Health and climate change in EIA: what is 'significant' anyway?

The entry into force of the 2017 Environmental Impact Assessment (EIA) Regulations in England on May 16th has prompted a flurry of analysis, guidance, discussion and blogging on what it means to assess population, health and climate change within EIA. Not least at RPS, where we have been taking up this challenge on major energy, transport and other infrastructure projects in recent years.

The Institute of Environmental Management and Assessment (IEMA) has published two new short guides, on greenhouse gas emissions and health in EIA, and practitioners around the UK will be grappling with these topics: testing where to screen, how to scope, what impacts developers can or should mitigate; and gauging local planning authorities’ responses to these areas for more routine developments, which hitherto have been more a feature of Nationally Significant Infrastructure Projects (NSIP) scale applications.

Good practice for EIA in the UK rightly demands a high standard of evidence, with clear criteria and well-tested approaches to predicting impacts and effects. Equally, applicants and decision-makers alike recognise the importance of focusing on likely significant effects, to avoid deluging all parties in paper.

This all leads us to the crucial question, never quite settled: what actually is a ‘significant’ public health or climate change impact, anyway?

IEMA’s new guide to Green House Gas (GHG) emissions in EIA treads familiar ground, stating that all GHG emissions are significant, but suggesting that to determine just how much so, a practitioner can budget for a project’s emissions and compare these to (ideally science-based) global, national, sectoral or local carbon budgets – where available. In that last part lies the rub: the national carbon budgets for constituent countries of the UK are very broad tools to apply to an individual development, while the government stopped short of requiring carbon budgets to be developed at a local authority scale.

Alternatively, the guide offers examples of approaches that focus on the differences between mitigated and un-mitigated emissions, or difference to a business-as-usual baseline, which may risk losing sight of the importance of total net emissions.

Turning to health, there is an already well-recognised approach to Health Impact Assessment (HIA), together with a wealth of guidance on that topic. HIA seeks to be broad, participatory, and may have both quantitative and qualitative elements. It is a powerful tool (or rather a suite of tools), but its strengths lie perhaps more in its inclusiveness of all stakeholders and issues. Defining those ‘significant’ effects that an ES must communicate to decision-makers remains a challenge.

IEMA’s primer on health in EIA notes the need to develop a common language on what constitutes a significant population or human health effect, and leaves this as an exercise for future guidance.

In the meantime, there is a risk of falling back upon narrower assumptions that compliance with regulatory standards (demonstrated through EIA or permitting) precludes any health impacts, or adapting methods such as WebTAG which may not account fully for emerging scientific evidence or issues of particular community concern around a given project.

In the end, there is no simple definition of a significant impact in either of these areas, as the authors of various pieces of guidance have observed. But this does not mean that EIA practitioners should shy away from these topics, or assume absence of a clear threshold means there are no significant effects. Instead, it reinforces the role of the assessor’s expert professional judgement, borne of experience in these wide-ranging and rapidly evolving areas of evidence – which chimes well with the new EIA Regulations’ requirement that competent experts are employed.

Professional judgement can tell us whether a project’s climate impacts are out of step with industry trends, sectoral policy goals, or best practice for mitigating emissions; and where health impacts can be assessed quantitatively (increasingly the case for transport or energy schemes), an experienced public health practitioner can come to clear judgement on the magnitude of impacts relative to baseline health trends and the size of population affected, even where a single numerical threshold for significant effects cannot be justifiably set.

RPS will be staying at the forefront of this work, carrying forward the expertise built up through work for Hinkley Point C, Gatwick Airport and the M4 Corridor around Newport, among many other examples, to exciting new projects.