Russia’s moves to mobilize thousands more troops and to annex more of Ukraine’s territory signal a new, potentially more dangerous phase of the war.

Amid renewed calls for changes in the world order, U.S. President Joe Biden sought to stress his support for greater inclusion of developing nations in addressing economic, social, and climate concer…

Climate change is fueling geopolitical competition in the Arctic. An independent Greenland could play an important role in years to come.

Scientists say the rain forest is approaching a critical tipping point at which the damage is irreversible.

The main battle tanks that the United States and Germany have agreed to provide Ukraine will help its forces punch through Russian fortifications and retake lost territory.