The Evolving Role of Chief Sustainability Officers

Ellen Weinreb, a seasoned professional with over 25 years of experience at the intersection of sustainability and human resources, has played a pivotal role in the recruitment and consulting space.

As the founder of the Weinreb Group and executive research firm established in 2008, she has been instrumental in identifying and placing sustainability and ESG leaders, including Chief Sustainability Officers (CSOs).

In 2011, Weinreb released the inaugural Chief Sustainability Officer Report, offering insights into the experiences of top sustainability executives worldwide.

Since then, the Weinreb Group has continued to publish a new CSO report approximately every two years, with the 2025 edition surveying a record 215 CSOs — highlighting the growing prominence of sustainability leadership within corporate structures.

Through her expertise in recruitment and thought leadership, Weinreb has significantly influenced the evolution of sustainability reporting and the integration of sustainability into corporate strategies.

Inside the 2025 report

The Weinreb Group’s latest report highlights how political regulations are shaping corporate sustainability strategies. 

In 2025, nearly 90% of surveyed CSOs reported spending more time on regulatory compliance than they did two years ago, whilst 60% cited regulation as their biggest challenge – more so even than budgets and resources.

This shift has led to a restructuring of sustainability departments, seeing the percentage of CSOs reporting to legal teams more than doubling since 2023.

“We are increasing legal collaboration across many aspects of our programmes, including regulatory compliance on climate, human rights and biodiversity,” says Renee Henze, CSO of IFF.

“I report into general counsel, as does our public affairs team, with whom I work closely.”

The introduction of Europe’s Corporate Sustainability Reporting Directive (CSRD) and state-level regulations in the US, particularly in California, has put even more pressure on companies to ensure their sustainability efforts align with legal standards. 

With reporting frameworks now carrying the same level of scrutiny as financial disclosures, it’s fair to say that the role of the CSO has never been more complex.

How political divisions shape sustainability discourse

Sustainability has become a political flashpoint, with issues such as climate change and diversity, equity and inclusion (DEI) facing growing opposition from anti-ESG movements, social media campaigns and legislative pushback. 

According to the report, 31% of CSOs identified increased politicisation as one of the biggest shifts in their role over the past two years.

Despite this, most CSOs remain undeterred. A striking 90% of those surveyed said they are staying committed to their sustainability work, even as some companies reduce external communications to avoid controversy. 

This aligns with the growing trend of 'greenhushing' — where firms downplay or under-report sustainability initiatives to avoid public scrutiny.

One respondent noted: “We are taking enhanced care and diligence on external disclosures and communications to consider how [messages] will be received and responded to across stakeholder groups.”

The challenge for CSOs moving forward is balancing transparency with reputational risk. While sustainability remains a core business imperative, navigating the external landscape is requiring a more strategic approach to messaging and stakeholder engagement.

Gender diversity rises, but racial diversity declines

The report also highlights a shift in the demographic composition of CSOs. 

While the percentage of women in CSO roles has reached an all-time high of 65% in 2025, racial diversity is moving in the opposite direction. 

The proportion of non-white CSOs peaked at 26% in 2023 but has since declined by 6%.

This trend coincides with a broader corporate retreat from DEI initiatives in response to political and legal pressures.

Sustainability must prove its business value

Beyond regulation and politics, the 2025 CSO Report reinforces a crucial trend: sustainability must align with core business strategies. 

Nearly half of CSOs (44%) said that integrating sustainability into overall corporate strategy was one of the most significant changes in their role since 2023. 

A growing focus on Scope 3 emissions — those generated by supply chains and product use — further highlights the business-critical nature of sustainability.

SAP’s Chief Sustainability and Commercial Officer, Sophia Lenora Mendelsohn, noted that sustainability is no longer just about compliance or reputation — it is becoming a financial driver.

“We have been talking about business transformation for a very long time. Now we are owning our own P&L and contributing to our colleagues’ P&Ls.”

CSOs are increasingly being asked to demonstrate how sustainable initiatives create economic value, whether through efficiency gains, risk mitigation or new revenue streams. 

This marks a clear evolution of the role of CSR oversight to a more integral business function.

What does 2025 hold for CSOs?

“CSO leadership is like Aikido,” says Dave Stangis, Partner and CSO of Apollo Global Management.

“It takes the right mix of art and science. Ten years ago, the CSO needed a 50/50 split to establish the position. 

“These days, the demands of the role have shifted to more like 75% art and 25% science.”

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