New Delhi, Dec. 22 -- When Dickson Ngome first leased his farm at Lake Naivasha in Kenya's Rift Valley in 2008, it was over 2 kilometers (1.2 miles) from shore. The farm was on 1.5 acres (0.6 hectares) of fertile land where he grew vegetables to sell at local markets.

At the time, the lake was receding and people were worried that it might dry up altogether. But since 2011, the shore has crept ever closer. The rains started early this year, in September, and didn't let up for months.

One morning in late October, Ngome and his family woke up to find their home and farm inside the lake. The lake levels had risen overnight and about a foot of water covered everything.

"It seemed as if the lake was far from our homes," Ngome's wife, Rose W...