At the start of a new decade, many commentators are understandably focused on the health of the global economy. GDP growth this decade most likely will be lower than during the teens, barring a notable improvement in productivity in the West and China, or a sustained acceleration in India and the largest African economies.

Until we have final fourth-quarter data for 2019, we won't be able to calculate global GDP growth for the 2010-2019 decade. Still, it is likely to be around 3.5% per year, which is similar to the growth rate for the 2000s, and higher than the 3.3% growth of the 1980s and 1990s. That slightly stronger performance over the past two decades is due almost entirely to China, with India playing a modestly expanding role.

Average annual growth of 3.5% for 2010-2019 means that many countries fell short of their potential. In principle, global GDP could have increased by more than 4%, judging by the two key drivers of growth: the size of the workforce and productivity. In fact, the 2010s could have been the strongest decade of the first half of this century. But it didn't turn out that way. The European Union endured a disappointing period of weakness, and Brazil and Russia each grew by much less than in the previous decade.

The prospects for the coming decades are not as strong.

China's labor-force growth is now peaking, and the populations of Japan, Germany, Italy, and other key countries are aging and in decline. True, some countries and regions that underperformed in the teens could now catch up; but much will depend on the realization of several positive developments.