Prior to global awareness of coal mining's role in climate change, experts projected that coal would be responsible for one-third of the world’s energy supplies by 2050. Now that climate change is a common household phrase, more and more governments, companies and citizens' groups are calling for renewable energy sources to replace coal.

This collective agenda was abundantly clear at the recent United Nations Global Climate Summit in Bonn, Germany, which ended last week.

In Bonn, many countries exhibited their deep commitment to ending coal's carbon emissions as early as 2030. But, of course, there are still advanced industrial nations — namely Germany and the U.S. dragging their heels as others adopt concrete coal-cutting measures.

As one of the dirtiest fossil fuels, coal is said to kill just under a million people per year due to air pollution alone. The U.S. led the pollution charge until China topped it in 2006. China is notorious for the role coal mining plays in mass pollution.

Coal is responsible for aiding China's economic rise over the past few decades, but now China suffers greatly from its burning of 6 million tons of coal a day. The result of this level of burning is that China is double the hazardous standard for air pollution recognized by the U.S. Environmental Protection Agency.

Of particular concern here is the presence of large and "ultrafine particulates," which can include black carbon, sulfates and nitrates. When breathed in, these particulates have major respiratory effects resulting in a public health crisis that has many fleeing larger cities, like Beijing, for cleaner air.

In India, another powerhouse polluter, coal mining is on the rise and shows no sign of stopping. In fact, while China has shown interest in reducing coal production as part of a global effort to reduce greenhouse gasses, India's power minister aims to "double India's use of domestic coal from 565 million tons last year to more than a billion tons by 2019."

India's cities rival with China's for pollution, with Delhi's air roughly three times as toxic as Beijing's. If we consider projections that up to 37 million Indians could eventually be displaced by rising sea levels, it is significant that India continues its dirty, high-ash-content coal production in the face of this imminent threat.

Residents of Beijing routinely wear masks outside to prevent inhaling the polluted air.

Enter the recent Bonn UN climate summit amid this international coal burning crisis. The good news is that 20 countries pledged to quickly phase out coal, with the UK leading the pack by pledging to end coal use by 2025. Other countries in the alliance include Angola, Austria, Belgium, Canada, Costa Rica, El Salvador, Fiji, Finland, France, Italy, Luxembourg, Marshall Islands, Mexico, Netherlands, New Zealand, Niue, Portugal and Switzerland.

While this list of committed countries is a hopeful start, it is significant that the world's top three coal producers China, India and the United States did not join this new alliance. In fact, the Trump administration actually promoted "clean" coal production at the climate talks, but alternative U.S.-based voices were also present.

Former New York City mayor Michael Bloomberg, who attended the Bonn talks, has launched a $164 million initiative to replace coal with renewable energy sources in the U.S. This has resulted in 50 percent of coal plants shutdown in the past six years: 94 U.S. coal-fire plants were closed in 2015. Europe is his next target, as he recently pledged $50 million for this project, and Asia is next on his list.

While all of this is good news, a key question remains. How much good is an anti-coal global alliance without formal endorsements from the world's top three coal producers? The independent success of Bloomberg's campaign tells us that money-backed citizens can lead the drive against coal, regardless of governments' intentions.

In Germany, the Hambach coal mine is Europe's largest open-pit coal mine at 85 square kilometers and around 370 meters deep. It is responsible for producing the much-less-efficient dirty, brown coal. For the past five years, activists have targeted the mine's expansion as the surrounding forest is now reduced to 10 percent of its original capacity.

As one of the single sources of Europe's carbon emissions, the mine is on the frontlines of the anti-coal battle. On Nov. 5, several thousand activists occupied the mine — Some have built treehouses nearby to defend the forest. So, while we hear news of Germany's inability to reach emissions cuts by 2020, due to continued reliance on coal, we also see many German citizens taking their country in a different, more urgent, direction.

This ongoing campaign is one of 70 global "Blockadia" campaigns that use direct action with local community involvement to challenge coal production and fossil fuel extraction. Strange bedfellows indeed, but grassroots organizing efforts coupled with big money, Bloomberg-style, might pressure the largest coal producers yet.

Time is borrowed here, as we continue to witness the struggle between coal producers and a global majority that says "enough is enough" when it comes to burning coal.