• Marketers this year are expected to spend $128 billion on retail media.

• Some of this uptick is coming at the expense of traditional channels, Google, and trade budgets.

• In the US, Amazon, Walmart, and Instacart are leading the way in retail media.

Marketers this year are expected to spend $128 billion on retail media, or advertising on ecommerce sites, according to a new global forecast from the marketing research firm WARC.

Retail media — which WARC forecasts to be up 10.2% over last year and to grow another 10.5% next year — appears to be coming at the expense of Google search and traditional offline media channels like linear TV, experts said.

Retail media has become one of the hottest categories in advertising in the past couple of years, partially due to marketers who are worried about the economy investing in ads that more directly drive purchases, experts said.

Alex Brownsell, WARC head of content, said some of this uptick is coming at the expense of traditional channels, such as linear TV, print newspapers and magazines, and audio.

Spend on linear TV is expected to drop by 5.4% this year, bringing its share of total global ad dollars down to 16.3%, according to WARC. Ad budgets placed on "newsbrands and magazines" will fall 5.9% and audio down by 0.8%. Meanwhile, retail media is forecast to grow its share to 13.3% of total ad spending.

Retail media players are also managing to capture some search spend that was ordinarily placed with Google, according to Bill Fisher, Insider Intelligence principal analyst. US search spend on retail media properties is expected to grow 18.7% this year, while search spend outside retail media is expected to grow just 5%, per Insider Intelligence.

Google has careened back and forth over different shopping strategies and cycled through a handful of e-commerce leaders over the years as it sought to take on Amazon to become the first choice of shoppers. Despite offering Shopping Ads and analytics and order management tools, industry analysts usually don't consider Google as a retail media operator.