Stephen Ritz: A teacher growing green in the South Bronx. Smog-eating tiles gobble up air pollution. U.S. company Boral Roofing has introduced a line of roof tiles that it says have pollution-busting properties.
The company says chemicals in its smog-eating tiles react with nitrogen oxides released by vehicles, extracting them from the air and cleaning up the atmosphere, as this cartoon shows. The tiles are coated with titanium dioxide, a photocatalyst, activated by daylight, which reacts with nitrogen oxides in the air turning them into harmless calcium nitrates, as this cartoon shows. When it rains the calcium nitrate -- a regular garden fertilizer -- is washes off the roof, as this cartoon shows.
Los Angeles has the highest levels of ozone pollution of any U.S. city, according to 2012 rankings by the American Lung Association. Exposure to urban air pollutants can increase the risk of cardiovascular diseases and cancer as well as trigger asthma attack, according to the World Health Organisation. The downtown skyline of Los Angeles is enveloped in smog shortly before sunset. Smog city. Solar-powered 'supertrees' breathe life into Singapore's urban oasis.
Singapore's 250-acre green development, Gardens by the Bay, is part of Singapore's redevelopment and new downtown area at Marina Bay.
It features three waterfront gardens -- Bay East, Bay Central and Bay South, which opens to the public on June 29. In contrast to the dense urban environment of skyscrapers and high-rise buildings in Singapore, Gardens by the Bay is part of the government's overall strategy to transform Singapore into a "city in a garden. " The Cloud Forest biome is the larger of two climate-controlled conservatories. Can oxygen pump breathe life into ocean 'dead zone?' A satellite image of "summer blooms" in the Baltic Sea, usually caused by blue-green algae.
"Dead zones" lack enough oxygen to support marine lifeThey are caused by agricultural waste and sewage flowing into seaSweden trialling plan to pump oxygen into Baltic Sea -- world's largest dead zone Critics say it's a distraction from the need to reduce pollution. Teenager gives world leaders her vision for the future. Brittany Trilford will address world leaders at the Rio + 20 summit.
Brittany Trilford, 17, will address world leaders at the Rio + 20 summit next week"I envision a future where every person's rights are respected and protected," she saysShe believes that schools should encourage creativity and collaborationWe should take inspiration from nature and learn to re-use waste, says Trilford Editor's note: Brittany Trilford is a 17-year-old New Zealander. She recently won the Date With History competition and will address world leaders at the Rio + 20 Earth Summit next week. Wellington, New Zealand (CNN) -- In April this year I read an email newsletter from a youth leadership forum in my hometown of Wellington, New Zealand, that I regularly receive. I immediately started writing ideas on my hand during school. Since hearing that I'd won the contest and will really speak truth to power, I've been thinking long and hard about the future I want. Date With History: Youth want green future.
On the front line of climate change: Five cities battling floods, heat and storms. Climate change has the potential to cause unprecedented damage to urban areas -- both in terms of human life and financial capital.
What will cities do to cope with rising sea levels, heatwaves, droughts and more frequent and severe storms? How will they protect their populations and economies? Cities are, in fact, uniquely placed to answer these questions. City mayors are often more able than nationally elected politicians to take decisive action on environmental initiatives, making many cities pioneers in adapting to climate change. CNN has teamed up with The C40 Cities Climate Leadership Group and the Carbon Disclosure Project to show the risks climate change poses to five major global cities and the steps they are taking to protect them for future generations. Olympic Park sets gold standard for sustainability.
London 2012 organizers have transformed a neglected area of the East End into a green and sustainable Olympic Park.
After winning the bid to host the Games back in 2005, work began on clearing the brownfield site full of derelict land and dilapidated buildings -- more than 200 were demolished to make way for the Olympic Park, say organizers. The venues, like the velodrome pictured here in the background, blend into the landscaped parkland creating a number of striking vistas. More than 4,000 trees, 74,000 plants and 300,000 wetland plants have been used on 500-acre site.
Ecosistemas. Will elephants still roam earth in 20 years? According to Christo, at the beginning of the 1980s there were over a million elephants roaming Africa.
Today that number has dramatically fallen to "no more than 400,000. " Elephant figures are dramatically decreasing due to poaching and black market ivory tradeChristo says in 10 years time, if slaughter continues most of Africa's elephants will be goneThe world faces losing the "linchpin of ecology of an entire continent" Americans' 'amazing' feats against storm and heat. Fatima Domingpe applies sunscreen to her face near the Mosaic Fountain in downtown Silver Spring, Maryland, on Saturday, July 7.
