Today, megaregions range in size from 10 to 50 million people — and in some cases, in the developing world, even more. They produce hundreds of billions — and sometimes trillions — of dollars in economic output. They harness human creativity on a massive scale, and they are the source of the lion’s share of the world’s scientific achievement and technological innovations.
The megaregions of today perform functions that are somewhat similar to those of the great cities of the past — massing together talent, productivity, innovation, and markets. But they do so on a far larger scale. Furthermore, while cities in the past were part of national systems, globalization has exposed them to worldwide competition. As the distribution of economic activity has gone global, the city-system has also become global — meaning that cities compete now on a global terrain. This means that bigger and more competitive economic units — megaregions — are required to survive and prosper.
Population is not tantamount to economic growth. Unlike megacities, which are termed as such simply for the size of their populations, megaregions are by definition places with large markets, significant economic capacity, substantial innovation, and highly skilled talent, as well as large overall populations.
A megaregion must meet three key criteria. First, it must be a contiguous, lighted area with more than one major city center. Second, it must have a population of 5 million or more. Finally, it must produce more than $100 billion in goods and services. By that definition, there are some 40 megaregions in the world. If we take the largest megas in terms of population:
- The 10 biggest are home to 666 million people, or 10 percent of world population.
- The top 20 comprise 1.1 billion people, 17 percent of the world population;
- The top 40 are home to 1.5 billion people, 23 percent of global population.
