Addressing within-country inequality may be the political imperative of the moment. But tackling vastly greater cross-country disparities – especially those affecting the two-thirds of humanity living outside the advanced economies and China – is the real key to maintaining geopolitical stability in the twenty-first century.

CAMBRIDGE – What is remarkable about the increase in nationalist sentiment across the developed world in recent years is that it is occurring at a time when many of today’s most pressing challenges, including climate change and the COVID-19 pandemic, are fundamentally global problems demanding global solutions. And the anger brewing among citizens of vaccine-poor countries – basically, the two-thirds of humanity living outside the advanced economies and China – could come back to haunt the rich world all too soon.

US President Joe Biden’s ambitious plans to address inequality in America are to be welcomed, provided the administration succeeds in covering the long-run costs through higher taxes or stronger growth, admittedly two big ifs. So, too, is the smaller but still significant Next Generation EU scheme to help European Union members such as Italy and Spain that have been disproportionately affected by the pandemic.

The 16% of the world’s people who live in advanced economies have had a tough pandemic but are now looking forward to a recovery. China, which accounts for another 18% of the world’s population, was the first major economy to rebound, thanks mainly to its better epidemic preparedness and greater state capacity to contain the coronavirus.

But what about everyone else? As the International Monetary Fund highlights in its April World Economic Outlook, there is a dangerous global divergence. The horrific wave of COVID-19 in is likely a preview of what is still to come across much of the developing world, where poverty has exploded. Most countries are unlikely to return to their pre-pandemic output levels until at least the end of 2022.

Until now, the twenty-first century had been a story of catch-up for the developing world, far more so than had seemed likely in the 1980s and 1990s. But the COVID-19 crisis has hit poorer countries just as the rich world is waking up to the fact that containing both the pandemic and the looming climate catastrophe depends hugely on the efforts of developing economies. That is not to mention the cooperation likely to be needed to contain terrorist groups and rogue-state actors in a world seething about the global inequities that the pandemic has laid bare.