Milena Glimbovski, Germany

The average German produces 250 kilograms (550 pounds) of waste every year. And if you go grocery shopping at a normal German supermarket, you'll quickly see why: From meat to cheese, vegetables to fruit, most items on sale are wrapped in plastic. That’s something 25-year-old Milena Glimbovski couldn't wrap her head around.

"Why is all of this food I buy every day wrapped in so much plastic? Is that really necessary?" Milena says. "I mean, it's crazy: you can even buy ecologically friendly condoms, but you can't get food without packaging," she adds.

So she decided to set up Berlin's first packaging-free supermarket. That was not a piece of cake: For example, finding suppliers who deliver food without packaging took her a whole six months.

What started as just an idea in 2012 finally became a reality in September 2014. Since then, Milena has been the proud owner of a small shop, aptly called "Original Unverpackt" (Original Unpackaged).

It is located in Berlin's vibrant, trendy Kreuzberg district, and sells 400 different products - from nuts to noodles - all package-free. Customers can fill as much of each product as they want into small linen bags, Tupperware they bring from home, or glass jars they can get in Milena's shop. As long as it's reusable.

What does that have to do with the climate?

Milena is doing the climate a big favor: In order to produce plastic wrapping, it takes fossil fuels like oil, gas and coal. About four percent of the world's annual petroleum production is converted directly into making plastics, and another four percent gets burned to fuel the process. To produce one kilogram of plastic, six kilograms of carbon dioxide are emitted - that's about as much as a 40-kilometer-long car ride emits. This obviously doesn't do the climate any good.

Milena's customers love not only the products, but also the shopping experience itself: Turns out that shuffling nuts into bags brought from home is actually way more fun than just tossing a pre-packaged bag of nuts into a cart.

But when they get to the spaghetti section, many customers are a bit helpless, Milena says. "They wonder: where could we possibly put that?" Spaghetti won't fit in most Tupperware containers.

But Milena is used to solving problems, so she even has an answer to this: "Old Pringles tubes," she says and smiles. Genius.