Inequalities in consumption are stark. Globally, the 20% of the world’s people in the highest- income countries account for 86% of total private consumption expenditures — the poorest 20% a minuscule 1.3%.

More specifically, the richest fifth of the world's population:

Runaway growth in consumption by the richest fifth of humanity is putting strains on the environment never before seen,and the above inequalities have not changed significantly into the 21st century.

What can be done about the resulting challenge of inequality to global security, stability, shared prosperity, and most fundamentally to global social justice?

Because global markets work better for the already rich (be it with education or for countries with stable and sound institutions), we need something closer to a global social contract to produce a global polity and address unequal endowments –to increase educational opportunities for the poor and vulnerable, and to help countries build sound institutions. Because global markets are imperfect, we need global regulatory arrangements and rules to manage the global environment (Kyoto and beyond), help emerging markets cope with global financial risks (the IMF and beyond), and ways to discourage corruption and other anti-competitive processes (a global anti-trust agency for example). And because global rules tend to reflect the interests of the rich, we need to strengthen the disciplines that multilateralism brings, and be more creative about increasing the representation of poor countries and poor people in global fora – the IMF, the World Bank, the UN Security Council, the Basel Committee on Banking Regulation, the G-8, and so on. But even if all of this could be achieved and there were equal shares for all, there are simply not enough resources for the lifestyles of the rich Western nations to be made universal.  Comparative calculations of carbon footprints indicate that between three to nine Earths would be required to provide the resources needed.  To have a global uptake of the Western lifestyle would require basic production systems to reduce their environmental impact by a factor of 10, when already the international community seems unable to make a 50% reduction in carbon emissions by mid century.