South Korea has almost zero food waste. Here's what the US can learn

Phone lines in Africa and South Asia would never have gotten to the poor - but these places have leapfrogged over last-century technology and gone straight to mobile phones. Now the same thing is happening with off-grid solar power: the fastest -- perhaps the only – way to power the poor.

Nationally, only about a third of municipal solid waste is recycled. An initiative to use simpler, standardized signs and labels is helping communities reap greater benefits from recycling.

In light of climate change, New York State's Common Retirement Fund, the country's third-largest pension fund, decided to invest in a way that rewards companies with low carbon footprints.

Most people are unaware of how much food they waste. Food waste campaigns across the world are using creative marketing to raise awareness and encourage behavior change.

Lack of access to sanitary bathrooms in the village of Kivalina, Alaska led to the implementation of a novel, home-based water sanitation system, currently being tested for effectiveness. The hope is that it proves to be a solution for areas all over the state with lack of access to clean water systems.

Throughout India, wastepickers – people who scour landfills for garbage they can sell to recyclers – live at the bottom of society. But the city of Pune did something radical: with the help of a collective, they did away with expensive garbage trucks, and now all household garbage is collected by wastepickers with pushcarts. Pune saves millions of dollars each year and recycles more – and the wastepickers have decent wages and social standing. The concept is now spreading globally.

To decrease the nation's food waste, activists in Denmark showed the people that it was safe to buy and consume items that were very recently expired. From live demonstrations where celebrity chef features expired items in the entrees to reducing prices for out-of-date items, "Danes now throw away 25 percent less food than they did five years ago."

Crop production is very high in Tanzania but the farmers have no way of storing crops so most produce goes bad. Researchers are beginning to create storage systems that allow for produce to last longer and help farmers create a greater product and income.

One program has found a way to turn feces into agricultural compost, which has helped Haiti, a country with limited sanitation systems, both keep its water clean and grow food.

The amount of plastic debris in our oceans and water sources - especially nanoplastics that are increasingly prevalent in our food chain - is so enormous it's often beyond comprehension, and immensely difficult to address. As countries continue to industrialize and single-use products become more commonplace, the flow of harmful plastics into the environment seems insurmountable. But a number of clever inventions and dedicated individuals are working to help get plastics out of our water - and more importantly - encourage practices to reduce, reuse, and recycle.