A new PLoS ONE study shows that to avoid extinction, small populations may need fertility rates well above the standard ...

Forget what you know about the replacement rate—new research suggests the world needs more children than previously thought ...

Fertility rates are falling across the world. This isn’t just a social concern—it’s a mathematical warning. In places where ...

In his new book "Hope Dies Last," award-winning environmental journalist Alan Weisman shares the four existential threats ...

Increasing urban vegetation by 30% could have saved more than one-third of all heat-related deaths, saving up to 1.16 million ...

The U.N.'s Sustainable Development Goals (SDGs) track more than 230 performance indicators to determine progress in social, ...