It's five weeks until the U.S. presidential election and more than 7,000 miles away, one activist has a request: Vanessa Nakate wants American voters to consider the impact of their ballot on the climate.

Nakate founded a climate education movement last year and has more than 175,000 Twitter followers.

Her mission was given a new urgency by heavy floods that have displaced more than a million people across South Sudan, Sudan, Ethiopia and parts of Uganda - a region heavily dependent on agriculture.