• Mexico;
  • climate change;
  • drought

Prolonged drought conditions have persisted over western North America since at least 1999, affecting snowpack, stream discharge, reservoir levels, and wildfire activity [Mote et al., 2005; Westerling et al., 2006; MacDonald et al., 2008]. Instrumental precipitation, temperature, and Palmer Drought Severity Indices (PDSI) indicate that severe and sustained drought began in 1994 in Mexico, where it has continued with only limited relief for the past 15 years. This late twentieth-and early 21st-century Mexican drought (referred to below as the [early 21st-century drought]) has equaled some aspects of the 1950s drought, which is the most severe drought evident in the instrumental climate record for Mexico (1900–2008). Large-scale changes in ocean-atmospheric circulation have contributed to the lower than normal precipitation that has led to the current drought [Seager, 2007], but global warming and the sharp regional warming across Mexico, which appears to have been aggravated by land cover changes [Englehart and Douglas, 2005], may have added an anthropogenic component to the early 21st-century drought.