BCG generated $2.7 billion from AI-related advisory in 2024, a revenue stream that didn’t exist two years earlier (BCG, 2025). The consulting industry is growing faster than ever. The consultants who built it are being replaced.

What AI Actually Commoditised

The sustainability consulting industry was built on a specific economic model: clients paid for access to expertise they didn’t have in-house, delivered through labour-intensive processes. Benchmarking. Gap analyses. Materiality assessments. Framework mapping. Report drafting. These deliverables consumed thousands of hours and generated reliable revenue for firms of every size.

That model assumed information asymmetry. The consultant knew things the client didn’t. They had access to frameworks, peer data, and reporting standards that were difficult to navigate without specialist help. Harvard Business School’s study with 758 BCG consultants demonstrated the scale of what’s changed: for 18 realistic consulting tasks, consultants using GPT-4 completed 12.2% more tasks, 25.1% faster, at 40% higher quality (Dell’Acqua et al., 2023). The tasks that defined junior consulting work can now be performed in a fraction of the time, at a fraction of the cost, by a fraction of the team.

ICAEW found that AI can cut sustainability assessment time from four to six manual hours down to one (ICAEW, 2024). The World Economic Forum documented how AI now automates product-level carbon footprint calculations and real-time Scope 3 tracking across supply chains (WEF, 2025). 63% of companies are already using or planning to use AI for sustainability data collection, analysis, and reporting (Market.us, 2025). The work hasn’t disappeared. The willingness to pay a consultant to do it has.

The Structural Shift

Harvard Business Review described the transformation precisely. The traditional consulting “pyramid” model, a wide base of junior consultants supporting a narrow apex of senior leaders, is being replaced by a leaner “obelisk” with fewer layers and smaller teams (Duncan et al., 2025). AI handles the research, modelling, and analysis that once required the pyramid’s base. The firms that recognise this are restructuring. The ones that don’t are losing ground.

The numbers tell the story. McKinsey cut roughly 10% of its workforce, reducing headcount from over 45,000 to about 40,000, while deploying thousands of internal AI agents to automate work previously done by junior consultants (Fast Company, 2025). PwC’s internal projections show associate hiring falling 32% in tax and assurance and 39% in audit between 2025 and 2028 (Management Consulted / PwC, 2025). Professional services leads all sectors in generative AI adoption, with implementation rates increasing from 33% in 2023 to 71% in 2024 (Firmwise, 2025).

The sustainability consulting market specifically is growing. Source Global Research forecasts it will hit $54 billion in 2025, up from $51.2 billion in 2024 (Source Global Research, 2025). But the nature of what clients want is changing. Clients told Source that technology firms are their provider of choice for sustainability support. Over half of businesses that previously aimed to be sustainability leaders have scaled back their ambitions, with just 31% still targeting leadership and one in eight saying sustainability isn’t relevant to them at all (Source Global Research, 2025). Yet 77% plan to increase their investment in sustainability support. The demand is rising while the willingness to pay for traditional advisory is falling. Clients want faster results, technology-enabled delivery, and proof that spending on sustainability support produces measurable outcomes.

Three Things That Separate the Survivors

The consultants who remain valuable after AI commoditises research and content production share three characteristics. They’re structural, not cosmetic.

The first is proprietary data and technology. BCG’s survey of 1,250+ firms found that only 5% are achieving AI value at scale, while 60% report minimal gains despite substantial investment (BCG, 2025). The difference comes down to infrastructure. Companies with fully modernised, AI-led processes achieve 2.5x higher revenue growth and 2.4x greater productivity (Accenture, 2024). The same logic applies to consultancies. A firm with sector-specific benchmarking data, analytical models that connect sustainability factors to financial performance, and the ability to show clients exactly what investors and rating agencies weight in their industry can deliver insights that a generalist using off-the-shelf AI cannot replicate. The consulting firms investing heavily in proprietary AI capabilities are growing. Accenture invested $3 billion in AI and generated $4.1 billion in generative AI bookings, nearly doubling its AI workforce to 77,000 in two years (Accenture, 2024). The advantage lies in data and tools that clients can’t access elsewhere.

The second is speed that redefines delivery timelines. The traditional consulting engagement was measured in weeks or months. AI compresses that timeline to days or hours. Forrester articulated the paradox directly: consultants can use AI-powered delivery platforms to do more work at lower cost, which puts pressure on margins, reduces headcount needs, and forces a reconciliation between what buyers need and what providers have historically offered (Forrester, 2025). Simon-Kucher found that the predominant time-and-materials pricing model poses tremendous risk of revenue leakage, as tasks that previously took hours or days can now be done within minutes (Simon-Kucher, 2024). Time-and-materials revenues are expected to decline from 80% to 60% of total revenues. The consultants who survive will bill for outcomes, with pricing models tied to measurable client impact rather than hours logged.

The third is demonstrable, measurable client impact. McKinsey’s State of AI research found that 88% of organisations deploy AI in at least one function, but only 39% see any measurable effect on EBIT, and most of those report AI accounts for less than 5% of EBIT (McKinsey, 2025). The gap between AI adoption and AI value creation is enormous. The same gap exists in sustainability consulting. BCG’s analysis of more than 500 sustainability initiatives found that only 1 in 5 showed any meaningful connection to drivers of business value (BCG, 2022). The consultants who thrive will be the ones who can prove their work moved a metric that the CFO cares about: cost of capital, revenue growth, risk reduction, regulatory compliance achieved at lower cost. That proof requires before-and-after measurement against external benchmarks, not self-reported progress narratives. Activity reports won’t be enough.

What This Means for Sustainability Consultants

Gartner predicts that through 2026, atrophy of critical-thinking skills due to GenAI use will push 50% of global organisations to require AI-free skills assessments (Gartner, 2025). The Harvard Business School / BCG study found that consultants using AI on tasks outside the AI’s capability frontier performed 19 percentage points worse than those without AI access (Dell’Acqua et al., 2023). These findings point to the same conclusion: AI makes average consultants faster at routine tasks, but it makes differentiated expertise more valuable than ever.

The sustainability consultants who survive will look fundamentally different from the ones the industry trained over the past two decades. The generalist who could write a materiality assessment for any sector is being replaced by the specialist who understands three or four industries deeply enough to tell a client something the client’s own AI tools haven’t surfaced. The 200-page report on a 12-week timeline is giving way to actionable intelligence delivered in days, supported by technology that allows a three-person team to produce what used to require fifteen. And the metric that matters is shifting from hours billed to performance improvements verified against financial baselines.

Verdantix projects the sustainability consulting market will grow from $12 billion to nearly $30 billion by 2030 (Verdantix, 2024). But the firms capturing that growth won’t be the ones running the same engagement model with AI bolted on. Forrester is clear: new entrants with AI-first value propositions are putting pressure on established consultancies to revamp their approaches, and providers with scale and strong balance sheets will thrive while smaller or less nimble providers will struggle (Forrester, 2024).

The Question That Matters

The sustainability consulting market is getting larger. The number of consultants it can sustain at current economics is getting smaller. The World Economic Forum said it directly: AI will not replace sustainability professionals, but those who can harness AI effectively and responsibly will have a clear advantage (WEF, 2025).

If you’re a sustainability consultant today, the question has moved past whether AI will affect your practice. The question is whether you have something to offer that a well-prompted language model does not. If your value is research, benchmarking, and report writing, the answer is already clear. If your value is proprietary insight, speed that changes client decisions, and proof that your work improved a financial outcome, you’re in a market that’s about to get significantly larger and significantly less crowded.

Which of those two markets are you competing in?

References

• BCG (2025). “Are You Generating Value from AI? The Widening Gap.”
• Dell’Acqua, F. et al. (2023). “Navigating the Jagged Technological Frontier.” Harvard Business School Working Paper No. 24-013.
• ICAEW (2024). “How AI Is Blazing a Trail in ESG Reporting.”
• WEF (2025). “How AI Can Transform Sustainability Reporting.”
• Market.us (2025). “AI in ESG and Sustainability Market.”
• Duncan, D.S., Anderson, T. & Saviano, J. (2025). “AI Is Changing the Structure of Consulting Firms.” Harvard Business Review.
• Fast Company (2025). “Why the McKinsey Layoffs Are a Warning Signal for Consulting in the AI Age.”
• Management Consulted / PwC (2025). “PwC Entry-Level Recruiting to Slow.”
• Firmwise (2025). “AI in Professional Services: 2025 State of the Industry Report.”
• Source Global Research (2025). “The Sustainability Consulting Market in 2025.”
• Accenture (2024). “Reinventing Enterprise Operations with Gen AI.”
• Simon-Kucher (2024). “Generative AI and the Price Model Revolution in Professional Services.”
• Forrester (2025). “GenAI Disrupts Professional Services.”
• McKinsey (2025). “The State of AI: How Organizations Are Rewiring to Capture Value.”
• BCG (2022). “The Strategic Race to Sustainability.”
• Gartner (2025). “Strategic Predictions for 2026.”
• Verdantix (2024). “Market Size and Forecast: Sustainability Consulting 2024-2030.”
• Forrester (2024). “The Future of AI Consulting Services Is Disruptively Bright.”