* Poor cities must do more to cope with climate change-U.N.
* African slums swollen by environmental refugees
By Alister Doyle, Environment Correspondent
OSLO, March 17 (Reuters) - Cities in developing nations must do far more to cope with global warming that is already swelling the slums of Africa with environmental refugees, the head of the U.N. housing agency said on Tuesday.
Urban areas, home to just over half the world's population, are key to tackling global warming because they account directly for 50-60 percent of human greenhouse gas emissions, according to Anna Tibaijuka, executive director of U.N. Habitat.
"How we plan, manage and live in our expanding cities determines, to a large extent, the pace of global warming," she told a conference in Oslo to launch a U.N. initiative to help cities in developing nations confront climate change.
She said that towns and cities, especially fast-growing urban areas in many poor nations in Africa and Asia, had largely overlooked work to redesign infrastructure to cope with threats such as rising sea levels, floods or droughts.
They also need less polluting transport systems and should design buildings that use less energy. "It's not only planting trees and leaving it at that," she told Reuters, referring to inadequate urban planning.
"The most affected today, and in future, will be the world's urban poor -- and chief among them, the estimated one billion slum dwellers," she said in her speech. "For them, the climate is already out of control."
"In the the slums of Africa, about one in three slum dwellers can be considered as an environmental refugee, driven off the land by advancing desert frontiers and failing farming systems," she said.
The meeting launched pilot projects to help Maputo in Mozambique, Kampala in Uganda, Sorsogon City in the Philippines and Esmeraldas in Ecuador to adapt to climate change.
"People say typhoons and storm surges in the past decades have become more destructive," said Leovic Dioneda, mayor of Sorsogon, a coastal city of 150,000 people. Measures included replanting mangroves to protect the coastline from erosion.
"Investment in drainage, in infrastructure, will be crucial," said Florence Namayanja, deputy mayor of Kampala. But she said that Uganda would need "colossal amounts of money" to cope.
-- For Reuters latest environment blogs click on: blogs.reuters.com/environment/ (Editing by Richard Balmforth)