... climb at a similar pace throughout eMarketer’s forecast period, which extends through 2016. By that year, eMarketer forecasts, worldwide ad spending will top $628 billion.

The fastest growth during the forecast period will come from Latin America, where ad spending is up 11% this year to $34.66 billion. By 2016, ad spending in Latin America will reach $51.33 billion.
Asia-Pacific, Eastern Europe and the Middle East and Africa will also enjoy higher-than-average growth rates, while growth in North America and Western Europe will be significantly slower.
This year, Western Europe has struggled to grow ad spending at all, with several major countries posting spending declines.
Japan is the world's second largest nation in terms of ad spending,al though China is hard on its heels and set to surpass it in 2014.
Moreover, China, the third-largest ad market in the world, is growing much more quickly in terms of adspend than mature markets like the US or Japan.
eMarketer estimates ad spending in China is up 13% this year, slightly higher than Warc’s November 2012 projection of 11.5% growth.
Research firms that predicted significantly higher growth rates tended to make those forecasts earlier in 2012, when overall economic prognostications for China were more favorable. Nonetheless, eMarketer predicts double-digit ad spend growth rates in this massive country through the rest of the forecast period, which will help boost Asia-Pacific (and worldwide) increases.
Read the original unabridged eMarketer article.