In Genoa, Italy, Bush is expected to tackle missile defense, global warming, global economic problems and other issues.

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The Nature article, also published Thursday, said that such shifts in weather patterns and human-induced changes could have sudden and unpredictable effects on the global ecosystem, including the collapse of food supplies and other problems.

CNN: STORY HIGHLIGHTS

This was because he urged global cooperation to combat nuclear proliferation, climate change and other problems that go beyond the borders of any one country.

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That the world's policymakers need to pay more attention to global warming, AIDS orphans, endocrine disruptors, nuclear proliferation and other very important problems.

CNN: ASIANOW - TIME Asia | Davos 2000: So Long, Farewell