A University of Arizona researcher says the vulnerable Horn of Africa will likely become drier from climate change.

Jessica Tierney reconstructed 2,000 years of climate history in eastern Africa to try to place recent drying in context. A geoscientist, Tierney used sediment cores and other archives in her study.

"It looks like in the 20th century, the Horn of Africa has been getting drier and that seems to be related to the rise in greenhouse gases. And the longer paleoclimate context for that is, generally speaking, when it’s warm in the Horn of Africa, it tends to be drier and when it’s cool, it’s wetter," said Tierney. "We see that relationship hold for the last 2,000 years."

Tierney said this region depends on rainfall to irrigate crops, so reduced rain can impact food production. A severe drought in 2011 resulted in a worldwide humanitarian aid effort to provide food for 13 million people affected by famine.