Zambia is wrestling with a devastating drought caused, according to experts, by a dramatic shift in weather patterns.

Temperatures in parts of Southern Africa are expected to rise by twice the global average as a result of climate change, and the UN is calling for urgent action.

In Zambia, more than 2m people are now in need of food aid, following two years of poor rains and failed harvests.

The BBC's Africa Correspondent Andrew Harding reports.