One simple target has guided climate-treaty discussions for decades: Keep the rise in average global air temperatures below two degrees Celsius. But is it the right number? WSJ's Niki Blasina explains the two-degree model—and why scientists are now at odds over it. Photo: AP.
Protests in Chicago are ongoing as the investigation into police officer Jason Van Dyke's fatal shooting of 17-year-old Laquan McDonald continues.
Shortly after arriving in Paris, U.S. President Barack Obama visits the memorial at the Bataclan concert hall to pay tribute to the victims of the deadly Paris attacks. Rough Cut (no reporter narration).
A combination of system malfunctions and improper pilot responses to electrical and rudder-system problems led AirAsia Flight 8501 to crash in December last year, killing all 162 people on board, Indonesian investigators found. Photo: Getty Images
Scientists have identified a Grandparent Gene that may protect the elderly from dementia and Alzheimer's. TC Newman (@PurpleTCNewman) has details.