Global spending on public cloud Relevant Products/Services services for IT will grow at a rate of more than 26 percent over the next four years -- five times faster than the IT industry overall. That's the projection of a new forecast Tuesday from research firm International Data Corp.

The study, Worldwide and Regional IT Cloud Services 2012-2016 Forecast, projects that spending in 2012 on public clouds will reach more than $40 billion, and will hit $100 billion by 2016. This reflects a general trend by companies to increasingly move their operations to cloud services.

'Transformative Period'

Frank Gens, senior vice president and chief analyst at IDC, said in a statement that the IT industry is in the "midst of an important transformative period," as companies invest in technologies such as cloud computing and storage. "By the end of the decade," he said, "at least 80 percent of the industry's growth, and enterprises' highest-value leverage of IT, will be driven by cloud services" and other technologies.

Gens said that the forecast, the fifth annual one on this topic since 2008, marks the transition of cloud investment priorities from "simply improving IT operations to delivering business Relevant Products/Services innovation."

The study envisions that small- to medium-size businesses will rise as a more critical customer Relevant Products/Services segment, and that platform-as-a-service (PaaS), which IDC said had a slower than expected start this year and last, will become "the strategic foundation" of the new cloud services marketplace. In fact, the study projects that PaaS rollouts will accelerate over the next year and a half, and that this growth will be critical to the continuing momentum of cloud services.

IDC envisions that, by 2016, 16 percent of IT revenue will be based on public IT cloud services in five areas -- applications, system infrastructure Relevant Products/Services software Relevant Products/Services, platform as a service, servers and basic storage. By that year, cloud services will provide more than 40 percent of all growth in these areas.

Software-as-a-Service

On the spending side, software-as-a-service, combining both apps and infrastructure as a service, will be the largest category over the next five years, according to IDC. However, the research firm said that storage and platform as services will show faster growth.

The study also said that the U.S. will continue to be the largest public cloud services market, followed by Western Europe and Asia/Pacific, not including Japan. By 2016, however, public IT cloud services will see a boom in emerging markets.

The projections do not include private cloud deployments, which are generally confined to use by a specific company. Public IT cloud services, in IDC's definition, are those offerings available on a commercial basis to a general, unrestricted market. The two will become more alike in some ways, IDC said, such as public clouds' incorporation of the security Relevant Products/Services and availability capabilities that are now more frequently associated with private clouds.