Is the role of a Chief Sustainability Office still relevant, or waning before its even taken root? Oxford HR researcher and analyst Lionel Issombo shares his view.
In the past decade, many organisations around the world have pressed to adopt a much more socially and environmentally responsible stance, from their corporate structure to their external footprints. While concepts such as DEI and ESG were iconic parts of what defines corporate sustainability, the very meaning of leadership shifted gradually beyond reputation; it became action-oriented. Chief Sustainability Officers (CSOs) emerged as armorbearers of that ideal across the corporate ladder.
In recent years, however, there were rising speculations around the relevance of the CSO role, as the role was neither traditional nor fully understood or supported – this was also significantly affected by divisive opinions over the scope of the adoption of sustainability-linked policies and regulations, and how it may affect the structure of organisations and their markets (particularly for those in the U.S.). As a result, the number of CSOs at publicly listed U.S. firms dropped 10% from 216 in 2025 to 193 as of July 1, 2026.
As the US market is sending a clear signal that the CSO role may be overrated, is it truly the case? If not, then what keeps corporate CSO leadership relevant today?
CSO: The “Spider Net” of the C-Suite
To understand the relevance of the CSO role for a responsible organisation, it is first crucial to clarify that sustainability cannot survive in an isolated department; it must exist across and be embedded into procurement, legal, R&D, and HR. As many sustainability executives still lack ESG expertise, for instance, the CSO serves a critical bridge, translating complex environmental requirements into practical actions across the organisation. Clearly, if a rule is misunderstood, strategic coordination, decision-making, execution and market output produce poor results; and for many companies, this rapidly becomes a P&L (profit and loss) issue. With more than 97% of CSOs now reporting directly to the CEO or Board, their role has become central to connecting sustainability priorities with effective corporate strategy.
CSO: A Game-Changer to Firms Seeking Evidence-Based Claims
Since 2020 alone, companies including Shein, DWS, Eni and TotalEnergies have faced significant regulatory or legal consequences over sustainability and greenwashing concerns, ranging from €5 million and €25 million fines to €40 million and €22.4 million penalties. As earlier mentioned, this is where the CSO role serves as a critical bridge. While the market rules differ in the U.S., for instance, these repercussions are still affecting companies’ operations globally.
The reality is that global regulations are rapidly changing and corporate sustainability communication is entering a more scrutinised era. Growing anti-greenwashing requirements and greater stakeholder scepticism mean that ambitious environmental statements must be supported by evidence rather than marketing language alone. The CSO helps establish this discipline by linking sustainability commitments to reliable datasets, measurable performance indicators and demonstrating progress. This way, corporate claims become more credible, defensible and aligned with what the business is actually delivering.
CSO: A Regulatory Control Tower
Looking at the status of global economic rules today, sustainability reporting is leaning more toward a compulsory corporate exercise, and the voluntary frameworks are limited. With requirements such as the EU’s CSRD and IFRS S1 and S2 reshaping how climate-related and sustainability-related information is reported and scrutinised, companies need leadership capable of connecting environmental data with governance, risk and financial decision-making.
The CSO increasingly fulfils that role:
- Coordinating information across the organisation,
- strengthening the credibility of disclosures,
- and helping the business manage regulatory, legal and investor expectations.
CSO role may no longer be a leadership imperative for organisations in a restricted economy, but its relevance at the global level is evident. As sustainability becomes increasingly intertwined with regulation, risk management, operational resilience and investor expectations, the function is evolving rather than disappearing. For globally exposed organisations, this makes the CSO less of a standalone sustainability advocate and more of a strategic leader connecting environmental intelligence with business performance. The role may therefore become leaner in some markets, but its strategic value remains significant where regulatory, operational and reputational exposure is high.
Lionel Issombo
Lionel is a business intelligence professional with a focus on climate risk and adaptation in the banking and finance sectors. With a Master’s degree in Diplomacy and Foreign Policy, specialising in International Political Economy from Lancaster University, he offers a unique global systems perspective to his consulting work.
His extensive experience spans finance, development, and sustainability, having collaborated with leading organisations such as the Association for Financial Markets in Europe (AFME), Climate X, and 15Rock. At these institutions, Lionel has led research and analytical projects addressing climate stress testing, disclosure standards, and executive search.
Passionate of sustainable finance, climate risk management, adaptation and resilience, Lionel has effectively engaged with regulators, major banks, and consulting firms across Europe and North America, to shape the evolving landscape of leadership around climate risk management and adaptation investing.
