There are three levels of risk assessment for climate change.

• A first‑pass climate change risk screening is a qualitative, low‑data assessment used to build an initial understanding of how climate change may affect an organisation.
• A second‑pass risk assessment is a more detailed, structured analysis that builds on the broad insights gained during a first‑pass screening. Its purpose is to examine the climate‑related risks that were initially flagged as important and assess them in a more systematic and evidence‑based way.
• A third‑pass risk assessment is a detailed, data‑heavy, usually professionally guided evaluation used when you need exact, site‑specific climate change risk information—usually for high‑risk or critical systems/assets require precise information to support engineering design, major investment decisions, or detailed implementation planning.

A first‑pass climate change risk assessment is a qualitative assessment that can be completed without detailed local data. Its purpose is to develop an initial understanding of how climate change could affect your organisation.

This type of assessment (sometimes called screening) is relatively low‑cost and enables users to gauge broad, high‑level risks by drawing on existing national, state or local information, as well as expert insights.

Broadly, a first-pass assessment aims to create a clear link to adaptation planning by highlighting priority risks, helping organisations focus their detailed assessments and adaptation measures where they’re most needed.

More specifically, a first‑pass climate change risk assessment can:

1. Provide a rapid starting point for understanding broad climate change risks to an organisation.
2. Clarify the inherent uncertainties related to the timing, location and magnitude of climate change impacts.
3. Identify climate‑related hazards that may disrupt business operations and highlight specific risks that warrant deeper investigation.
4. Pinpoint priority areas of operations (such as assets, services, regions or sectors) that require a more detailed (second‑pass) risk assessment to support effective adaptation planning.
5. Help determine which stakeholders need to be involved in the next stage of assessment.
6. Support engagement with decision‑makers by providing an evidence‑based foundation for securing resources, gaining organisational support and motivating leadership action.

First‑pass risk assessments are useful to understand the broader climate‑related risks of your organisation. However, they rely mainly on qualitative information and limited data, they can sometimes raise concerns for practitioners about precision and completeness.

These assessments are best used to frame and scope subsequent adaptation planning and risk assessments, rather than to inform final adaptation decisions.

By identifying where further assessment is actually needed, they help organisations avoid investing unnecessary time and resources in costly detailed second‑ or third‑pass analyses before they are needed.

This ensures that adaptation efforts are focused where they will have the greatest impact and avoids moving into technical detail prematurely, which can be both costly and inefficient.

Using the knowledge gained through a first-pass risk assessment and overall understanding of the adaptation planning cycle, a second-pass assessment can focus on specific sectors, areas or aspects that were identified as being at-risk.

A second-pass assessment can be undertaken using national data products and relevant local information from any previous studies and reports. Importantly, it can be used in combination with local expert knowledge to identify the likelihood of a given climate change risk and its consequence.

Building on the knowledge and insights gained from a first‑pass risk screening and a broad understanding of the adaptation planning cycle, a second‑pass assessment can take a closer look at the specific sectors, locations, or issues identified as being at risk.

This second pass assessment draws on national datasets as well as relevant local information from previous studies or reports. Importantly, it incorporates local expert knowledge to assess both the likelihood and the potential consequences of each climate‑related risk.

Many organisations already use structured, risk‑based frameworks to identify and manage operational and strategic risks. In the context of climate change, this approach aligns well with the principles of ISO 31000:2018, which emphasises a systematic, transparent, and iterative risk management process.

Integrating climate considerations into existing frameworks allows organisations to use familiar terminology and decision‑making structures while expanding their scope to include the unique characteristics of climate‑related risks.

Under the IPCC AR6 framework, climate risk arises from the interplay of hazards, exposure, and vulnerability, with risks increasingly shaped by compound events, cascading impacts, and systemic interactions across sectors.

A second-pass risk assessment therefore draws on national, state, and regional datasets, complemented by local studies and expert knowledge, to both estimate likelihoods and consequences as well as to understand how risks may evolve under different climate futures.

This approach supports a richer evaluation of risk by considering both present‑day impacts and projected changes.

Second‑pass risk assessments provide a more structured and detailed examination of climate‑related risks, but they still face important limitations.

They depend on national datasets combined with whatever local studies or expert knowledge are available, therefore precision of their findings are limited by the quality and completeness of this information or expert knowledge.

Because they require much more details, more evidence and expert knowledge is required, making this more expensive in terms of funds and capacity.

While a second pass risk assessment offers a stronger evidence base than first‑pass screenings, they are still not detailed enough to inform final adaptation decisions for significant or long term infrastructure, land-use planning or important cultural or ecosystems.

Instead, second‑pass assessments are most effective for refining understanding of risk, guiding discussions with stakeholders, and determining where deeper technical analysis is really needed.

By highlighting gaps in data and areas of uncertainty, they help organisations target their investment in more specialised third‑pass studies, ensuring that detailed assessment efforts are reserved for issues where they will provide the most value and avoid prematurely committing resources to highly technical work.

A third‑pass (detailed) climate change risk assessment builds on the previous two levels to provide a deep, site‑specific understanding of climate‑related risks, drawing on advanced modelling, high‑resolution datasets, and expert input.

It requires substantial data, specialised tools, and significant resources, therefore you should first determine whether this level of detail is necessary, typically after completing first‑ and second‑pass assessments

This level of assessment is especially valuable for complex or engineering‑focused projects - such as seawalls, groynes, and beach nourishment - where precise estimates of future change, including erosion, inundation, and sea‑level rise thresholds, are needed to inform design or major investment decisions.

It also incorporates contemporary adaptation approaches such as hazard–exposure–vulnerability analysis and time‑dependent pathways, reflecting improved understanding of evolving coastal risks and system interdependencies.

A third‑pass assessment provides a more advanced level of analysis using a standard risk‑based approach, that integrates both quantitative modelling and qualitative stakeholder input such as setting evaluation criteria and determining the relative importance of risks.

Third‑pass assessments can be used to explore time‑dependent vulnerabilities, identify risk thresholds, and develop adaptive pathways that respond to uncertain future conditions.

This deeper analysis may include high‑resolution erosion or inundation modelling, assessment of exposure and vulnerability, and identification of critical assets, interdependencies, and trigger points for when action is required.

A third‑pass assessment can be highly resource‑intensive: it usually requires commissioning more detailed data sets, use of specialist experts or consultants.

It increases the precision of risk estimates but not necessarily their accuracy due to uncertainties in climate and sea‑level rise projections.

Many organisations - especially smaller councils or businesses - typically lack the internal capacity to undertake such detailed studies without external support such as specialised consultants.