Future London Climate Risks Set Out

12 July 2016: The Committee on Climate Change (CCC) Adaptation Sub Committee (ASC) published a major new study today providing a detailed scientific assessment of climate change risks to UK. Further information is provided in the following press release, a summary synthesis report, which also links to the individual six sector chapters – which includes a chapter on ‘People and the Built Environment‘ (which is examined below)..

Below is a summary of some of the points most relevant to London from the synthesis report:

  • Urban water management: climate change is expected to lead to significant increases in heavy rainfall, with sewers in many urban areas already at or over capacity. More action is needed protect individual properties whilst also beginning to redesign urban landscapes (such as through the use of sustainable drainage approaches) to be able to cope with more intense patterns of rainfall. [p32]
  • At present, there are no comprehensive policies in place to adapt existing homes and other buildings to high temperatures, manage urban heat islands, nor safeguard new homes. The level of risk from overheating across the UK is unknown for hospitals, care homes, schools, prisons, and places of work. [p33]
  • The urban heat island effect. UK planning strategies do not currently make specific recommendations for reducing the heat island effect such as through planning and urban design, beyond promoting urban green space. [p34]
  • More action needed to deliver sustainable drainage systems, upgrade sewers where appropriate, and tackle drivers of increasing surface runoff (e.g. impermeable surfacing in urban areas). [p61]
  • Climate-related hazards damage historic structures and sites now, but there is a lack of information on the scale of current and future risks, including for historic urban green spaces and gardens as well as structures.[p66]
  • The action underway in London to assess and manage risks of overheating on public transport should continue, together with similar action as needed elsewhere in the UK. [p66]

The ‘People and the Built Environment chapter highlights a number of significant challenges that London could may face as a result of increasing temperatures as a result of climate change. These include:

  • The London Urban Heat Island (UHI) is generally found to be greater than those of other UK cities.
  • A study of 36 London dwellings during a hot spell in 2009  found that 15 out of 36 monitored bedrooms experienced night-time indoor temperatures above 26°C for more than 1% of the time
  • …by the 2030s, 59 – 76% of flats and 24 – 29% of detached properties in London could experience overheating (defined as internal temperatures > 28°C) during a heatwave event (high emission scenario). For the 2050s, the values increase to 80 – 92% of flats and 56 – 61% of detached dwellings (high emission scenario, median result).
  • Underground trains, especially those operating in the ‘deeper’ underground lines in London (e.g. Central and Bakerloo Lines), are vulnerable to overheating in prolonged hot weather
  • Transport for London scored overheating as one of the two highest risks to tube services in its second Adaptation Reporting Power report, along with flooding. Under the ‘Cooling the Tube’ programme, future tunnel temperatures have been modelled by Transport for London using the UK Climate Projections to test the effectiveness of different cooling strategies, though this work is not published. [NB TfL’s first adaptation report can be downloaded here]
  • It was reported in September 2015 that Transport for London planned to replace the non-opening windows on Routemaster buses to improve ventilation at a cost of £2 million
  • The transmission of vector-borne disease is also known to be affected by temperature….some vector species, such as the Ixodes ricinus tick that transmits Lyme disease, is already distributed throughout the UK. The Ixodes ricinus ticks are mostly encountered in the countryside, but are also present in urban parks: for example in South London.
  • Some potential vector species breed well in urban environments. Culex pipiens molestus is present in certain parts of London and in the London Underground system; it feeds readily on people and can transmit arboviruses. Culex pipiens breeds readily in water containers in urban gardens. While it rarely bites people, it feeds on birds and can contribute to the circulation of certain pathogenic viruses that affect people.
  • There is much uncertainty about how quickly populations can adapt to a warmer climate; however, the health burden of hot weather will be amplified by the ageing population in the UK. Health impacts are likely to be greatest in London, and increased in the southern, central and eastern regions of England.
  • Adverse cold effects on health have been observed in all regions in England, with the North East, North West and London having the greatest risk of cold-related mortality
  • Between 1970 and 1999, the onset of the birch pollen season in London has occurred earlier by four days every ten years. Some thunderstorms have been associated with increased hospital admissions for asthma exacerbations (‘thunderstorm asthma’).
  • In England, there are no longer performance measures for local government in relation to climate adaptation. There is variation amongst English local authorities in approach to adaptation with some having formal responsibilities (as in London through the Greater London Authority Act, 2007) and others having to work more informally, such as through the Core Cities group.
  • London has… a detailed flood management plan to the middle of the century and a strategic view beyond that based on adaptive management options and is currently considering responses to its draft urban drainage strategy.

BusinessGreen additionally reported that “By the middle of this century an average summer in London could see temperatures regularly hitting 38 degrees or more, while in the most extreme scenarios scientists have modelled temperature spikes as high as 48 degrees across the capital.” London has clearly much more to do when revising its climate adaptation plans.

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