Wim Bartels is one of Europe’s most seasoned voices in sustainability reporting. With over two decades of experience, he has advised more than 50 multinational and listed companies on ESG strategy, assurance, and disclosure. Today, he brings that expertise to his roles as senior partner at Deloitte, Chair of the Sustainability Policy Group at Accountancy Europe, and member of the Sustainability Reporting Board (SRB) at EFRAG, Europe’s financial and sustainability reporting advisory group.

In this interview, he reflects on his transition into ESG, the evolving role of auditors, and the latest developments around the European Sustainability Reporting Standards (ESRS) and the Omnibus proposal.

From balance sheets to carbon footprints: Bartels on shifting into ESG

Wim Bartels began his career as a financial auditor at KPMG in 1989 and joined their sustainability team in 2003. He describes the move from finance to sustainability as both challenging and transformative. Coming from a background in auditing and forensics, Bartels found the communication styles in sustainability vastly different. “That was hard,” he says. “To get on equal footing in terms of communication… to find each other.”

Equally daunting was the content itself. “I really stepped into this without any background,” Bartels admits. “What do we mean when we say carbon emissions? That’s not on the balance sheet. I can’t touch it. What is it?” The transition required a complete relearning of terminology and concepts.

Looking at today’s landscape, he notes that while the field has grown significantly, the rise of self-declared experts is troubling. “We need more professionals, not more ‘experts’,” he cautions. “Everyone starts calling themselves an expert after two years, and that undermines real expertise.”

In the end, the shift was more than a change in job – it was a shift in mindset. “It took me a while,” he reflects, “but it opened up a completely different way of thinking about value and impact.”

What sustainability demands from today’s accountants

Bartels sees this evolution unfolding along two paths: what’s already happening, and what should be happening.

In the short term, auditors will be instrumental in improving the quality of sustainability disclosures. “Auditors will no doubt add more confidence in the information being reported and more quality of the data,” he explains. Their involvement – reviewing documentation, checking reconciliations, flagging inconsistencies – raises the bar for companies, even if the process is still catching up with the complexity of the data.

But technical assurance is just part of the equation.

“The real role of auditors should go beyond checking the report,” says Bartels. “They should initiate the right conversations.” He believes auditors should apply the same forward-looking scrutiny they already use for tax planning or liquidity to sustainability risks. That means asking pointed questions: Are climate risks priced into the business model? Does the company have a plan to respond?

Because auditors operate at board level, they’re uniquely positioned to spark these discussions. In Bartels’ view, this advisory role isn’t optional – it’s part of their responsibility to represent not just shareholders, but wider society.

There’s a catch, though. “You can't learn it in one year,” he notes. “Any job, especially in ESG, takes experience.” That’s why he sees the current “pause” created by the Omnibus proposal as a critical window – a blessing even. Not for complacency, but for building internal capability. Audit firms need to train broadly across their teams, not just rely on niche sustainability units.

Will auditors and accounting firms use the ‘stop-the-clock’ period fully to their advantage?

Bartels sees this moment as a crucial opportunity for audit firms, but also a potential trap. “Auditors now have more time to prepare themselves,” he says. “Because it would have been quite a challenge in the first one, two, three years.”

Still, he’s not entirely optimistic. “The first signs I hear in the market are now saying: ‘Oh, it doesn't happen. So we don't have to pay attention to it. It's only for the very large companies, and we serve them anyway.’” This, he warns, is the wrong takeaway.

“If we continue that view, then we will again not be prepared,” Bartels cautions. Instead, he sees the delay as a strategic window – one that should be used to strengthen internal knowledge and broaden assurance readiness beyond sustainability specialists. “This is the time to educate a sufficient number of people, so that once we scale up again in future, we are prepared to serve a wider group of companies.”

Audit firms that treat this period as a chance to build institutional knowledge and train broadly will be better positioned when CSRD scope expands again. Those that wait risk falling behind – both in expertise and credibility.

The pause may reduce immediate pressure, but the direction of travel is clear. As Bartels puts it: “Sustainability will also stay. Climate change did not pause, right? That continues.”

What does stepping back from reasonable assurance mean?

The Omnibus proposal recommends delaying mandatory reasonable assurance under CSRD. Bartels sees this not as a setback, but a necessary recalibration.

“With the current challenge of auditors, I don’t think that is a negative thing as such,” he says. Scaling to reasonable assurance too quickly would have driven up costs and deepened resource gaps. “It would have created criticism that auditors are just making money out of this. And it would also have created further resource challenges.”

Still, he stresses that limited assurance is not a free pass. “You need to be sure yourself that the information is correct,” he says. “Limited assurance is what we do – but you are responsible for accuracy and completeness. So the company itself needs to be reasonably assured that they provide high quality information.”

He also points to a widespread misunderstanding: “Many users misinterpret limited assurance. They just go: ‘Oh, the auditor looked into it, so it’s okay.’” In reality, the distinction between limited and reasonable assurance is often overstated, at least in terms of perception.

Bartels sees a strategic opportunity here. Some companies – like Philips and DSM – have voluntarily pursued reasonable assurance to signal leadership. “It’s a great opportunity for accountants to ask: how important do you really believe this information is? And what does that mean for the external level of comfort you want to add to it to show your stakeholders the importance you attach to your reporting?”

The shift may lower pressure, but not expectations. Quality still matters – assurance or not.

How will EFRAG determine which data points are ‘least important’?

The European Commission has tasked EFRAG with simplifying the ESRS by identifying and removing at least 25% of the data points deemed less relevant for general-purpose sustainability reporting.

Bartels outlines a stakeholder-centric approach. “We have been out until 6 May with a call for public feedback,” he says. “We have one-on-one interviews with companies, investors, auditors, NGOs, and academics to get their views.” The goal is to understand which disclosures create the most burden or deliver the least value.

“That is the input for our further analysis,” he explains. The goal is to determine what is essential – and, just as importantly, what isn’t. EFRAG will also develop internal criteria to guide decisions, weighing relevance alongside reporting burden.

Bartels emphasizes that this process isn’t just about cutting 25% of data points. “That 25% is a kind of guideline,” he says. Not all data points are created at equal efforts. EFRAG is also considering the qualitative burden, i.e. whether it’s very cumbersome and challenging to collect the information, especially when the impact is minimal.

Will EFRAG distinguish more clearly between mandatory and voluntary data points?

EFRAG’s current focus is on reevaluating its mandatory disclosure requirements, with particular attention to potentially relaxing certain “shall” data points. “The emphasis will be on determining whether some of the ‘shall’ disclosures could become ‘may’,” explains Bartels. “This shift will be based on feedback from companies, investors, and other stakeholders—essentially, we’ll use the input we get from the market.”

While the process includes reviewing voluntary disclosures, that’s not the main objective. “We’ll also look at whether some of the ‘may’ disclosures should actually be elevated to ‘shall’,” Bartels notes. “For instance, if most companies are already reporting them, or if users consistently demand that data.”

EFRAG is also considering alternative treatments for the remaining voluntary data points. “Some of the ‘may’ points might be turned into guidance or flagged differently,” he adds, highlighting a broader goal of optimizing the relevance and burden of disclosure standards.

Can EFRAG deliver under pressure with its current structure?

“I don’t think the structure is the problem,” says Bartels. After initially expressing concern over the pace of EFRAG’s implementation planning during an SRB meeting on April 15th, he points out that progress was made quickly. “Significant improvements were made in just over a week, and we were able to approve the plan as a board.”

That, for Bartels, shows the existing setup is capable of responding – at least in the short term. “Within the current SRB structure, we were able to move forward,” he says.

As for deeper structural reform, that’s not within the SRB’s control. “We cannot decide on that,” Bartels notes. “That’s up to the administrative board or the European Commission.”

The focus now is on organizing the work to meet compressed timelines. “We’re currently discussing how we’re going to structure it in the context of the speed that we need,” he adds.

Is there enough time to revise the ESRS?

“It’s very tight,” says Bartels, when asked whether EFRAG can meet the timeline set by the European Commission to revise the ESRS. The group is expected to deliver simplified standards quickly – without the benefit of a full public consultation.

Still, Bartels remains cautiously optimistic. “We don’t need to develop new standards – we need to simplify,” he explains. That difference matters. EFRAG already has a foundation to work from. “If we’ve designed a proper approach to take out data points or improve interoperability, we can move relatively quickly.”

Even so, he acknowledges the trade-offs. “Principally, no – we don’t have enough time,” he says. “But I think we will be able to make it to a large extent.”

Is EFRAG planning to change how double materiality is applied?

“The principle will stay as is,” says Bartels. “Double materiality – looking at both how sustainability impacts the company and how the company impacts the environment and society—remains the foundation.” 

While the core concept isn’t changing, Bartels notes that EFRAG is focused on helping companies apply it more effectively. “We will be looking into the double materiality approach,” he explains. “The Commission has suggested it needs to be further clarified and simplified.”

That likely means a less formal, less burdensome process. “The main criticism is that the current approach is far too detailed. Companies are spending too much time answering questions they already know the answer to,” he says. “We need to simplify, without losing sight of the key material issues.”

EFRAG is still deciding how these changes will be delivered – possibly through an updated implementation guideline (IG1), amendments to the existing standards, or new clauses added directly into the framework. “That is now to be seen, what is the best approach,” says Bartels.

Was the development of the Omnibus Proposal rushed or reasonable?

“It was indeed very fast,” says Bartels, referring to the rapid development of the Omnibus Proposal. But while the pace raised eyebrows, he doesn’t see it as cause for concern. “I’m personally not so concerned about the process,” he says. “The Commission didn’t just start collecting feedback when they began drafting. They’ve been hearing these concerns for two years already.”

He points out that the process wasn’t closed-door. “They organized a two-day meeting to collect feedback from a broad set of stakeholders – not just companies, but also users, NGOs, and academics,” Bartels explains. “And they’ve spoken with individual stakeholders as well. So yes, it was fast, but not rushed in the dark.”

That speed, he argues, should be seen in context. “Could they have taken longer in a normal situation? Yes, but we are in somewhat exceptional times with security, competitiveness and sustainability playing out at the same time. But this is a proposal. It now goes to political groups and stakeholders for discussion.”

To Bartels, the compressed timeline reflects the pressure regulators are under to address implementation issues – especially around reporting burden – without losing momentum. “It’s not the final word. It’s the start of the next phase,” he says.

And what about the content of the proposal itself?

When it comes to the content of the Omnibus Proposal, Bartels is measured, but clear. “In general, the simplification – I’m behind that,” he says. “I believe that the ESRS are good. Otherwise, I shouldn’t have signed off at the time”, referring to his role as an EFRAG SRB member.

Still, he acknowledges that the practical application of the ESRS has gone beyond what was intended. “We need to look into the standards,” he says. That’s exactly what the Omnibus Proposal aims to do: scale back requirements that are difficult to implement or of limited material relevance.

On the change in scope – from 250 to 1,000 employees – Bartels is more cautious. “That is really a political point,” he notes. “You can argue about it for ages – whether it should be 100, 500, or 1,000.” From his perspective, sustainability reporting should cover those who collectively contribute most to the economy. “With 1,000, you capture a lot. But if you look at the economy as a whole, the threshold should be much lower.”

Still, he expects larger companies to continue pushing sustainability requirements down their value chains. “We will still see small companies being included because large companies will ask for it,” he says. “They’ll say, ‘It is my strategy, and I need you on board.’”

Will amendments to the Proposal be made?

“I’m pretty sure that amendments will be made,” says Bartels. Given the breadth of the Omnibus Proposal and the range of views across political parties, some degree of negotiation is inevitable. “There must be areas where they will mediate and negotiate,” he adds. “Just because there are divergent views.”

“There’s a lot of content in the proposals and there are divergent views,” he explains. One of the main flashpoints is scope – specifically, the proposal to raise the CSRD threshold from 250 to 1,000 employees. “Personally, I expected it might go down,” Bartels says. “There’s been a lot of pushback, also from the financial sector.”

But the political landscape is fluid. “To be honest, now I’m no longer absolutely sure,” he adds. “Some say it will go further up.” It’s possible that negotiations will center on other areas entirely, with scope becoming a bargaining chip.

What’s clear is that the proposal, in its current form, won’t pass unchanged. “The scope issue is a big discussion point,” says Bartels – and it’s just one of many that will shape the final outcome.

What role will software play in ESRS reporting?

“Software is a fundamental element for proper reporting in future” says Bartels.

As sustainability reporting becomes more data-intensive, manual processes are no longer enough. “We’ve seen too much manual data collection without properly documented controls, without proper reconciliations,” he explains. “Much was done in Excel, which results in errors being easily made.”

Bartels sees software as critical not just for efficiency, but for accuracy and audit-readiness. “Companies will move there to capture the data in an efficient and controlled manner,” he says.

What practical steps do you recommend for companies no longer in scope of CSRD?

“Even when the scope goes up, CSRD will stay”. As will sustainability: “Climate change has not paused.”

For companies previously expecting to report under CSRD, Bartels advises against abandoning efforts. “This is the moment to take the CSRD, use it as a management framework, and then see: where do we need to focus our strategy when it regards sustainability? Where do we need to set targets? Where do we need a policy?”

The extra time should be seen as an opportunity – not a pause. “The Wave 2 and 3 companies have another two years to prepare. That is a great relief for them. But stopping would not be the right thing to do.”

Bartels encourages companies to shift from a compliance mindset to a strategic one. “Work on these in the coming two years,” he says. “Don’t wait another one or two years and then start preparing for the reporting again.” Instead, use the CSRD framework to identify risks, clarify priorities, and embed sustainability into core operations.

As he puts it: “This is not just about reporting. It’s about how you run your business in a changing world.”