One of the world's greenest office buildings will formally open its doors this week. It's a project of the environmentally progressive Bullitt Foundation. Its ambition is bold: to showcase an entirely self-sustaining office building hoping that others will create similar projects.

The first thing that strikes you about the new Bullitt Center is an emphasis on walking. "In a building this size, any place else in Seattle it would have two elevators. Here, the stairway is obvious and attractive,"says Denis Hayes, CEO of the foundation. He explains there is an elevator, but it's well-hidden. The staircase encourages exercise and the concept helps cut down on energy use.

This is one of dozens of visionary decisions that went into this building. "It has eyes, ears, a nervous system and a brain and it responds to its environment in a way that seeks to optimize （优化） things," he says. He points across the street to a mini weather station. It sends data to the building so it can decide what it should do to conserve energy.

"I think it's fair to say we were all a bit skeptical in the beginning, "says Chris Rogers, the founder of a firm in cooperation with the foundation. Rogers and the others set out to meet the ambitious goals of the Living Building Challenge, a green building standard set by local architects.

Clearly this building is not for everyone. If you think of it as simply an office building, it was relatively pricey to design and build. But if you view it as a laboratory, an educational center and a bold effort to change how things are built, the calculation changes.

Still, one could wonder, is it possible to build more with similar self-sustaining features at a reasonable cost? "If this building isn't reproducible, then this experiment will have failed, says Rogers. But if it is successful, he's optimistic others will follow the foundation's lead. Rogers points out that over the past couple of decades, many builders have been integrating green elements into their buildings.

If you dream of a world where neighbors share with each other and you don't have to spend money at a store every time you need something, then your local Buy Nothing Group might be the perfect fit. This clever idea began in July 2013, when two friends, Rebecca Rockefeller and Liesl Clark, from. Bainbridge Island, Washington, wanted to try something new. They liked the idea of developing a local gift economy as a way to challenge the consumerist mindset and reconnect neighbors. The Buy Nothing Project has grown rapidly since then, with 6,000 groups now in 44 countries.

The basic idea is that anyone can ask for what they need and anyone can give it. The official rules are simple: "Post anything you'd like to give away, lend, or share among neighbors. Ask for anything you'd like to receive for free or borrow. Keep it legal. No buying or selling, no trades, we're strictly a gift economy."

All participants have equal standing. Gifts and requests can be large or small, items or services (though they must be legal). Lending and borrowing are allowed, too. Things must be given freely, with no expectation of a gift in return. There are no rules about how to post, though people are encouraged to share personal stories about themselves, their gifts and requests, as this helps to build community.

When asked why the Buy Nothing Project has been met with such enthusiasm, the founders suggest it's because of the human desire to feel connected with others around us. Besides, this is truly a great way to take a stand against over-consumption, to clear out our homes, to save items from landfill and prolong their lifespan , and to keep valuable resources in the ground. The more sharing and reusing we can do, the better off we'll all be for both climate and human well-being.

Pioneers like Harvard social ecologist Stephen Kellert were among the first to champion modern biophilic design. Kellert believed that weaving nature into living and workspaces is critical for good physical and mental health.

Humans have evolved to gravitate towards nature, Kellert noted, but if we don't develop that impulse it fades. So his principles include access to natural light, air, water, plants, and gardens. Using materials such as wood and stone, natural designs such as leaf or shell patterns, and earthy colors also helps humans to feel closer to nature.

Biophilic designs can be seen in cities and buildings around the world. Modern examples include the Jewel Changi Airport in Singapore, with its four-storey forest garden and world's largest indoor waterfall fed by rainwater. Or the Swedish Mirrorcube tree house hotel, mainly made of used plywood and a lightweight aluminum (铝) frame wrapped around a tree.

Spectacular biophilic homes include One Central Park in Sydney apartment blocks featuring hanging gardens on the outside. The buildings recycle their own water and a suspended (悬浮的) motorized mirror system reflects sunlight down onto gardens below. Milan's Bosco Verticale block is perhaps even more eye—catching with its vertical forest of 17,000 trees, bushes, and plants.

Putting biophilic design to work for society could prevent millions in healthcare costs, with one study estimating annual savings of $93 million in the US alone. Hospital design in particular has historically been influenced by access to sunlight and views of nature. Modern buildings like the Khoo Teck Puat Hospital in Singapore, with its position next to the waterfall of the Yishun Pond, are closely linked with their surroundings. The hospital channels outdoor air to cool the inside, and uses reflective sunshades to direct light into the wards to brighten them and save energy.

The aim of these designs is to emphasize the human connection to nature by integrating buildings with the local environment. But how do we bring biophilia into our homes? Start with house plants. New smart home apps can also provide sensory nature experiences such as birdsong and a projected forest canopy, helping people to carve out a restful space indoors.

But perhaps the best way to transform society with biophilic designs is to start with schools. Children learn better and feel more relaxed in biophilic settings. So the Children and Nature Network is working with schools across the US to create green schoolyards for better physical and mental health and to increase opportunities for outdoor learning.

Biophilic designers are bringing nature into classrooms through natural patterns, shapes and colors, nature photography, artwork and materials like timber and stone. Fresh air flow, green walls, and aquariums all become part of a recipe for improving health and academic success.