Filling the gaps: New research will help us to better understand UK climate risk

Next summer, the Committee on Climate Change (CCC) will publish its next national assessment of the risks and opportunities facing the UK from climate change.

The  Evidence Report – underpinned by input from over 130 organisations – will inform the Government’s official third UK Climate Change Risk Assessment (CCRA3), leading to new plans and policies to build the nation’s resilience as the climate changes.

It’s a huge task; evaluating our latest understanding of what climate change means for the UK takes years of work and will result in several thousand pages of analysis.

The first set of outputs from this ambitious research programme is now complete. Six independent research projects, published today, will help to fill priority gaps in knowledge and reflect the latest science. They are:

1. Projections of Future Flood Risk (led by Sayers and Partners)
2. Projections of Future Water Availability (led by HR Wallingford)
3. Understanding how behaviours can affect climate risk (led by AECOM)
4. Climate-driven threshold effects in the natural environment (led by UKCEH)
5. Interacting risks in infrastructure, the built and natural environments (led by WSP)
6. A supporting report to provide a consistent set of socioeconomic data for use by the CCRA analytical teams (led by Cambridge Econometrics)

These important new pieces of research have been commissioned by the CCC, and part-funded by Defra, governments in Scotland, Wales and Northern Ireland, and the Research Councils.

Each provides a wealth of new information and quantification of the various effects of climate change across different sectors. These quick summaries explain each project’s findings in a little more detail. Taken together, they run to hundreds of pages of new analysis, so each report also comes with a short, easy-to-read executive summary. 

Notably, the projects are among the first studies to make use of the Met Office’s latest set of UK climate projections, UKCP18, which make them some of the most up-to-date in terms of assessing the range of climate impacts coming down the track, and how those impacts may play out spatially across the UK. And they all demonstrate that a twin-track approach of adaptation and mitigation are essential if we are to manage the risks effectively. It’s important to stress that the research does not represent the CCC’s view at this stage – these are inputs into our assessment, and fully independent. Key findings include:

Future flood risk:

• Combined flood damage from coastal, surface water, river and groundwater will rise in the future in all of the scenarios studied, from an average estimated £2 billion worth of damage annually today. Only a combination of very strong action to reduce emissions (stabilising global temperatures at or below 2°C this century), combined with high adaptation action (meeting and going beyond current policy commitments to reduce flood risk) can keep the increase in damage to a low level (less than £2.5 billion annually) by the end of the century. Without these measures, expected annual damages could double.
• There are large spatial variations in future flood risk across the UK. Coastal and surface water risks are likely to rise faster than for river flooding, though the latter remains the dominant driver of flood risk by 2100. While England has the largest expected annual damage (because it’s the most populated of the four UK nations); Scotland, Wales and Northern Ireland are projected to experience larger flood damage per person, especially amongst the most socially vulnerable groups.

Future water availability:

• The UK is at risk from too little as well as too much water. In a low mitigation, low adaptation world (where emissions continue at today’s levels, and we fail to adapt effectively), the gap between supply and demand for public water supply grows to nearly 3 billion litres by the end of the century across the UK, with deficits concentrated in England given it has the largest population.  Stabilising temperatures at 2°C and investing in higher levels of adaptation can significantly reduce and even eliminate deficits across much of the UK. 
• As well as demand for the public water supply, water used for agriculture, energy generation and industry will continue to place pressures on natural water flows. Determining how much water is needed to ensure the health of the natural environment is key to the size and type of the risk that different catchments face.

Understanding how behaviours affect climate risk:

• People’s behaviour in response to extreme weather can be an important factor in understanding how well prepared populations are for climate change, but little evidence on this has been available until now. This project gathered evidence on people’s behaviours in different locations and in response to different hazards, as well as collating new evidence from the literature on how behaviour moderates risk.
• There are multiple barriers to taking impactful actions, the study showed, including limited awareness of the changing level of risk and a lack of information on the effectiveness of different adaptation measures. The research finds that the misconception that adaptation action only includes ‘hard’ structural or property adjustments could be deterring greater action; that much better data services are required; and that climate services e.g. local climate risk assessments, need to be tailored to acknowledge local experience and expertise.  
• Case studies were conducted in the Orkney Islands, Peebles and across Northern Ireland (in response to multiple extreme events) Manchester and Llechryd (flooding), and London (extreme heat). The analysis identifies over 80 different behaviours that can be taken by households, land managers or businesses to reduce risk.

Climate-driven threshold effects in the natural environment:

• This project aimed to gather new evidence on threshold effects (the point at which a ‘non-linear’ change in an ecosystem occurs as a result of change in a climate driver – such as temperature), for different land cover types; freshwater, farmland, peatlands, woodland and marine and coastal regions. Past CCRAs have considered threshold effects but have been unable to quantify them, so this project adds useful new quantification of these effects.
• The analysis found that all of the threshold effects considered are expected to increase in frequency and severity in the future, potentially leading to irreversible changes such as peatland loss, permanent loss of topsoil, species range shifts and loss of the economic viability of certain tree species. Economic damages vary from tens of millions to billions of pounds annually for each threshold.
• A range of adaptation options are available to manage these effects including reducing nutrient inputs from fertilisers to lakes and rivers, planting trees next to water courses for shading, rewetting of peatlands, considering climate-relevant genotypes or altered species in new woodland plantings, and moving to continuous cover forestry.

Interacting risks:

• A specific climate change impact (e.g. a flood) has knock-on effects that run through infrastructure, built and natural environments, but these effects have not been well-quantified to date. This final project aimed to provide additional analysis for use in the technical chapters of the Evidence Report about how different risks interact and what these interactions mean for the overall level of risk. 
• The study highlights that flooding, high summer temperatures, sea level rise, extreme rainfall and drought will lead to increasingly significant interactions of impacts in the future as they transfer through the sectors (e.g. built environment, natural environment). The total impact in a world that has warmed by 4°C by the 2080s through the various pathways modelled suggest a 20-fold increase in impacts compared to today.
• The natural environment is highly connected, suggesting that improvements to its resilience can have far-reaching benefits across all sectors.

Now that this independent research is complete, it will be used to inform the detailed climate risk evidence report which is being prepared by a consortium of experts, led by the University of Exeter. That in turn will inform the Committee’s final assessment.

Given the huge breadth and depth of information that needs to be collated and explained within the CCRA Evidence Report, a further project is also underway to ensure effective communication of the analysis and results to key decision-makers. The results of that project, can be viewed here.