NEW YORK: Mobile ad spending in the US will leap more than 80% in 2014, putting it ahead of newspapers, magazines and radio for the first time, according to new figures from eMarketer.

The insights provider said that an $8bn increase in expenditure would push mobile's share to almost 10% and make it the third largest individual advertising venue, trailing only TV and desktops/laptops. Within two more years it expected mobile would move into second position behind TV, taking an 18.7% share.

"It really has to do with consumers' time, attention and engagement," Noah Elkin, eMarketer executive editor, told the Financial Times. "Consumers are spending more of their digital media time with their smartphones and tablets than their desktops and laptops."

The time spent on all these devices was more or less equal in 2013 but is diverging rapidly. US adults will spend an average of 2 hours 51 minutes per day with mobile devices this year, according to eMarketer's own estimates, or 23% more than last year, while time spent on desktops and laptops will dip 5% to 2 hours 12 minutes.

A total of $50.7bn will be committed to digital channels this year, split 65:35 between desktop and mobile; within four years a forecast digital spend of $82.2bn will be split 29:71.

The unstoppable rise of mobile will also boost overall advertising expenditure, which eMarketer forecast would increase 5.3% in 2014 to reach a total of $180.1bn. A broadly similar rate of annual growth is projected out to 2018, by when the total advertising market is expected to amount to $220.6bn.

While TV currently remains the biggest destination for advertising dollars, taking a 38.1% share in 2014, it will be eclipsed by digital come 2018 when TV's share will decline to 35.7% and digital's will hit 37.3%.

"Even as consumers spend more time consuming digital videos on their devices, they still spend more time on a daily basis watching TV," Elkin observed.

Warc's June International Ad Forecast expects digital spend in the US to total $49.4bn this year, accounting for 29.5% of a market worth $167bn.

Data sourced from eMarketer, Financial Times; additional content by Warc staff