United Nations (CNN) -- On Tuesday, it was climate change. Wednesday, terrorists. And on Thursday, President Barack Obama confronted yet another emergency that threatens wide destruction overseas: the Ebola outbreak spreading in West Africa. Crisis management has become a hallmark of Obama's second term, perhaps seen nowhere better than at the annual United Nations General Assembly, where the world's leaders -- and their attendant calamities -- converge upon New York. Obama's three main issues here -- climate change, ISIS and Ebola -- each has the potential to rapidly spiral out of control, officials suggest, with the effects of a warming planet already being registered and Americans overseas already being killed both by terrorists with the Islamic State in Iraq and Syria and by the deadly virus spreading in Africa.
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Obama made clear at the U.N. that the U.S. isn't going to take the world's problems alone
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Obama's main issues at U.N. -- ISIS, climate change, Ebola -- could spiral out of control
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"Resolutions alone will not be enough. Promises on paper cannot keep us safe."
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That warning of the limits to U.S. power is broadly the same message Obama wanted to deliver on climate change and @placeholder, which he focused on this week.
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Both threats, Obama said at various points, will require coalitions of governments to act rather than the @placeholder alone.
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"This is not @placeholder's fight alone," he said Tuesday before leaving for the global gathering in New York.