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.

Today, Africa has the world’s highest fertility rates. On average, women in sub-Saharan Africa have about five children over their reproductive lifetime, compared to a global average of 2.5 children. Research shows that the “demographic transition,” the name for the change from high death and fertility rates to lower death and eventually lower fertility rates, has proceeded differently here from other regions in the developing world.

Iraq has seen its share of calamities in recent years, but none is as dangerous as the impending failure of the Mosul Dam. A breach of the dam will result in a tsunami-like wave that sweeps through cities and hamlets along the Tigris River from Mosul to as far south as Amarah and even Basra. Baghdad would be submerged under five meters of water within four days. Not only do experts estimate the possible fatalities to range from 500,000 to more than 1 million, but consider the logistics of trying to provide electricity, drinking water, food, hospitals, transportation, and diesel for millions of people.

Last month, the World Bank’s Fragility Forum in Washington, DC, brought together some 600 participants to discuss how to advance sustainable development in the context of increasing conflicts and violence. World Bank President Jim Yong Kim opened the forum by emphasizing that we are at a critical moment.

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.

Though governments have agreed to try to limit global warming to no more than two degrees Celsius above pre-industrial levels, a paper by James Hansen et al. in Atmospheric Chemistry and Physics finds that goal may not prevent major changes on an irreversible and unadaptable scale. Studying the last interglacial period, about 120,000 years ago, when the temperature was less than one degree Celsius warmer than today, Hansen et al. estimate sea level was six to nine meters higher than today.