Conclusions
•• Spring and summer rains in parts of Ethiopia have declined by 15–20 percent since the mid-1970s.
•• Substantial warming across the entire country has exacerbated the dryness.
•• An important pattern of observed existing rainfall declines coincides with heavily populated areas of the Rift Valley in south-central Ethiopia, and is likely already adversely affecting crop yields and pasture conditions.
•• Rapid population growth and the expansion of farming and pastoralism under a drier, warmer climate regime could dramatically increase the number of at-risk people in Ethiopia during the next 20 years.
•• Many areas of Ethiopia will maintain moist climate conditions, and agricultural development in these areas could help offset rainfall declines and reduced production in other areas.