Thanks to rapid growth rates, especially in China, global inequality has actually decreased over the last few years. At the same time, however, within-county inequality has also increased a lot. This phenomenon is especially pronounced in the Anglo-Saxon economies where the top income shares are taking on an increasing share of the pie. We see a similar trend across all advanced economies as well as developing countries like China (see the world wealth and income database for the fantastic data, link below).
While from a global welfare point of view we should care much more about the decline in global inequality, it is simply a matter of fact that humans tend to care much more about their relative status compared to their neighbors, what is commonly called "keeping up with the Joneses". There is even a popular movie with Charles Duchovny about this phenomenon. While advanced economies have also benefited from globalization, the gains have been very unevenly distributed with workers at the very bottom of the income distribution losing out. This surely contributed to the recent rise in populism across advanced economies, including Brexit and the election of Trump. While the backlash against globalization is very real, the reality of the matter is that protectionist and inward-looking policies are not going to solve any of the important issues at hand. To the contrary, beggar-thy-neighbor policies were tried in the 1930s and only worsened the global economic downturn. Similarly, Trump's protectionist policies will not benefit American workers and will only come at the expanse of the American economy.
Raising tariffs will only hurt American consumers and are unlikely to give American firms an edge.
Here the link:
Income share of the top 10%