Hence the frustratingly immutable truth of climatology: It is impossible to tie individual events to climate change. Further complicating matters is that climate itself is astonishly complex, and drought is an ideal example. Yes, heat from global warming can be a contributing factor—heat increases evaporation which, in turn, dries out the land. But a drought’s defining feature is lack of rain, not necessarily rising heat. In fact, droughts have been known to occur during cold periods. Added to that, rain and heat are hardly the only factors that need to be considered. Land use (whether a region has more farms or forests or cities or suburbs), ocean currents, El Niño events, or as Sloan’s model showed, melting Arctic sea ice, can all conspire to worsen or alleviate any given drought.