Fears of the looming US recession have put the world’s media economy at risk, buffered only by the current elections and the upcoming Olympics. But according to a recent forecast on global ad released by Screen Digest in London, it is the Internet that will truly keep the global ad economy from sinking.

In fact, thanks to the increasing penetration of broadband in the market, and as users spend more of their time online, the power of online advertising will continue to soar to exponential heights in the coming years.

In an article published by Media Life magazine, senior Screen Digest analyst Vincent Letang said:  If it were not for the organic growth of online advertising, we would be contemplating a recession of advertising spending.

Letang expects it to grow below average GDP growth from 2008 to 2012, hitting an annual growth rate of 3.6 percent in Europe and 3.7 percent in the U.S. In the first two years of the forecast, 2008 and 2009, growth will be slower than the remaining years  2009 will be particularly slow. Most of this growth, he said will be from online advertising, which he expects to grow about 17 percent a year until 2012.

The Screen Digest forecast for internet’s share of the global advertising economy is actually in line with the recent forecast of The Kelsey Group, which released numbers predicting that global advertising will grow from $605 billion in 2007 to $707 billion in 2012, for an average annual growth of 2.7 percent.

But Kelsey predicts internet advertising in its various forms will grow 23.4 percent a year on average, reaching $147 billion in 2012, giving it a 21 percent share of the global ad market by 2012. That’s up from 7.4 percent at the end of 2007.