Climate Change
UK Climate Projections 2018
Released in November 2018, UK Climate Projections 2018 (UKCP18)[1] build on previous UKCP09 projections to deliver climate projections data and tools designed to help UK decision-makers assess their exposure and vulnerability to climate change. UKCP18 is a climate analysis tool that forms part of the Met Office Hadley Centre Climate Programme.As with the previous UKCP09 projections, UKCP18 uses cutting-edge climate science to provide observations and climate change projections to 2100 for the UK and globally. UKCP18 provides the most up-to-date assessment of how the climate may change over the 21st century.
UKCP18 uses a range of possible future emissions scenarios, called Representative Concentration Pathways (RCPs). RCPs are the emissions scenarios used in the Intergovernmental Panel on Climate Change’s latest 5th assessment report[2]. RCPs specify the concentrations of greenhouse gases that would result in target amounts of radiative forcing at the top of the atmosphere by 2100, relative to preindustrial levels. Four RCPs are used in UKCP18; RCP 2.6, RCP 4.5, RCP 6.0 and RCP 8.5. At present, RCP 8.5 is the most widely accepted and probable future emissions pathway, and is associated with a projected increase in global mean temperatures of 4.3°C by the end of the century (compared to climate averages for 1850-1990)[3].
Why is it relevant to the highways sector?
UKCP18 indicates that winters will become milder and wetter winters, and summers will become hotter and drier. There will also be increased seasonality in rainfall and an increase in the frequency of extreme weather events, such as heatwaves, prolonged dry spells, storms and heavy and prolonged precipitation events[4].A summary of the key projections for the UK considering the highest emissions scenario (RCP8.5 – which is the mostly commonly accepted future scenario at present) with a 50th percentile change is as follow (all compared to the 1981-2000 baseline period):
- Mean annual temperature is projected to increase by 0.8°C by the 2020s, 1.7°C by the 2050s, and 3.3°C by the 2080s.
- Mean winter precipitation is projected to increase by 4% by the 2020s, 7% by the 2050s, and 16% by the 2080s.
- Mean summer precipitation in the UK is projected to decrease by 5% by the 2020s, 15% by the 2050s, and 26% by the 2080s.
These changes have the potential to have increasingly significant impacts on the UK’s highways sector, through risks and impacts including:
- Material and asset deterioration due to high temperatures and increased variability in rainfall patters.
- Overheating of electrical equipment, such as information and communication systems.
- Health and safety risks to maintenance workers and road users.
- Longer vegetation growing seasons resulting in increased periods of tree/ branch fall risk and increased soft estate maintenance and management requirements.
- Flood risk on the network and damage to drainage systems with the potential for increased runoff from adjacent land contributing to surface water flooding.
- Increased slope instability as a result of prolonged/heavy precipitation and increased frequency of drought leading to subsidence.
- Inaccessible network during severe weather events.
[1] UK Climate Projections 2018. Available at: https://www.metoffice.gov.uk/research/collaboration/ukcp/about
[2] IPCC 5th Assessment Report. Available at: https://www.ipcc.ch/assessment-report/ar5/
[3] UKCP18 Guidance: UKCP18 for UKCP09 users. Available at: https://www.metoffice.gov.uk/binaries/content/assets/metofficegovuk/pdf/research/ukcp/ukcp18-guidance-ukcp18-for-ukcp09-users.pdf
[4] https://www.metoffice.gov.uk/binaries/content/assets/metofficegovuk/pdf/research/ukcp/ukcp18-overview-slidepack-notes.ff.pdf
[4] https://www.metoffice.gov.uk/binaries/content/assets/metofficegovuk/pdf/research/ukcp/ukcp18-overview-slidepack-notes.ff.pdf
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