It's easy to become discouraged when considering the state of our planet. We're constantly bombarded with stories about how our cities are collecting in smog, our ice caps are melting and our temperatures are skyrocketing (I mean, who in the Northeast wasn't freaked out by the great Christmas Heatwave of 2015).

Climate change presents a complex challenge, but it's one we can all approach with a healthy dose of optimism. The environmental movement reached some seriously impressive milestones in 2015 — here are a few I was especially grateful to see as mbg's green editor.

1. Wellness companies found some pretty ingenious ways to upcycle materials

In an effort to cut down on waste, manufacturers continued to design upcycled goods from used material this year. This yoga mat constructed out of recycled wetsuits and these Adidas sneakers made with ocean plastic trash are just a few examples of trendy, practical second-life products that any wellness junkie could use.

Read up on how you can upcycle materials in your own home here.

2. Billions of dollars were invested in clean energy research

Thanks in large part to donations like Bill Gates' recent multi-billion dollar fund, alternative energy sources are becoming less expensive and more widely available. In a shift away from coal, the U.S. now sources about 13% of its energy from renewable resources. At one point this summer, Denmark wind farms collected enough power to fuel the entire country and then some.

3. The world came together at the Paris Climate Summit

Earlier this month, 195 government leaders from across the world met in Paris to draft a comprehensive plan to combat human-caused climate change. The resulting Paris Agreement calls on every country to do its part in reducing greenhouse gas emissions and holding global temperature rise below 2 degrees Celsius. The accord is the first of its kind, and President Obama said it "represents the best chance we have to save the one planet that we’ve got."

Read more about the historic climate agreement here.

The Eiffel Tower donned a makeover for the climate talks
Photo credit: Getty Images

4. We started to tackle the trashy problem in our oceans

The bad news is that there's a ton of plastic in our oceans — anywhere between 93,000 and 236,000 metric tons, according to a recent study. Upwards of 13,000 pieces of plastic are dumped into our waterways each day, and they often end up in massive garbage patches or, worse yet, in the bellies of wildlife. But there's some (relatively) good news too. The U.S. government just passed a bill demanding that personal care companies rid their products of microbeads — tiny plastic particles that collect in waterways and can be dangerous to marine life. Meanwhile, innovators like 20-year-old Boyan Slat are thinking up creative ways to clean up existing marine debris. Slat will test his design for a floating ocean boom that uses ocean currents to collect trash off the coast of Japan in 2016.

To learn more about how you can cut down on your plastic use, read about this woman's awesome plastic-free journey.

5. Major clothing brands vowed to clean up their production practices

The fashion industry is a notoriously unsustainable one. Up to 2,000 gallons of water go into producing a single cotton T-shirt and an estimated 20% of industrial water pollution comes from textile dying. In an effort to get these figures down, traditionally "fast fashion" corporations like Kohl's, Nike, Target and Walmart signed onto the American Business Act On Climate Pledge this year. Some promised to reduce their water consumption while others pledged to invest in more renewable energy sources, but each company set a specific plan to lessen their environmental impact in some way.

Shoppers can now check in on their favorite brands with resources like projectjust.com — a site that compiles information on the transparency, labor conditions and business models of popular retailers.

6. Large restaurant chains made green pledges

Likely fueled in part by the impassioned campaigns of celebrity chefs like Tom Colicchio and Dan Barber, 2015 proved a promising year for sustainable restaurant reform: Chipotle nixed its genetically modified foods, Taco Bell opted to serve cage-free eggs in its breakfast options, and Kraft, Nestlé, Panera and Subway promised to get rid of their artificial ingredients. Sweet Green introduced a salad made out of food scraps and Starbucks announced that it has more LEED certified locations than any other global retailer. All these changes speak to an underlying dining shift towards natural, healthy fare served in sustainable spaces.

7. Farming saw a resurgence

In a movement largely spearheaded by health-conscious millennials, more people than ever before are shopping for local, organic food. The head chef behind NoMa, the Copenhagen eatery voted the Best Restaurant in the World last year, recently announced plans to close doors and reopen atop an organic urban farm in 2017. The farm-to-fork movement is clearly having a moment — time to dig in.

The rooftop farm atop Bell Brook & Candle in Manhattan
Photo courtesy of the author

8. The tiny home movement got big

Tiny homes are less resource-intensive to build and less energy-exhaustive to maintain than traditional houses, plus they often give their owners more freedom and mobility. These days there are plenty of design options for people looking to take a walk on the minimalist side, and you can find everything from tiny wooded retreats to wind-powered pods.

Think you have what it takes to live tiny? Check out some of the most incredible tiny home models here.

9. Bikes took over city streets

Hopping on alternative transportation is a great way to cut down on one's carbon footprint, for cars are one of the most egregious contributors to dangerous air pollution. Many European cities are encouraging residents to add some green to their daily routines by making streets more bike-friendly. Earlier this year, Paris held its first carless day — a city-wide event that reduced smog-producing chemicals by 40 percent — and Oslo announced that it will completely ban cars from its city center by 2019. Milan is currently in the midst of a three-day car ban of its own, and Dublin and Madrid aren't far behind.

Main Photo Credit: Getty Images