This Earth Day, the United States, China, and Canada are among more than 170 countries expected to take part in the largest one-day signing of an international agreement in history. The ratification of the climate agreement hammered out at the Paris Conference of Parties (COP-21) last December could be the most significant elevation of environmental issues on the global stage yet.

This Earth Day weekend, the U.S. Department of State is hosting more than 2,000 coders in more than 40 cities to encourage creative thinking about technological solutions to ocean issues. The third annual Fishackathon could produce new tools for local communities to track long-distance fishing, a growing problem in some places, as China, in particular, scales up its efforts.

Blackened rivers snake the ring roads of Beijing, carrying pollution and often smelly water from one end of the city to another. The most polluted of these have been dubbed “foul and filthy” rivers (黑臭河) by China’s Ministry of the Environment (MEP) and Ministry of Housing and Urban-Rural Development (MOHURD). However, the government has decided to clean these up – and is enlisting the help of the public to do so.

According to political demographers, who study the relationship between population dynamics and politics, two characteristics when observed together provide a rather good indication that a state is about to shed its authoritarian regime, rise to a high level of democracy, and stay there. Myanmar has both.

The climate agreement reached in Paris last December, seen by many as a critical step toward lowering greenhouse gas emissions, was big news – perhaps too big. Pointing to the thousands of articles about COP-21, National Geographic Senior Editor Marla Cone asked at a recent Wilson Center panel, “Is this a wise use of resources, when newsrooms are so stretched thin, to have everybody pretty much chasing the same stories?”

In a study published in Science Advances, Mesfin M. Mekonnen and Arjen Y. Hoekstra estimate that over 4 billion people, approximately two-thirds of the world’s population, face severe water scarcity for at least one month out of the year – far greater than previous estimates of between 1.7 billion and 3.1 billion. The authors examined global water scarcity data from 1996 to 2005 on a monthly basis and at a more localized resolution to show how water scarcity affects different places at different times of year.

China’s “strictest air protection law” yet took effect on January 1, 2016, promising to bring big changes to its smog-filled cities. But some municipal governments have been ahead of the curve, working to clean up the air through experimentation and innovation. Shenzhen, China’s first special economic zone and which recently passed its neighbor Hong Kong to lead China’s most competitive cities, is one of these.