Many people die of cold and many die of heat each year. If you raise the temperature, the extra heat both reduces cold deaths and increases heat deaths. Lowering temperature (or preventing its rise) would also both prevent and cause deaths. If, as statistics seem to indicate, there are far more cold deaths than heat deaths, the extra heat is more likely to produce a net saving of lives, not a net loss. But even if not, any article that uses extra heat deaths as an argument without so much as mentioning concomitant prevention of cold deaths is not reliable if your goal is to save lives.