LONDON - Wealthy nations must fight climate change on security grounds, as they will have to deal with any mass movement of people displaced by the effects of global warming, Nobel Prize laureate Wangari Maathai said on Friday.

Maathai, who won the 2004 Peace Prize for her work on sustainable development, called on negotiators at U.N. climate talks starting next week to agree an amount of climate change financing for poorer countries that will make a difference.

It is not only a moral obligation but it is also really an issue of security. You can imagine what is going to happen in many places where we may have massive migration of people and they will definitely have to be dealt with, especially by the developed world, she told Reuters Insider television.

So I hope that countries like America will look at it not only as a climate issue, a moral issue but also as a security issue, said Maathai, a Kenyan.

According to frequently cited estimates, between 200 million and 1 billion people could be forced to leave their homes by 2050 because of global warming, a London-based think thank noted in a report earlier this year.

Rich countries agree they should help poorer ones combat climate change, which will affect developing nations the most while they contributed the least to the problem.

How much money to give will be one of the main sticking points on a global warming deal at the 190-nation climate conference in Copenhagen.

Countries that receive such money must use it with transparency and accountability, said Maathai.

It is important ... to make sure that the resources are actually used to make the difference because whatever happens, it is not only important for the regions that benefit financially but the whole world, she said.

A United Nations report said in September that climate change was altering weather patterns, so natural disasters were an extremely important driver of forced displacement globally.

If displaced people seek refuge abroad, they would not have any rights in host countries. Existing international laws protect only cross-border refugees who are forced to migrate due to violence or political, racial or religious persecution.

Experts disagree over whether people uprooted by climate change are likely to move locally or beyond the borders of their countries.

But some small island states see little choice. For example, the Pacific island nation of Kiribati has asked larger nations, including New Zealand and Australia, to open their doors to its citizens who might become climate refugees.

(Writing by Olesya Dmitracova, Editing by David Stamp)

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