McKinsey lists “four powerful forces [that] are disrupting the global economy”.

• “shift of economic activity to emerging-market cities
• “acceleration of technological change. While technology has always been transformative, its impact is now ubiquitous, with digital and mobile technologies being adopted at an unprecedented rate. It took more than 50 years after the telephone was invented for half of American homes to have one, but only 20 years for cellphones to spread from less than 3% of the world’s population to more than two-thirds. Facebook had six million users in 2006; today, it has 1.4 billion… The mobile Internet offers the promise of economic progress for billions of emerging-economy citizens at a speed that would otherwise be unimaginable. And it gives entrepreneurial upstarts a greater chance of competing with established firms. But technological change also carries risks, especially for workers who lose their jobs to automation or lack the skills to work in higher-tech fields.
• demographics – the possibility that world population could plateau or actually start to fall
• globalization

There are a few more things out there that could disrupt the economy for better or worse – renewable energy? biotechnology? climate change? risks to food and water supplies? ocean collapse? nuclear or biological war?