A transport system that is prepared for extreme weather and the effects of future climate change is vital to London’s continued success. A reliable and effective infrastructure is not only important for commuters and tourists alike, but it is also critical for businesses and their supply network.
Heat stress and thermal comfort are likely to become an increasingly important issue under the changing climate, particularly during heatwaves. For much of the transport infrastructure, the impact on passengers should be minimal as air conditioning units are already becoming standard across modes.
One notable exception however is the London Underground system. Even in our present climate the Underground network can be uncomfortably hot in the summer, and during hot weather some sections of the network can reach temperatures that may affect the wellbeing of vulnerable passengers. As most of the London Underground was built before air-conditioning was invented, and the tunnels were designed with just enough room for the trains, cooling the London Underground network is a highly complex engineering problem.
In addition, London Underground is preparing to meet the rising demand by increasing passenger transport capacity on the network by 300,000 passengers a day by 2016, with longer and more frequent trains. Together these will increase temperatures in the network. London Underground has a cooling strategy for the network in place, which involves a mix of measures.
A programme of retrofitting existing buses with white painted roofs and automatic ventilation system is also underway to keep passengers cool.
Because it is densely populated and developed, London also needs to import a large percentage of its water, energy, workforce, food, and other consumables from outside of the city, making its supply chains more susceptible to disruption.
It is estimated that the number of days above the temperature threshold where cooling is required is set to rise significantly. While currently residential properties do not contribute significantly to cooling demand, they are likely to do so in future as we see hotter summers and more frequent heatwaves.
However, other factors such as household income and future housing design are also expected to play a large part in the uptake of domestic air conditioning.
Cooling demand from commercial properties is also expected to continue to rise. As well as contributing to the Urban Heat Island effect, the expected increase in use of air conditioning will have an impact on our summer energy use.
A positive aspect, however is that warmer winters are projected to reduce our winter energy demands.