This year was a big one for the planet, and world leaders are finally listening to scientists who say all is not well in the world.
But while some things look dire, we've made progress in 2015. The planet has banded together to stave off the worst effects of climate change. Threatened habitats have been protected, and most of us cite environmental protection as one of the biggest issues of our time.
While there's still work to do, here are five things that would've made Captain Planet proud this year. Let's hope the Republican presidential candidates take note.
The world approved a landmark climate deal
After more than a decade of misfires, the world finally reached a sweeping climate deal in an effort to halt the worst of greenhouse gas-induced warming. The leaders of more than a hundred nations were present in Paris for the landmark talks, which United Nations Secretary-General Ban Ki-moon called "a historic moment ... [for] one of the most crucial problems on earth."
The pact itself will encourage nations, especially the biggest carbon emitters like the U.S., China and India, to move away from fossil fuels and invest in renewable energy. By itself, it won't keep the planet from crossing the warming threshold scientists say we must stay beneath to avoid the worst climate-related effects. But the deal represents what President Barack Obama called "the best chance we have to save the one planet that we've got."
Obama established the planet's biggest marine sanctuary
In September, Obama created the world's largest protected marine reserve in the Pacific Ocean. The act expanded the Pacific Remote Islands National Marine Monument to nearly half a million square miles.
The move represented a significant shift in environmental policy in the U.S., where more than 10 percent of land is protected, but less than 1 percent of the ocean is.
Most of us care about climate change (except Americans)
Most of the world now realizes climate change is one of the most trying problems of our age. A full 54 percent of nations identify the issue as a "very serious problem," according to a recent poll by the Pew Research Center, while 85 percent say it's at least a "somewhat" serious issue.
Unfortunately, that concern doesn't spread to America, one of last bastions of climate denialism worldwide. The U.S. is largely unconcerned with the issue despite near-universal calls for action from the planet's leading scientists, and more than one in three people said they were either not too worried or not worried at all about the issue.
Renewable energy fueled more than ever
Several major renewable energy milestones were set in 2015 as cities and entire countries announced plans to fuel their entire grids with clean power.
Germany set a new national record as a full 78 percent of the country's power was met through renewable sources during one day in July. The governor of New York announced the city's intentions to fuel half of all power in America's largest metropolis with clean energy, and San Diego said it would be entirely renewable in just 20 years.
The largest polluter announced a cap-and-trade program
During Chinese president Xi Jinping's visit to the United States, the leader of the world's biggest carbon emitter announced China would launch a national emissions trading program in 2017.
For years, Republicans had pointed to China's lack of action on climate change -- namely, because of fears it would squelch business -- as a prime reason why the U.S. should be hesitant to take action too. Xi's announcement came just ahead of the Paris climate talks and represented a massive, focused commitment to tackle the issue by a nation as reliant on coal as America is on oil.
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