The global market for public cloud services will be worth more than US$40bn by the end of this year, and is likely to be valued at US$100bn in 2016, according to IDC.

This massive growth rate will be five times that of the IT industry overall, according to the market report.

This means that by 2016, public IT cloud services will account for 16% of IT revenue in applications, system infrastructure software, Platform-as-a-Service (PaaS), server and basic storage.

IDC SVP and chief analyst Frank Gens said Software-as-a-Service will receive the largest share of public cloud spending over the next four years, but heavy investment will also be made in storage and PaaS, areas seen as critical for the delivery of cloud.

Emerging markets will account for the growth of public cloud services, but the US, followed by Western Europe and Asia Pacific (excluding Japan) will maintain market share geographically.

“The IT industry is in the midst of an important transformative period as companies invest in the technologies that will drive growth and innovation over the next two to three decades,” Gens said.

“By the end of the decade, IDC expects at least 80% of the industry’s growth and enterprises’ highest-value leverage of IT, will be driven by cloud services and other third platform technologies.”

Eventually, according to Gens, the public cloud market will mature, increasing its attractiveness for those companies currently using a private cloud.

UK-based cloud hosting provider ElasticHosts CEO Richard Davies said IDC’s findings come as no surprise, with services driven by flexibility, scalability and the lower investment required to use the Cloud.

“As technology refreshes come round it makes sense that people would look to adopt this type of solution,” Davies said.

He did warn, however, that some of the services market share could end up being confused with offerings that aren’t technically seen as fitting the cloud model.

“There are a number of ‘fake clouds’ out in the market just selling traditional contracts with the world flexible included to take advantage of the buzz,” Davies said.

IDC said it defines public IT cloud services s those that have been designed for large unrestricted marketplace of potential users, whereas a private cloud is designed for a specific user.