As the demographer Glenn Firebaugh carefully shows, income inequality for the world peaked in the late twentieth century and is now heading downward because of declining income inequality across nations. Furthermore, as income inequality declines across nations, it is rising within nations (though not as rapidly as it is declining across nations).

Critics of globalization and others maintain that the spread of consumer capitalism is dramatically polarizing the worldwide distribution of income. But as the demographer Glenn Firebaugh carefully shows, income inequality for the world peaked in the late twentieth century and is now heading downward because of declining income inequality across nations. Furthermore, as income inequality declines across nations, it is rising within nations (though not as rapidly as it is declining across nations).