A new report has a stern warning for the global workforce: stay flexible.

The McKinsey Global Institute cautions that as many as 375 million workers will need to switch occupational categories by 2030 due to automation.

The work most at risk of automation includes physical jobs in predictable environments, such as operating machinery or preparing fast food. Data collection and processing is also in the crosshairs, with implications for mortgage origination, paralegals, accounts and back-office processing.

To remain viable, workers must embrace retraining in different fields. But governments and companies will need to help smooth what could be a rocky transition.

"The model where people go to school for the first 20 years of life and work for the next 40 or 50 years is broken," Susan Lund, a partner for the McKinsey Global Institute and co-author of the report, told CNN Tech. "We're going to have to think about learning and training throughout the course of your career."

The authors believe we may see a massive transition on a scale not seen since the early 1900s, when workers shifted from farms to factories. The report also cited the potential need for an effort on the same scale as the Marshall Plan, when the United States spent billions to rebuild Western Europe after World War II.

Such a plan would include a big investment from the private and public sectors in new training programs and workforce transition programs.

Related: Robots: Is your job at risk?

Despite the looming challenges, the report revealed how workers can move forward. While the introduction of the personal computer in the 1980s eliminated some jobs, it created many more roles. Workers who are willing to develop new skills should be able to find new jobs.

"The dire predictions that robots are taking our jobs are overblown," Lund said. "Yes, work will be automated, [but] there will be enough jobs for everyone in most areas."

The authors don't expect automation will displace jobs involving managing people, social interactions or applying expertise. Gardeners, plumbers, child and elder-care workers are among those facing less risk from automation.

The takeaway: If you want to breathe easily, keep your people skills sharp.