Increased risk of extreme heat to European roads and railways with global warming
Eamonn Mulholland, Luc Feyen
Abstract
Changing climatic conditions pose a risk to existing transport infrastructures, which are generally built based on historical climate variations. When temperatures exceed built operating conditions, roads may require greater maintenance due to rutting, while railways are susceptible to buckling. We quantify the additional operation and maintenance (O&M) costs to railway and road infrastructures across the 27 Member States of the EU and the United Kingdom (EU + UK) due to the projected rise in extreme heat under different levels of global warming. Our risk assessment integrates an ensemble of climate projections under RCP4.5 and RCP8.5, a high-resolution spatial representation of the rail and road network, and asset valuation and maintenance information derived from multi-country databases, with a road pavement damage model and a railway buckling simulation model. Under a 4 °C global warming level, increased levels of extreme heat in EU + UK cause annual transport O&M costs to rise by €4.8 billion, corresponding to an overall 6.9% rise compared to current values. Mitigating emissions to comply with a 1.5 °C, 2 °C, and 3 °C rise in global average temperature limits the increase to €0.9 billion, €1.3 billion, and €2.8 billion, corresponding to O&M increases of 1.3%, 1.5%, 4.1% respectively. Depending on the value of the stock, replacement costs, and maintenance cycles in a country, the increase in risk can be much stronger. To pre-emptively limit risk, EU + UK road pavement construction standards and railway stress free temperatures should be updated to account for future changes in temperatures.