Indian Ocean version of El Niño behind drought in East Africa

https://www.newscientist.com/article/mg23331174-200-indian-ocean-version-of-el-nio-behind-drought-in-east-africa/

Mar. 15, 2017

AN INDIAN Ocean phenomenon is partly to blame for the severe drought in East Africa, affecting maize and sorghum harvests and sending food prices soaring. A famine has been declared in South Sudan, while Kenya and Somalia have announced national emergencies.

According to the UN Environment Programme, 17 million people in the region now face hunger. “We are currently facing potentially the worst humanitarian disaster the world has known since 1945,” says Mike Noyes at the charity ActionAid.

Long-term weather forecasts suggest it won’t rain for several months. The drought is partly caused by the Indian Ocean dipole, which is similar to El Niño in the Pacific: sea surface temperatures in the east of the ocean cycle between cold and warm relative to the western ocean.

.

The dipole was particularly strong in 2016, with warm temperatures in the east creating more moisture in the atmosphere. This cools the air in the east, leading to winds blowing eastward from Africa across the ocean. They push away the moist air that normally brings rain to East Africa from October to December.

The famine is the third to hit the region in 25 years. The last, in 2011, resulted in 260,000 deaths.

The dipole has been getting more pronounced in recent