Overarching Context
Climate Change
Since the industrial revolution, atmospheric concentrations of GHG’s have increased rapidly compared to their pre-industrial levels, which has led to changes in Earth’s climate. As the rate of infrared radiation being absorbed into the Earth’s atmosphere increases, the Earth’s average surface temperature rises. These human-induced temperature increases are commonly referred to as global warming.
Absolute temperatures vary depending on your location in the world. Therefore, average global temperatures are assessed against a set baseline period of 30 years. Using surface temperature monitoring stations around the world to record changes in global temperature, variations in global temperature from this 30-year baseline can then be seen as a temperature anomaly.
Climate change is defined as large-scale, long-term shifts in the planet's weather patterns and average temperatures. The shift in global temperatures is already having a profound impact on Scotland. We have seen temperatures rise, sea levels increase and variations in rainfall, with extended seasonality.
Scientific analysis can also predict future changes. The magnitude of these changes carries uncertainties and vary according to different scenarios for global emissions pathways, but in any case, will be far greater than anything we have seen in the past.
United Kingdom Climate Projections (UKCP18)
The UKCP18 dataset is based on the latest developments in international climate science. They consist of:
- Updated probabilistic projections, giving estimates of different future climate outcomes;
- A new set of global climate model projections, comprising simulations from both the latest Met Office Hadley Centre climate model and global climate models from around the world; and,
- A set of regional climate model projections on a finer scale (12km) for the UK and Europe.
The UKCP18 aim to equip governments, businesses and other interested parties
with scientific information allowing them to assess the challenges and opportunities faced by our changing climate.
The key expected future climate change trends for Scotland, derived from the UKCP18 analysis, are identified in Figure 3 below.
Figure 3 - Scotland's changing climate, key trends and projections. (Source: Adapted from Adaptation Scotland, Climate Trends and Projections, 2021)
How has Scotland's climate changed?
Over the last few decades Scotland has experiences a warming trend, shifting rainfall patterns and rising sea levels.
- Scotland's 10 warmest years on record have all occurred since 1997. The average temperature in the last decade 2010-2019 was 0.69*c warmer than the 1961-1990 average, and the warmest year on record was 2014.
- There has been an increase in rainfall over Scotland over the past few decades (with an increasing proportion of rainfall coming from heavy rainfall events). The annual average rainfall in the last decade (2010-2019) was 9% wetter than the 1961-1990 average, with winters 19% wetter.
- Mean sea kevel around the UK has risen by approximately 1.4mm/year from the start of the 20th century.
How will Scotland's climate change in the future?
The changes in climate that we are already experiencing are projected to continue and intensify.
Summer
Scotland will experience warmer, wetter winters with more intense rainfalls.
- Although temperatures are expected to increase in both the summer and winter, warming is expected to be greatest in the summer
- Climate change has already increased the chance of seeing a summer as hot as the summer of 2018 to between 12 and 25%. With future warming, hot summers by mid-century could become even more common. near to 50%.
- Summer rainfall is projected to decrease, although extreme downpours will be heavier despite the overall drying trend.
Winter
Scotland will experience warmer wetter winters with more intense rainfall events.
- Winter temperatures are projected to increase.
- Winters are projected to become wetter in terms of both the amount of rainfall and the number of wet days. The increase is expected to be larger in western Scotland compared to the east.
- These changes do not mean that cold snaps and/or severe snowstorms can't or won't occur in the future.
Scotland’s Climate Risk
The UK Climate Change Act (2008) requires the UK Government (UKG) to conduct a UK-wide “Climate Change Risk Assessment” (CCRA) every five years. The latest suite of reports (CCRA3) identify and provide full analysis of 61 climate change risks and opportunities.
Four national summaries provide an overview of the CCC’s underpinning evidence for each of the UK nations. A series of sector briefings are also produced, including transport.
The CCRA3 assigns each risk or opportunity with an urgency score (Annex B) which indicates the level of action required based on current and planned levels of activity. These are:
- More Action Needed;
- Further Investigation;
- Sustain Current Action; and,
- Watching Brief.
Key risks from the CCRA3 in relation to Scotland and transport that have a high future magnitude score, and where more action is required now to address them after considering any existing adaptation responses, include the following:
- The risk of climate change impacts, especially more frequent flooding and coastal erosion, causing damage to our infrastructure services, including energy, transport, water and Information and Communication Technologies (ICT);
- The impact of extreme temperatures, high winds and lightning on the transport network;
- Increased severity and frequency of flooding of homes, communities and businesses; and,
- The viability of coastal communities and the impact on coastal businesses due to sea level rise, coastal flooding and erosion.
The CCRA3 has established that there are 32 risks/opportunities for Scotland that are categorised as ‘more action needed,’ with ‘sustain current action’ only applicable to four. Urgency scores have increased for 25 risk/opportunities in Scotland since CCRA2 in 2017.
Alongside the 61 individual climate risks and opportunities, the CCC also set out 8 priority risk areas for further adaptation within the next 2 years, covering various policy areas, including transport infrastructure. These are shown in Figure 4. Although there are not any specific areas for transport infrastructure there are clear links to certain priority risks area such as:
- Risks to the supply of food, goods and vital services due to climate-related collapse of supply chains and distribution networks; and
- Risks to people and the economy from climate-related failure of the power system
The figure shows the changing magnitude over time of the risk areas identified by the UK Committee on Climate Change that require the most urgent action in the next 2 years. The coloured lines signify the magnitude of risk, those which have more yellow are a medium risk:
- Risks to soil health from increased flooding and drought
- Risks to natural carbon stores and sequestration from multiple hazards leading to increased emissions
- Risks to crops, livestock and commercial trees from multiple hazards
- Risks to supply of food, goods and vital services due to climate-related collapse of supply chains and distribution networks
and those which have more red have a higher risk:
- Risks to viability and diversity of terrestrial and freshwater habitats and species from multiple hazards
- Risks to people and the economy from climate-related failure of the power system
- Risks to human health, wellbeing and productivity from increased exposure to heat in homes and other buildings
- Multiple risks to the UK from climate change impacts overseas
Transport Climate Risks
The CCRA3 identifies 7 key climate risks that relate to transport infrastructure, shown in Table 1 and in more detail in Annex C. The most significant weather-related risk facing Scotland is flooding and its impacts on people, communities, buildings and infrastructure. Although the CCC does not identify flooding as high priority risk area, the Scottish Government consider it as the most significant risk in Scotland and are therefore treating it as a priority.
The transport system and its networks regularly face challenges from weather related impacts (such as flooding, landslides and high winds), which as a result of climate change are projected to increase. There is a need for additional adaptation and resilience measures to avoid an increase in costly disruption and loss of service on transport networks.
Risks to infrastructure networks from cascading failures are an important aspect here that need to be managed due to the interdependencies between transport and other infrastructure networks, such as energy and water. For example, the loss of power supply may result in freight and travel delays across the transport network. Further, the CCC highlight that a “full understanding of the impacts of cascading failures is difficult to ascertain,” therefore it will be important that TS seeks opportunities to build resilience across wider infrastructure networks.
The long lifespan of transport infrastructure assets in relation to these risks must be considered for new and existing infrastructure across the entire transport system. This will be important as Scotland also moves toward Net Zero emissions by 2045, presenting an opportunity to build adaptive capacity and resilience into future infrastructure.
| CCRA3 Risk Identifier | CCRA3 Risk | CCRA3 Urgency Score |
|---|---|---|
| I1 | Risks to infrastructure networks (water, energy, transport, ICT) from cascading failures | More Action Needed |
| I2 | Risks to infrastructure services from river, surface water and groundwater flooding | More Action Needed |
| I3 | Risks to infrastructure services from coastal flooding and erosion | Further Investigation |
| I4 | Risks to bridges and pipelines from flooding and erosion | Further Investigation |
| I5 | Risks to transport networks from slope and embankment failure | More Action Needed |
| I7 | Risks to subterranean and surface infrastructure from subsidence | Further Investigation |
| I12 | Risks to transport from high and low temperatures, high winds, lightning | More Action Needed |
The Scottish Government is seeking to end Scotland’s contributions to the causes of global climate change through its commitment to Net Zero GHG emissions by 2045. The Climate Change Plan Update (CCPu) outlines strategic actions that will be taken to achieve this over the period to 2032, including various actions for transport that align with NTS2.
Alongside this, the second Scottish Climate Change Adaptation Programme (SCCAP2) set out the strategic approach to climate adaptation and resilience across all sectors of the economy (in response to the 2017 CCRA). The next SCCAP, in response to the 2022 CCRA, is due for publication in 2024. A hierarchy of key documents that include climate change considerations (both adaptation and mitigation) in relation to the transport system is shown in Figure 5.
Figure 5 - Hierarchy of Scottish Government climate change Plans and Programmes and key Transport Scotland Strategies that relate to climate change adaptation
SG Climate Change Plans and Programmes
Key TS Strategies
Key TS Supporting Documents
- NTS2 Delivery Plans
- STPR2 Supporting Documents
As noted previously, further climatic changes are projected and seen as inevitable. Preparations for these changes through mitigation, adaptation and resilience measures are therefore required.
Mitigation relates to reducing and/or preventing GHG emissions, thereby reducing the scale of future impacts as far as possible.
Adaptation is preparing for the impacts of climate change which are locked-in.
Resilience is the ability to respond to the weather-related impacts of climate change and maintain normal operation of a system and its associated services.
Although climate science and projections deliver a level of confidence in the general trends for future climate, there is no way of predicting an exact level of change, or precisely what the impacts will be. As a result, there will be some uncertainty over the ‘ideal’ level of adaptation and resilience planning that is needed. However, recent advice from the CCC suggests we need to adapt for 2 degrees of warming globally and in the face of future uncertainties, plan for 4 degrees. We must therefore take a flexible approach in relation to decision-making and lessons learned.
The Strategic Outcomes and Sub-Outcomes identified in this document represent the best options for the level of influence TS has over the transport system, its networks and infrastructure. The aim of the Strategic and Sub-Outcomes is to build capacity, appropriate adaptation and levels of resilience around current and future climatic events.
SCCAP2: Climate Ready Scotland
The Scottish Government’s second Climate Change Adaptation Programme (SCCAP2) is entitled Climate Ready Scotland. The programme runs until 2024 and sets out policies and proposals to increase the capacity of Scotland to adapt to climate change, based on the 2017 CCRA. SCCAP2 takes an outcomes-based approach (Figure 6) which is aligned with both the UN Sustainable Development Goals and Scotland’s National Performance Framework. An outcomes-based approach seeks to focus on what a policy or policies should achieve (the outcome), rather than the specific inputs and outputs.
TS leads on 13 SCCAP2 policy objectives, which aim to assist delivery of the programme (Annex D). These objectives are spread across various areas of transport. There is a focus on the delivery of actions that improve transport resilience, particularly across Trunk Roads, which feed into delivering the high-level outcomes of the programme.
In March 2022, the CCC published their first independent assessment of progress against SCCAP2, finding that whilst the vision for a well-adapted Scotland set out in SCCAP2 is welcome, progress towards this has “stalled across most sectors.” It was somewhat critical of transport areas, such as roads, ports and ferries, although acknowledged that this can be improved with the publication and delivery of this Strategy. The report did highlight good progress in adaptation planning in some areas, such as within the rail network and made a number of recommendations for driving forward adaptation which will be fully considered in delivery of our Strategic Outcomes outlined below.
Figure 6 - Outcomes of Climate Ready Scotland: Scotland’s second climate change adaptation programme 2019-2024
- Outcome one: Our communities are inclusive, empowered, resilient and safe in response to the changing climate
- Outcome two: The people in Scotland who are most vulnerable to climate change are able to adapt and climate justice is embedded in climate change adaptation policy
- Outcome three: Our inclusive and sustainable economy is flexible, adaptable and responsive to the changing climate
- Outcome four: Our society's supporting systems are resilient to climate change
- Outcome five: Our natural environment is valued, enjoyed, protected and enhanced and has increased resilience to climate change
- Outcome six: Our coastal and marine environment is valued, enjoyed, protected and enhanced and has increased resilience to climate change
- Outcome seven: Our international networks are adaptable to climate change
National Transport Strategy
TS’s NTS2 sets out the ambitions for Scotland’s transport system over the next 20 years. Through the priority ‘Takes climate action,’ it is envisaged that people will be able to make travel choices that minimise the long-term impacts on our climate and the wellbeing of future generations. It states that Scotland’s transport system will ‘adapt to the effects of climate change’ and deliver policies which will focus on Scotland’s transport networks to ensure they are managed effectively, well adapted and resilient.
The NTS2 Delivery Plan 2022-23 sets out a number of strategic policies including publishing Transport Scotland's Approach to Adaptation and Resilience (this document).
Following publication, we have continued to develop and enhance good adaptation practices across the agency, including the establishment of both a Vulnerable Locations Group (VLG) and Vulnerable Locations Operations Group (VLOG) for Trunk Roads.
Strategic Transport Projects Review
The second Strategic Transport Projects Review (STPR2) is a Scotland-wide review of the strategic transport system and networks, across all modes, and will inform transport investment in Scotland for the next 20 years. Options identified through STPR2 will focus on making the best use of existing capacity and assets.
STPR2 sets out a number of recommendations including several under the theme ‘increasing safety and resilience on the strategic transport network’, and one specifically for ‘Trunk Road and Motorway Network Climate Change Adaptation and Resilience.’