CDP and assurance

Building trust through verified environmental reporting

Authors: Archie Putt, Assistant Manager, Consulting,

As environmental concerns continue to grow, organisations face pressure to disclose sustainability metrics transparently and credibly.

Political scrutiny, regulatory developments, and the growing risk of greenwashing claims have intensified the demand for accurate and trustworthy data. Yet, many organisations continue to struggle to produce reliable environmental disclosures, leading to unintended misstatements.

Stakeholders, such as investors, regulators, and customers, use the data to inform decisions. However, frequent restatements of emissions data, driven by evolving methodologies and improved data availability, can start to undermine stakeholder confidence. In response, both organisations and stakeholders are seeking ways to validate the credibility of environmental data.

One increasingly recognised benchmark for best practice in environmental reporting is the rating provided by CDP. A strong CDP score signals that an organisation is not only transparent but also committed to rigorous, high-quality environmental disclosure.

What is CDP and how is it a credibility benchmark?

CDP is an independent global environmental disclosure system for companies, capital markets, cities, states and regions to manage their environmental impacts. It promotes transparent reporting across environmental issues including climate change, waste management, biodiversity, and water use.

Organisations submit responses to CDP’s standardised questionnaire, which are scored publicly. To maximise efficiency with other regulatory and voluntary reporting, CDP is aligned with several international frameworks, including:

International Financial Reporting Standards (IFRS) S2 Climate-Related Disclosures
European Sustainability Reporting Standards (ESRS)
Task Force on Nature-Related and Climate-Related Financial Disclosures (TNFD and TCFD)

Achieving an “A”, the highest available score, is a strategic goal for many organisations because the rating is widely used to:

differentiate between leaders and laggards
inform investment and lending decisions
influence supply chain and partnership choices.

However, there are essential criteria that organisations must comply with to achieve an “A” score – one of which is obtaining independent assurance over their emissions data.

How does CDP score progress?

CDP’s scoring framework is designed to reflect the maturity of an organisation’s climate response and includes the following grades:

Disclosure (D)

Reflects organisations that report only foundational information.

Awareness (C)

Applies to organisations that have identified and assessed climate related impacts and risks, but have yet to translate this understanding into tangible actions to address the issues identified.

Management (B)

Awarded where respondents can demonstrate evidence of actions taken to manage and reduce their environmental impact, though these measures are not yet sufficiently comprehensive or embedded to be considered leading practice.

Leadership (A)

Reserved for organisations that have integrated environmental considerations into their strategy, governance, and decision making. These entities evidence robust, forward looking actions and represent best practice in managing their environmental impact.

Progress through these levels depends not only on the quantity of information disclosed but on the quality of evidence behind it – which is where assurance comes in.

What are CDP’s assurance expectations?

To achieve the top CDP score, organisations must verify their emissions data:

Scope 1 and 2: independent verification of 100% of scope 1 and 2 emissions
Scope 3: independent verification of one Scope 3 category, at a minimum, and the verification must cover at least 70% of all the reported scope 3 emissions.

CDP does not mandate a single standard assurance standard but expects adherence to recognised professional frameworks. In practice, this means:

using established international or national assurance and verification standards for sustainability and Greenhouse Gas (GHG) reporting. For example, this may include ISAE 3000, ISAE 3410 and soon to be adopted ISSA 5000
clearly defining the scope, the level of assurance (limited or reasonable) and the period covered
ensuring assurance is demonstrably independent from those responsible for preparing the data.

Timing and the CDP cycle

CDP follows an annual cycle and obtaining assurance must align with this reporting timetable.

Typically, the CDP cycle includes:

early year: methodology and guidance released by CDP
mid-year: the disclosure window opens
autumn: the scoring deadline (Wednesday 17 September in 2025).

For organisations, the implications are clear:

emissions for the relevant reporting year need to be calculated, reviewed and internally approved in good time
assurance must be completed before the scoring deadline
any issues identified during assurance must be resolved promptly to not jeopardise the outcome of the assurance report and thus the CDP scoring.

Next steps

Moving towards assurance can feel like a big step. Therefore, organisations may want to consider starting with a readiness assessment. Following the readiness assessment, most firms start with limited assurance over their GHG emissions, which supports both CDP submissions and statutory sustainability reporting, while creating a pathway to expand scope or move towards reasonable assurance over time.

Given the increasing breadth of stakeholder expectations, organisations may encounter requests for varying levels and types of assurance. Taking a coordinated and strategic approach to these needs can help ensure that all stakeholders are appropriately satisfied, while avoiding unnecessary duplication of effort. Adopting an efficient, consolidated assurance strategy enables organisations to meet diverse requirements in a way that is both proportionate and operationally streamlined.

How can Crowe help

We support organisations with independent GHG assurance across Scopes 1, 2, and 3 emissions – as well as other sustainability-related data. We recognise that assurance reduces regulatory, reputational, and operational risk as well as improving decision‑making internally.

Our approach is:

technically robust
aligned with evolving regulation and standards
efficient across multiple reporting requirements.

If your organisation would like assurance to support achieving the highest CDP rating or chat further about the benefits of assurance, please contact Alex Hindson, Lloyd Richards or your usual Crowe contact.