evidence: Temperature records have been shattering left and right as searing, unrelenting heat has enveloped numerous spots around the planet—from Phoenix, Ariz., to Sanbao, China, where it is summer, to southern South America, where it is winter. Breaking high-temperature records is a hallmark of climate change. With more and more heat being trapped in the atmosphere by the greenhouse gases emitted when humans burn fossil fuels, heat records are now set increasingly more often than cold ones. [...] Climate change leads to longer, stronger and more frequent heat waves. A recent study from the World Weather Attribution group found that some of this summer’s record-setting heat waves would have been "virtually impossible" without climate change. A hot summer of the past is an average one today, and the current hot summers will be considered pretty average in the future.