Unveiling its latest set of forecasts for global ad spend, Zenith said that since it released its last forecasts in December, "the global ad market has taken a substantial turn for the worse", noting that "trade has fallen off rapidly, dragging many developing markets into the downturn".
Outlining the situation, Zenith said the downturn began "in Q3 2008, accelerated in Q4, and Q1 2009 was at least as tough as the preceding quarter".
It warned that "as we enter Q2, there is limited long-term visibility in the market, as most advertisers wait until the last moment to confirm their spending commitments".
All the major markets in Western Europe are suffering substantial decline in ad spend: in 2009 Zenith forecasts a 7.3% decline in France, 5.5% in Germany, 5% in Italy, 10.1% in Spain and 8.7% in the UK.
However, Zenith said it expects all major markets "to increase in 2010, with the exception of Italy".
Ad spend across Asia Pacific is forecast to drop by 3.4% in 2009, while ad spend in central and eastern Europe will suffer the sharpest drop-off in 2009, of 13.9%. Overall, it expects ad spend to shrink 2% in Latin America in 2009.
By medium, Zenith said the internet is the only medium it expects to attract higher ad spend in 2009, "thanks to its accountability and innovation in ad formats".
It forecasts an 8.6% increase in global internet expenditure in 2009, down from 20.9% in 2008. Global television ad spend is predicted to fall 5.5% in 2009.
This year, TV will retain its status as the medium with the biggest share of global ad spend, with 38.6%, up from a 38.1% share last year.
Newspapers' share of ad spend is tipped to decline from 25.3% last year to 21.6% in 2011, while Radio's share of global ad spend is predicted to decline from 7.8% last year, to 7.2% in 2011.
Read this week's Media Week, out tomorrow 15 April, for further analysis of the Zenith forecasts.