Carat revised its global advertising spend predictions downward. The Aegis media buying agency network is now saying that global ad spending will slip 5.8%, down from its previous prediction of 4.8% growth (forecast last August).

Ad spend in the U.S. will be down a dismal 9.8%, from a previously forecast 3.1% rise, according to Carat (via MediaBuyerPlanner).The UK will be down more than 7%, while Western Europe as a whole will be down 6.6% (Germany-2.2%, France -5%, Italy -6.5%, Spain -16.5%).

Central and Eastern Europe will be down 8.2% for the year, compared to Carat’s previous forecast of 15.2% growth.

China will remain the biggest ad growth market, with spending expected to be up 4.6% this year, down from 11% previously forecast.

Carat predicts that there will be a small return to growth, of 0.7%, in 2010, according to Reuters.

In December, ZenithOptimedia cut its forecast for 2009, predicting US ad spend overall would fall 6.2%. That was down significantly from its previous revision, in October, when the group projected 0.7% growth for the year.

While ad spend in 2009 will likely suffer, Zenith believes a recovery will begin in the second half of the year, with mild year-on-year growth compared to the difficult second half of 2008.

A mid-term forecast from private-equity firm Veronis Suhler Stevenson predicted that overall media and communications spending will drop by 0.4% in 2009, but will still continue to outpace US economic growth.