McKinsey had four global growth scenarios out to 2025

McKinsey believes three sets of forces will shape the global economy over the coming decade. The first two are stimulus policies and shifting energy markets. These are near-term forces, whose effects are felt on a daily basis. The next two forces, urbanization and aging, are powerful, inexorable trends aggravating ongoing structural challenges. Finally, two forces are of uncertain and variable magnitude: technological innovation and global connectivity. All of these trends could intermittently disrupt and transform sectors.

The Past ten years were bad for the world economy

McKinsey forecasts two scenarios better than the 30 year world growth average and two below

Overall the demographics will be poor for economic growth

However, Offsetting the aging population is the fact that urbanization will continue to increase.

High-tech innovations in robotics and 3-D printing could enable mature and emerging economies alike to boost labor productivity and rapidly expand industrial horizons, while also shifting global trade patterns.

So at least some level of automation will be needed to offset the aging workforce.

Best case – By 2025, the global economy will have grown to $90 trillion in constant 2015 dollars, from $62 trillion in 2015. [3.7% average global growth]
Pretty good but bumpy – Global growth reaches 3.2 percent a year over the course of the decade, a relatively high historical level, and by 2025 the global economy reaches $88 trillion in 2015 dollars.
New slower normal – the global economy reaches $86 trillion in 2015 dollars.
Slow with Rolling regional crises – World economy is 78.6 trillion in 2015 dollars.

SOURCE- McKinsey