A supermassive black hole in the core of the Milky Way last erupted two million years ago, and will again.
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I’d like to return briefly to the topic of science, and explore further the difference between “science” as in “what researchers do” and Science (with a capital “S”) as in “what researchers have told us.” The first is a way that we …
NATGEO | 10 Green-Tech City Solutions for Beating the Heat
City Forest, Singapore
Photograph by Wong Maye-E, AP
Using plants and trees in a unique way,…
City Forest, Singapore
Photograph by Wong Maye-E, AP
Using plants and trees in a unique way, Singapore officials opened Gardens by the Bay this year. The 11-million-square foot (1-million-square-meter) complex—the size of nearly 250 U.S. football fields—aims to curb the heat island effect while bringing botanical bliss to urbanites.
The centerpiece of Gardens by the Bay is a glass atrium that houses approximately 220,000 types of vegetation, or 80 percent of the world’s plant species, according to Singapore’s National Parks Board.
Outside the menagerie of plants is a grove of 18 “supertrees”— vertical gardens up to 164 feet (50 meters) tall that capture rainwater, filter exhaust, and are capped with solar panels that provide enough energy to light up the trees at night.
The heat island effect occurs in cityscapes characterized by pavement, asphalt, and concrete—all materials that can absorb warmth. The annual mean temperature of a city with one million people or more can be up to 5.4°F (3°C) warmer than surrounding rural areas, according to the U.S. Environmental Protection Agency (EPA). The effects cascade as summertime peak energy demands rise along with air conditioning costs and greenhouse gas emissions.
(Test your A/C acumen with our quiz: What You Don’t Know About Air Conditioning.)
The value of vegetation in urban areas goes beyond cooling and shade. City plantings can also help improve air and water quality through filtering mechanisms.
A new study in the journal Environmental Science & Technology shows that grass, ivy, and other urban plantings, in addition to trees, can reduce levels of nitrogen dioxide and particulate matter by as much as 40 and 60 percent respectively. Both are pollutants that are potentially harmful to human health.
(Read more about the water quality benefits of vegetation in National Geographic News’ “Philadelphia Cleans Up Storm Water With Innovative Program.”)
Greening Government Buildings, Berlin
Photograph by Robert Wallis, Corbis
The Reichstag, Germany’s parliament building, was retrofitted in 1999 with a new dome that uses glass and mirrors to reflect daylight deep into the main chamber, reducing dependence on artificial lighting. It also employs a funnel to divert and collect rainwater.
Designed by British architect Norman Foster, the renovated Reichstag has become a Berlin tourist attraction and an energy saver.
The dome-reflector system also draws warm air out of the building. This feature, combined with the fact that the building can make its own electricity from refined vegetable oil, as well as store excess heat underground, brings the building’s carbon dioxide (CO2) emissions down by 94 percent, according to the architect.
Green buildings have myriad benefits, including reductions in greenhouse gas emissions, water use, and toxic materials use, improved air and water quality, and relief from the heat.
In the U.S. there is a debate brewing on Capitol Hill about how to define a green building.
The U.S. government requires all new federal construction to follow the U.S. Green Building Council’s (USGBC) requirements for a gold rating.
USGBC ratings—certified, silver, gold, and platinum—are awarded based on several factors, including sustainable site development, water savings, energy efficiency, and materials selection.
But, to the disappointment of some chemical and plastics companies, the USGBC’s rating system is expected to change next year and may discourage builders from using some products such as PVC piping. A coalition of chemical and plastics manufacturers is lobbying Congress to use another set of criteria.
(See how the U.S. government has gone green in National Geographic News’ “Pictures: Seven Supergreen U.S. Government Buildings.”)
Floating Food, New York
Photograph by Tyrone Turner, National Geographic
The Science Barge is a floating environmental education classroom and greenhouse on the Hudson River in New York.
Fueled by solar power, wind, and biofuels, the barge, which was built in 2007, has zero net carbon emissions.
Vegetables are grown hydroponically—with plants getting all of their necessary nutrients from water instead of soil—in an effort to preserve natural resources and adapt to urban environments, where healthy soil, or soil at all, is hard to come by. Rainwater and treated river water are used for irrigation, and pesticides are prohibited.
The original owner of the barge—New York Sun Works—designed it as a prototype for closed-loop and self-sufficient rooftop gardens in urban areas.
(See more pictures of urban agriculture in “Urban Farming Is Growing a Green Future.”)
Thousands of schoolchildren and adults have visited the barge, which is now operated by Groundwork Hudson Valley and docked in Yonkers, just north of New York City.
Sustainable Housing, Denmark
Photograph from Yonhap News Agency/European Pressphoto
There are no official global standards for green buildings, but hundreds, if not thousands, of examples of sustainable construction are found internationally.
8 Tallet—Danish for 8 Houses—surpasses the capacity of most other green housing developments in Denmark, and the world.
Designed by the Bjarke Ingels Group, the suburban housing development—about a ten-minute train ride outside of Copenhagen—has nearly 500 apartments and incorporates a commercial district, so that residents don’t need to burn fossil fuels to shop for groceries or lounge at a cafe.
The buildings, officially opened in 2010, are oriented to capture as much daylight as possible, and an elaborate 18,000-square-foot (1,700-square-meter) green roof helps to deflect harsh rays and keep the grounds cool. Traditional tar-based or black urban roofing materials contribute to the urban heat island effect by absorbing heat and raising city temperatures.
Solar Dominance, China
Photograph by Liang Baohai, Imaginechina/AP
The Sun-Moon Mansion is headquarters for what could become the biggest solar energy production base in the world, or the Silicon Valley of solar.
The office building, conference center, and training facility is the home of Himin Solar Energy, the world’s largest maker of solar water heaters. The company was founded by oil equipment engineer Ming Huang, a member of China’s Parliament known as the “Sun King.” Huang has expressed concern about a fossil fuel-dependent economy, and is working to transform the area around the Sun-Moon building into China’s Solar Valley.
The 807,000-square-foot (75,000-square-meter) headquarters also features insulation techniques that will help the structure achieve energy savings up to 30 percent higher than the national standard.
China is on a mission to meet 15 percent of its energy needs with renewable sources by 2020. The country is currently at 9 percent.
Photograph by Marco Bulgarelli, Gamma-Rapho/Getty Images
It takes a village … to truly go green. Quality of life and sense of community are key at the BedZED eco-village in London. Private developers completed the mixed-use community in 2002, making it the first such community in the United Kingdom. The village comprises a hundred homes and enough office space for a hundred workers.
With a rooftop garden, reclaimed building materials, efficient insulation, solar panels, ramped up recycling rates, and a very short commute, BedZED residents reduce their carbon footprint by nearly 50 percent, according to development partner BioRegional
Air Tree, Spain
Photograph from Art on File/Corbis
“Air trees” in the Madrid suburb of Vallecas are self-sufficient gardens that produce excess oxygen and energy.
Made from recycled materials, the air trees provide respite from summer heat with shade and natural ventilation. Solar energy collected by photovoltaic panels on the trees’ canopy is used to power sprinklers and other aspects of plant maintenance. Additional energy is fed back into the region’s electrical grid.
The trees were first installed in 2007.
(Read more about vertical gardens in National Geographic News’ “High-Rise Farms: The Future of Food?”)
Wind Tower, Abu Dhabi
Photograph by Ali Haider, European Pressphoto Agency
The Masdar Institute wind tower, just southeast of Abu Dhabi, is part of a planned city being built by the Abu Dhabi Future Energy Company with the help of government funding.
British architects at Foster + Partners aim to create a city that is 100 percent powered by renewable energy technology and produces zero waste. Masdar City, when completed, will be the “global center of future energy,” according to developers.
The wind tower circulates cool, carbon neutral, air throughout the grounds of the Masdar Institute of Science and Technology.
Low Carbon Campus, United Kingdom
Photograph by Ashley Cooper, Corbis
The section of England’s Northumbria University called City Campus East was one of the first buildings in Europe required to meet new green standards coming out of the United Nation’s 1997 Kyoto Protocol to reduce greenhouse gases and combat climate change.
Opened in 2007, City Campus East provides housing for up to 9,000 students. In 2011, the building won the title of Low Carbon New Build Project of the Year—an award handed out by the U.K.-based Chartered Institution of Building Services Engineers.
An Eco-Village, United Kingdom
Photograph by Matt Cardy, Getty Images
The Wintles estate in Shropshire, England, may look like your average suburban housing development, but the homes here are among the most energy efficient in the U.K.
Houses, apartments, and other residential dwellings account for just under 30 percent of the country’s carbon emissions, so the government is encouraging people to live in eco-villages such as Wintles.
Photograph by Diane Cook and Len Jenshel