In 1997, countries around the globe debated whether or not to sign the Kyoto Protocol, an international treaty to limit greenhouse gas emissions from human activities. The idea that humans were altering the global climate was still very new — but now, a handful of citizen scientists had uncovered evidence that suggested something even more unsettling: the change wasn’t just coming. It had already begun. Four months before countries had to decide, scientists at the British Trust for Ornith...
