The group's figure is also symbolic in the campaign to address plastic waste. Among the events that sparked the recent escalation in public concern on plastic was the publication by Greenpeace of its 'Bottling It' report.

Coca-Cola's refusal to divulge the figure in this report, published two years ago, was a "non-finding" the campaigner made the most of. Soft drinks companies have been relentlessly pursued by campaigners; Coca-Cola, PepsiCo, Nestle and Danone have all now signed up to the Global Commitment.

All that, as they say, is history. This is a big moment in the campaign against plastic, but the Global Commitment is not only about making companies declare benchmark figures, but also about setting and reporting regularly on more ambitious goals.

Conrad MacKerron, senior VP at US-based campaign group As You Sow, believes it's "great to see several large companies disclosing plastics use, so we have a baseline to track future reductions". However, he warns: "The biggest challenge going forward may be how to motivate companies to stay on track and monitor their progress."

Coca-Cola's disclosure is also significant in a broader context. How and what companies report, when it comes to sustainability, is closely linked to the wider issue of transparency. Consumer purchasing decisions are increasingly being based on brands' environmental or social record. Withholding significant information or misreporting on these matters could be said to be every bit as reprehensible as misleading advertising.

Two years ago, a campaigner was railing against Coca-Cola's failure to disclose. Today, in order to benefit from the credibility of partnering with the Ellen MacArthur Foundation, thereby being seen as "part of the solution", Coca-Cola has had to step up its game, both in terms of action and openness.

However, Coca-Cola still has plenty of scope to engage publicly in a way that casts itself in the most positive light. The group wants its 'World Without Waste' programme, launched in early 2018, to be the hero, not Dame Ellen MacArthur, for all her derring-do on the high seas and now in the corridors of power.

"Since the launch of World Without Waste, we have begun to speak more openly about our packaging footprint," a Coca-Cola spokesperson says. "This will continue to be the case, because we believe that transparency is paramount."

Paramount is an absolute term, and so is transparency, but both could be said to be relative in this context. The spokesperson goes on to say: "The information in the report had been shared over 2018-2019 with external stakeholders, with the understanding that they might share it externally; this would be the first public posting of the information."

In other words, if you're expecting to find the words "We produce three million tonnes of plastic every year" emblazoned on the Coca-Cola website in 30-point font, you should adjust your expectations.

Despite campaigners finding that both their carrots and sticks are proving more effective in a changed consumer and investor environment, the world order has not been turned on its head. Even under the stipulations of the Global Commitment, companies have considerable flexibility in the commitments they make and how they schedule their reporting. PepsiCo, for example, chose not to disclose its total plastic tonnage in the latest report, but has confirmed its previous commitment to do so later this year.

Transparency on sustainability issues is not just about how companies present themselves to consumers. These topics are subject to major policy interventions, so there's an overlap with the broader question of transparency in how companies engage politically. The plastics debate has a very clear example of this in the debate about extended producer responsibility (EPR) and initiatives such as deposit return schemes.

As You Sow has criticised Coca-Cola for lobbying against bottle laws in the US and for taking an inconsistent line on these issues in different countries. 

"It is unfortunate Cola-Cola seems to have double standards on policy, acquiescing to deposit laws in Scotland and UK, when it became obvious they were going to be enacted, but continuing to oppose them in the US, where more state deposit or EPR laws are badly needed to increase recycling rates," MacKerron says.

Responding to this contention, the Coca-Cola spokesperson says: "We fundamentally believe that there is no 'one-size fits all' approach, and that different things can work in different places. This is true for infrastructure and policy, which often go hand in hand.

"Collection and recycling should happen in the most efficient ways possible. Sometimes, infrastructure is self-sustaining based on the value of recycled material, and sometimes it requires an incentive or subsidy. We are working to understand, develop or enhance the right systems for each market where we operate."

Interestingly, four drinks firms - Diageo, A-B InBev, Coca-Cola and PepsiCo - were included in a report on political engagement published by Transparency International UK last November. It is fair to say that none performed well.

Diageo was the only company of the four to receive the report's lowest F rating which showed "very poor standards". 

In response, a Diageo spokesperson says: "Whilst we welcome Transparency International's ambition to raise standards, we disagree with their assessment. By relying solely on publicly available information, we believe their approach does not take into account how multinational businesses operate and have to adhere to all relevant legislation and codes of practice. We are proud of our global compliance and ethics standards."

A-B InBev and PepsiCo were both rated "poor" by Transparency International, and both chose not to comment on the report. Coca-Cola had the highest score of the four, being rated as demonstrating "fairly poor standards".

Coca-Cola also chose not to comment on the report specifically. The company's spokesperson said partnership was a "key action pillar" of the World Without Waste programme, which includes partnering with governments. "We are - and will be - partnering in new ways with non-governmental organisations, suppliers and customers, peers and competitors, broader industry and governments to tackle these issues."

The greater focus on sustainability by consumers, along with the conscious-consumerism trend, has brought about a significant moment in the campaign to address plastic waste. The same pressures may, in time, lead to changes in how companies engage politically, which, given they operate in sectors where significant and sensitive policy debates abound, will have major implications for drinks firms.

These changes aren't happening overnight, but the centre ground on what it is to be transparent, what is legitimate PR and what is obfuscation and, ultimately, what is acceptable, is shifting. As is generally the case when it comes to areas of public concern, companies that are ahead of the curve will be seen as progressives, while those that fail to see the way the wind is blowing will be cast as the laggards.

This article originally appeared on just-drinks.