Every morning, 15-year-old Lorna wades into the Kemp Welch river in Launkalana, Papua New Guinea, and swims to the other side — past crocodiles, past submerged debris, past the place where a footbridge once stood. That bridge was destroyed by heavy rains in 2012 and has never been replaced. Hundreds of children make the same crossing each day, though during menstruation the community's elders forbid girls from entering the water, fearing the scent will draw crocodiles. "My dream is to become a teacher or pilot," Lorna has said.

"We want a new bridge so we can go to school safely every day." Her story is not exceptional. According to a new report from Unicef, more than one billion children worldwide are now simultaneously exposed to at least three distinct climate hazards — heatwaves, storms, floods or droughts — at the same time. The Children's Climate Risk Report, released this week, also found that virtually every child on the planet faces at least one such threat, regardless of whether they live in a low-income country in the Pacific or a wealthy city in Europe.

At the extreme end, roughly 123,000 children are estimated to experience more than six overlapping hazards across their lifetimes. The report documents how rising temperatures and increasingly erratic weather are placing mounting pressure on critical infrastructure.