The mysterious X factor behind a year of unbelievable heat

Predicting the future has always been a difficult, sometimes fruitless task, but scientists are surprisingly good at divining how hot the year ahead will be. For decades, their models have largely ended up matching global temperatures. Then 2023 came along. At the beginning of the year, climate scientists at four organizations — Berkeley Earth, NASA, the U.K. Met Office, and Carbon Brief — forecasted that 2023 would be marginally hotter than the year before, with the consensus falling around 1.2 degrees Celsius of warming (2.2 degrees Fahrenheit) above preindustrial temperatures....