National and local policymakers need to wake up to the growing threats to lives and livelihoods that rising temperatures are causing in London and increase pre-emptive efforts to mitigate the worst impacts, writes Bob Ward.

Many of us look forward to warm summer days, but lives are already being lost in the capital and the economy is being hit by a lack of preparedness for more intense and frequent heatwaves. In particular, the Government’s approach to climate change adaptation and resilience has ignored the urgency and scale of the risks faced by London and other dense urban areas, especially in the South East.

These risks will be discussed today at a special event for London Climate Action Week 2023, co-hosted by the Grantham Research Institute and the London Climate Change Partnership, on ‘How should London cope with more summer heatwaves and wildfires?’

A heat-health alert was issued by the Met Office and the UK Health Security Agency ahead of a rise in temperatures in the capital over the weekend. It warned: “Significant impacts are possible across the health and social care sector due to the high temperatures, including: observed increase in mortality across the population likely, particularly in the 65+ age group or those with health conditions, but impacts may also be seen in younger age groups; increased demand for remote health care services likely; internal temperatures in care settings (hospitals and care homes) may exceed recommended threshold for clinical risk assessment; impact on ability of services to be delivered due to heat effects on workforce possible and many indoor environments likely to be overheating; risk to vulnerable people living independently in community as well as in care settings.”

Previous research has shown that deaths in London start to increase when the two-day average maximum temperature exceeds 24.8°C. Almost 400 deaths in London have been attributed to five periods of heatwave conditions last summer.

In addition, London experiences a significant, but largely unrecognised, hit to its economy during hot weather through cuts to productivity in overheating workplaces and failures of infrastructure. One recent estimate suggested that heat-related productivity losses in London could exceed £500 million each year.

London is particularly exposed to the effects of hot weather because of the urban heat island effect. The abundant dark man-made surfaces tend to absorb rather than reflect the sun’s radiation. As a result, London can warm by several degrees more than surrounding rural areas, and is the hottest place in the UK on average. Furthermore, the dense population of people working and living in London, and the infrastructure they use, makes the city a hotspot for heat-related risks. High levels of local air pollution from traffic and industrial activities, particularly on hot still days, can also add to the risks from heat. Climate change is significantly increasing these risks.

Too little focus on prevention

London, like the rest of the UK, is not prepared for the increase in the frequency and intensity of heatwaves. A recent survey by my colleague Dr Candice Howarth recorded a widespread view among experts that the UK’s authorities might not be able to cope if there is a repeat of last summer’s extreme temperatures, which topped 40°C in July. One of the main reasons for this critical situation is the Government’s focus on responding to the health consequences of heat instead of prevention.

The Government introduced a Heatwave Plan for England following extreme temperatures during summer 2003, which resulted in more than 2,000 domestic deaths and killed more than 70,000 across Europe. A review of the Heatwave Plan, which was published by the Policy Innovation and Evaluation Research Unit at the London School of Hygiene and Tropical Medicine in November 2019, identified several shortcomings. It concluded that “the general summertime relationships between temperature and mortality or emergency hospital admissions does not provide evidence that the introduction of the HWP [Heatwave Plan] in 2004 has had an effect on these outcomes”.

The review also pointed out that the heat-health alert system, operated by the Met Office and Public Health England (now the UK Health Security Agency), was failing to prevent deaths. It stated: “The health burdens associated with hot weather at temperatures below the alert thresholds set in the HWP, suggest that the current HWP is likely to make insufficient provision to prevent these outcomes.”

The Heatwave Plan for England was replaced this year by an Adverse Weather and Health Plan, and was accompanied by changes to the heat-health alert system so that it is now not solely based on breaching local temperature thresholds. However, this new plan still focuses on the health response rather than on prevention of the extreme heat conditions that threaten lives.

Statistical analyses of heatwave mortality, and other research, show that most of those who die are elderly and suffer from underlying health conditions, particularly respiratory illness. We know relatively little about the individual circumstances of those who die during heatwaves in the UK but previous research and analyses from other countries indicate that in heatwaves most people die inside overheating buildings, including hospitals and care homes. Heat in private homes is also a problem: a recent analysis by Arup for the Climate Change Committee found that “half of UK homes suffer from overheating risk”, and pointed out: “The risk is particularly high in the south of England, with London being the hottest spot in the country, and a moderate problem is present in the Midlands and Wales under current weather conditions.”

The Government has been very slow to recognise the risk of overheating in offices and homes. It amended building regulations to force developers to consider overheating risks only last year but the updated regulations do not go as far as the “cooling hierarchy” of actions to mitigate overheating in buildings promoted by the Mayor of London in the London Plan. The most recent assessment by the Climate Change Committee (CCC) of adaptation to climate change, published in March, acknowledged the update to building regulations as a step forward but pointed out gaps in the Government’s overall approach to tackling the risks of overheating. It stated: “There remains a lack of policy to address overheating in existing homes and buildings and a lack of understanding of the scale of efforts needed to mitigate the risk today.”

The CCC also warned that the changing climate is making these risks more urgent: “Averaged across the UK, the warmest temperature of the year has increased to around 27ºC from around 25ºC in the 1960s, with much more rapid rates of increase in South East England. The average duration of heatwaves (periods in which there are more than three days in excess of 25ºC) has increased over time.”

Time for a joined-up approach

The Government’s current approach to tackling the heat challenge is largely limited to the Department of Health and Social Care, while other relevant departments, particularly the Department for Levelling Up, Housing & Communities and the Department for Transport, seem to be largely ignoring the risks. It now needs to introduce an integrated and joined-up, cross-departmental approach to preventing the damage to lives and livelihoods from heat, particularly in London.

This kind of approach could take the form of a National Heat Risk Strategy, which I outlined in a letter to Boris Johnson, the then Prime Minister, in August 2020. The strategy should be announced in the forthcoming Third National Adaptation Programme, which is expected this summer from the Department for Environment, Food and Rural Affairs – the part of government that is supposed to lead on climate change resilience. The previous version of the Programme, published by Defra in 2018, was recently assessed by the CCC, which bluntly concluded: “The second National Adaptation Programme has not adequately prepared the UK for climate change.” This failure has led to the loss of lives and livelihoods in London and across the UK that could have been prevented. The new Programme must do much better.

Bob Ward is policy and communications director at the Grantham Research Institute on Climate Change and the Environment at the London School of Economics and Political Science, and chair of the London Climate Change Partnership.

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