Extreme weather and EIA

This year has seen the hottest June on record in the UK, and a multitude of extreme weather-related events and records have been broken globally in the last few years. As I write this (July 2023) Europe is sweltering in the Cerberus heatwave, with record temperatures expecting to be broken in a number of locations.

As global temperatures increase due to climate change, this leads to an increased frequency of extreme weather events. In the past year we have seen extreme drought, wildfires and flooding events, to name a few, and these are likely to continue to increase in frequency and severity as global average temperatures continue to increase.

It is therefore essential that environmental professionals are equipped with the skills and knowledge to consider extreme weather events in their work. For new developments, ensuring that projects will be resilient to climate change and extreme weather will be vital for ensuring the longevity and safety of buildings and infrastructure.

To explore this topic the Environmental Impact Assessment (EIA) Community held a debate exploring extreme weather events in the UK, how they may change in the future and the ways in which environmental professionals can, or should, incorporate extreme weather into EIAs to ensure developments are fit for the future.

Extreme weather in the UK

Dr Jenny Pirrett from the Weather and Climate Extremes and Impacts Team at the Met Office provided a presentation on a selection of recent extreme weather events in the UK and explored how these events could change in future climate.

Watch the recording

EIA and extreme weather

Eleni Antoniades facilitated a workshop on extreme weather and EIA.

The EIA Directive has always included the requirement for EIA to “identify, describe and assess the direct and indirect effects of a project, which includes soil, water, air, climate and landscape”, as well as the requirement to assess the interactions between these different factors.

The EIA Directive was amended in 2017, reinforcing the need to assess climate impacts, including an addition for a requirement to describe the impact of the project on the climate, for example in terms of greenhouse gas assessment, and the potential impacts of the climate on the project itself. Climate risk assessments and flood risk assessments are also completed to feed into the EIA process, but there is no clear guidance on how extreme weather events should be considered in the EIA process beyond this.

Attendees at the event discussed how different extreme weather events could impact buildings and infrastructure and how they are and should be incorporated into EIAs.

Extreme weather will have myriad impacts on buildings and infrastructure

Extreme weather encompasses a wide variety of events including high winds, flooding, snowfall, heatwaves, wildfires, Saharan dust storms etc. They therefore present a number of risks to our buildings and infrastructure. This can vary from high winds impacting communication, to power and renewable energy generation (wind turbines often cannot function during periods of extreme wind). Snowfall has implications for load bearing on buildings and increased heatwaves present issues related to building and infrastructure design, such as the need for ventilation and the need for materials with high heat tolerance. Higher temperatures could also result in changes to atmospheric chemistry, which could have air quality implications such as the creation of more ozone at ground level.

The varied nature of extreme weather impacts and the potential for severe impacts indicates the need for these issues to be better explored during planning and development to ensure buildings and infrastructure are fit for the future.

There is no standard approach for considering extreme weather and climate change

Due to a lack of guidance around how climate change and extreme weather events should be considered in EIAs, there is no standard methodology for doing so. This has led to uncertainty in the process and varied approaches for how it is handled. For example, the issue can be integrated in other topic chapters, can be its own chapter, and sometimes can be in the appendices. It was noted that major infrastructure projects tend to incorporate these issues better than smaller projects, but even then certain topics tend to be better handled than others. Flooding is an example of an extreme weather event that is currently well-considered in the planning process. Other extreme weather events however, such as wind speeds and snowfall, are often scoped out of projects as they often have more localised and uncertain impacts.

Considering climate change and extreme weather at the design phase of a project is vital to ensure buildings and infrastructure are resilient to future weather and climate. Moreover, if Biodiversity Net Gain requirements are to be successful there should be some consideration of how embedded BNG actions are going to be resilient to extreme weather and climate change.

Further methodology is needed in a number of areas

There is a lot of uncertainty around extreme weather events and the potential impacts they can have. Examples raised include the effect that wind speeds can have on different infrastructure types, how extreme weather impacts geology and soils, how heat can impact things like Volatile Organic Compound (VOC) production etc.

Extreme weather event types also vary dramatically between regions at both the global and national scale. This means that tailored methodologies are needed for different environments and for different stages of planning and construction.

Construction impacts also need to be considered

Alongside the need for extreme weather impact assessment on projects once completed, extreme weather also needs to be taken into account for the construction phase of projects and potential impacts they may pose. For example, extreme weather can have many repercussions on construction, from droughts affecting water abstraction, to higher rainfall leading to landslides and posing health and safety impacts on site.

Next steps

The event underlined the need for further discussion and exploration of how extreme weather should be considered in the planning and construction of buildings and infrastructure, and the need for further guidance in this space.

The range and severity of extreme weather events merits the need for greater consideration in the planning and construction process and raises the question of whether a further assessment is needed beyond EIA to support this.

What is clear is that to ensure our buildings and infrastructure are resilient in the face of climate projections, we must collaborate and work across project teams. We must breakdown the siloes between EIA professionals, design teams and those working in construction, to embed better design from the outset to allow for better outcomes for people and nature.

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