction materials, too, as well as how to use them to design buildings with smaller ecological footprints. Renewable bio-based alternatives to standard building materials might include nanocellulose insulation that’s stronger and more effective than Styrofoam, transparent, heat-retaining wood made with citrus peel waste, and engineered wood products that are as strong, stable, safe, and as versatile as concrete and steel. There’s also lightweight, flexible, emissions-free construction board made from cellulose extracted from paper recycling waste that would otherwise be discarded, and wood made from hemp that’s been bioengineered to be as durable as oak, but to grow 100 times faster. And nanotechnology has enabled graphene-based construction materials that enhance solar protection, deflect wind, kill germs, and more, actively improving the buildings’ immediate environments.
In addition to shelter, we need clothing, furniture, and bedding. But textiles and fabrics are often unsustainable. If the fashion industry continues its current practices, it will create an estimated 148 million tons of waste by 2030, or 38.5 pounds (17.5 kilograms) of waste for every person on the planet. We’ll need eco-friendly alternatives that create less waste during production, like fast-growing hemp as a cotton substitute or artificial leather made of mycelium fibers.
Other industries are also rethinking materials use. Take aerospace, for example. Researchers recently announced they had developed a new aerogel that, while not made from particularly green materials itself, is so lightweight that it would significantly cut fuel consumption in the next generation of aircraft – while also reducing noise pollution from the engine, both inside and outside the cabin. Another recent development in construction involves ultra-white paint so effective at reflecting sunlight and infrared heat that it actually makes surfaces cooler than their surroundings. The scientists who developed it speculate that giving buildings a lightweight, hyper-white coat of paint could be enough to significantly reduce the need for electricity-hungry air conditioning.
We’ll also turn more waste into value by capturing carbon belched from smokestacks. By turning it into black inks, paints, and coatings, or embedding it in carpet tiles that also use recycled vinyl, waste vegetation, and salvaged nylon, we can create durable products that move greenhouse gases out of the atmosphere for years, if not decades.
Finding more sustainable materials for our present-day needs is just the beginning. Materials scientists are going further by creating and using materials that expand on what’s possible.
Materials with future potential
As we investigate the properties of more renewable materials, we will find uses for them that aren’t possible with materials we’re familiar with today.
For example, when certain common ocean bacteria eat a combination of gelatin and sand, they turn into a mass of living concrete that can repair and reproduce itself. This material has promise for rebuilding after disasters and providing shelter quickly in challenging conditions. Scientists think they could even teach it to make oxygen and water, which would be useful in harsh environments – not just on Earth, but on other planets, should NASA realize plans to send crews to settle Mars, for example. Similarly, researchers are working on making building materials and tools by combining chitin, a biopolymer produced by fungi and insects, with other materials that are readily available.
Plants will also inspire new material properties. A lightweight, breathable textile made of cellulose fibers and seaweed could be able to infuse nutrients through skin contact, for clothing that nourishes the person wearing it. A genetically tailored kombucha tea starter that can sense pollutants and produce glow-in-the-dark enzymes could potentially be an eco-friendly biosensor indicating a package has been tampered with. Plants infused with nanoparticles that turn energy from photosynthesis into light could replace lighting fixtures with ambient off-grid lighting that also freshens the air.
In addition, researchers are creating partly organic and non-organic animate materials that are capable of sensing and adapting to their environments. Buildings made from these materials would be able to harvest light, water, heat, bacteria, greenhouse gases, and biowaste from their surroundings and inhabitants, then use those resources to maintain and repair themselves while generating useful outputs like power, oxygen, heat, and drinkable water. Equipment in industrial facilities could be made from self-repairing plastics and self-diagnostic coatings that simplify maintenance. Products could be programmed to disassemble themselves at end-of-life so their basic components can be recycled or repurposed. Even clothing could be made with animate materials that respond to people’s vital signs to keep them comfortable or detect possible illness.
Regeneration: The next frontier
In the search for a sustainable materials future, the ultimate outcome could be a broad shift to materials that aren’t just lower-impact, but that actively regenerate the environment and systems they are part of. That could mean designing materials that sustain themselves, restore nutrients to the environment as they break down, or actively remove existing waste from the environment as they’re created. Researchers in the Netherlands recently mixed microalgae with bacterial cellulose to create a “living material” that can be 3D printed into sturdy, biodegradable objects that sustain and regenerate themselves through photosynthesis. One potential application is artificial leaves that, given water and CO2, emit oxygen and store energy as sugars that can be harvested for fuel.
Living materials like this could also be formed into artificial skin that speeds healing by flooding a wound site with oxygen before dissolving – or fabric that requires less water than cotton to produce, purifies the air through photosynthesis, and returns nutrients to the environment when it biodegrades.
People who prefer less literal active wear may choose instead to wear textiles made from repurposed agricultural waste, and that break down at end of life to return nutrients to the environment. According to the EU’s Reflow Project, these garments could come from pineapple leaves, coconut water, or crustacean shells combined with citrus byproducts or coffee grounds.
When it comes time to package all of these products, we can feed sewage sludge and agriculture wastewater to hungry bacteria who excrete it as biopolymers that can be made into biodegradable plastics. Sourcing plastics this way could remove a sizable amount of sewage sludge from landfills – 2,500 Olympic-sized swimming pools’ worth is produced annually in the United States alone – and when those bioplastics dissolve or are recycled into their individual components, we can reuse, recycle, and reform those components into more sustainable materials.
The future of materials isn’t just about making man-made items more durable or designing them so that they can be upcycled or retired with less harm to the environment. It’s a fundamentally different paradigm. Ultimately, the future of materials requires us to leave behind our unsustainable system of resource extraction, processing, consumption, and disposal in favor of one where our materials restore and/or repair the damage we have done to the planet.
In other words, it’s not enough to travel down the wrong path more slowly. We need to take a different path – one that actually improves the quality of life for humanity and all other living things.