Google is warning publishers that online visitor traffic – which drives ad revenue – could plummet as much as 45 per cent if the contentious Copyright Directive being considered by European lawmakers goes forward.

The European Parliament is trying to revise its copyright regime and the proposed alteration includes two articles loathed by Google and other tech and media firms.

One is Article 11, popularly referred to as the "link tax," which would allow online publishers to decide who can link to their news stories and to demand a fee for the privilege. To avoid paying, Google might choose to present only minimal text and and no images in its search results, which would make it more difficult to evaluate whether a link might be worth clicking.

The other is Article 13, which would require internet platforms to implement and deploy a system for preventing the unauthorized publication of copyrighted content. In effect, it would replace the beg-forgiveness takedown system with preemptive upload filtering.

Negotiations among EU member states have stalled, thanks to disagreements between France and Germany, among others. Part of the discussion involves whether internet firms with revenue below €10m ($11.3m) should be exempted from filtering requirements.

In the meantime, we have lobbying, which heated up last year and has continued since.

Nice business you've got there, be a shame if something happened to it

Google has faced restrictions on how it can present copied content before, specifically in Spain five years ago: It shutdown the Spanish version of Google News in 2014 after Spain altered its copyright law to allow news publishers to charge aggregators like Google News for including snippets of summary text alongside their links.

A study commissioned by Spanish publishers in 2015 found that the law cost publishers an estimated €10m (~$10.9m at 2015 exchange rates) annually and led to a loss of visitor traffic. Belgium tried something similar in 2007 and reconsidered four years later.

If Article 11 goes forward, Google, as it has said before, contends publishers will suffer. In a blog post on Thursday, Kent Walker, Google's SVP of global affairs, described a search experiment the company ran to understand the impact of showing only URLs and minimal text without preview images.

"All versions of the experiment resulted in substantial traffic loss to news publishers," he said. "Even a moderate version of the experiment (where we showed the publication title, URL, and video thumbnails) led to a 45 percent reduction in traffic to news publishers."

Walker argues Article 11 should be modified to allow the sharing of facts and preview material – text and images – to provide enough context for those conducting searches to understand what awaits them when they click a link.

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Google might also be able to work around publisher permission requirements by using machine learning and/or crowdsourcing to rephrase protected text and generate substitute images, though that might burn through more CPU time and underpaid Mechanical Turkers than its worth. Or it could just pay up and share its ad wealth.

Worries about Article 13 are greater still, enough to prompt more than 4m people to sign a petition against an upload filtering regime and letters from a variety of concerned parties. A potential problem with Article 13 is that limitations on media sharing could affect firms like GitHub and organizations like Wikipedia.

Disagreements among EU lawmakers could be resolved in the next few days or anytime before the last plenary session of Parliament in April. Julia Reda, a member of the European Parliament and a representative of the Pirate Party in Germany, anticipates a decision could be reached next week.

Whatever happens, copyright restrictions won't address the fundamental problem facing publishers – the fact that Facebook and Google dominate the online ad business and online content discovery channels. The emergence of Amazon as a third major ad platform isn't likely to improve matters. ®