Dr Alexander Waller (American University of Sovereign Nations)              HRSC0023

Written evidence submitted by Dr Alexander Waller

Evidence for the Environmental Audit Committee Heat resilience and sustainable cooling inquiry.

Alexander Waller PhD MSc BSc (Hons) CBiol FRSB CChem MRSC

Visiting Professor of Environmental Ethics, American University of Sovereign Nations

This opinion piece is a review of the current literature that is relevant to some of the questions in the terms of reference for the committee call for written evidence for the inquiry into heat resilience and sustainable cooling. This is framed within the context of the UNEP (2022) Emissions Gap report, which states that:

The energy that is used for heating, cooling and appliances per square metre of floor area, needs to decrease globally by 10–30 per cent in commercial buildings and 20–30 per cent in residential buildings, relative to 2015 levels, by 2030.

The same report prioritises that building thermal efficiency should be optimized and zero-emissions technology for heating and cooling should be scaled-up. However, technical solutions alone are not sufficient to reach a target of limiting global warming to 1.5oC, so this paper addresses some of both the social and technical dimensions (Eyre et al, 2018).

What evidence exists on the relationship between heat and human health (mortality and morbidity), and which communities are worst affected?

There is a growing body of evidence from at least two decades that demonstrates a clear link between increased temperatures and decreases in human health and wellbeing. WHO (2018) lists these as both direct and indirect effects as listed in the table below. Climate change has also aggravated 58% of infectious diseases (Mora et al, 2022). The IPCC Climate Change 2022 Impacts, Adaptation and Vulnerability report warns that rising global greenhouse gas emissions could soon outstrip the ability of many communities to adapt. Currently over half of the world’s population living in cities with that proportion expected to rise two-thirds by 2050 according to the World Bank indicators.

Some reports suggest possible mean summer temperatures in parts of southern England could increase by over 4oC by 2080 relative to the 30-year baseline starting in the 1960s (Arbuthnott and Hajat, 2017). There are also warnings of extreme heat events, especially in urban heat islands (UHIs) becoming more frequent. The health impacts resulting in early mortality include, but are not limited to, damage to cardiovascular and respiratory systems. In some cases this can be described as mortality displacement, meaning that deaths in the most at risk or vulnerable people have been accelerated by the environmental conditions. The greatest threat is during heat waves when average temperatures are higher than 5oC above the average maximum for that time of year. For example, in the August 2003 heat wave there was a 17% increase in deaths above the expected baseline (Johnson et al, 2005).

Risk factors include:

• Geographical location; London, Southeast England and East Anglia being most at risks regions the impact of UHIs is exacerbated in these regions
• Age; older people especially those over retirement age are most at risk as well as very young children who are less able to take action themselves to adjust their immediate conditions
• Gender; some epidemiological data indicates that women are more likely to be at risk than men
• Co-morbidities; underlying conditions such as certain psychological disorders, dementia, diabetes, kidney disease, alcohol dependency all show a various degrees of increased risk of mortality during periods of elevated temperature levels
• People who are working outdoors during heat waves (Lundgren, Kuklane and Holmer, 2013)
• Low socioeconomic status; has also been shown to increase negative health effects during periods of high temperatures possibly due lack of cooling technology such as fans or air conditioning and this can be further complicated by changes in air pollution associated with higher street level temperatures (Kovats and Hajat, 2008).

Cardiovascular strain is put on the heart when increased blood flow towards the skin reduces the flow to other (vital) organs, putting extra demand on the heart by reducing its atrial filling pressure, reducing the stroke volume and increasing heat rate. The fluid loss through excessive sweating can also lead to dehydration and heat related cell death (Ebi et al, 2021) Heat stroke occurs when the body’s thermoregulation system fails resulting in insufficient sweating and reduced cooling.

How can sustainable cooling solutions and adaptation strategies be implemented in such a way as to minimise overheating, reduce energy consumption and prevent overloading of the electricity grid during peak demand?

Nature-based Systems (NbS) have been proposed to help mitigate a number of climate related issues such as flood prevention or reduction (O’Donnell and Thorne, 2020), the improvement of urban air quality (Nemitz et al, 2020), reducing UHIs (Hobbie and Grimm, 2020), supporting carbon capture or sequestration (Bayulken, Huisingh and Fisher, 2020; Waller, 2023) and providing many ecosystem services generally (Castellar et al, 2021). Green infrastructure can help to limit urban warming by modifying air flows and heat exchange, and trees that provide both shading and cooling via evapotranspiration (Bowler et al, 2010). Green roof technology may employ soil that can act as an insulator and, depending on the type of structure, can lead to significant energy savings and cooler internal building temperatures (Jamei et al, 2023). Studies have shown that even simple hedges can cool urban environments by rates of over 1oC min-1 m2 (Zou, Yang and Qui, 2019). NbS require no input from the national grid and therefore they can help to prevent overloading of the national grid.

What actions can be taken to protect those most vulnerable to the impacts of extreme heat?

The strategy to reduce the health impacts of extreme heat must include:

Public education, awareness raising and information sharing:

Via schools, public broadcasts, NHS and other state and civil society bodies people should know that:

• maximum indoor temperatures should be 32oC in the day time and 24oC at night
• night air helps to cool properties by opening ventilation systems in the night and early morning
• closing south facing windows and curtains can help to insulate during the day time
• turning off non-essential electrical appliances will reduce the heat input
• using shades, wet towels, awnings and drapes can all help to cool properties
• air conditioning are most effective and efficient when windows and doors are kept shut
• fans help provide some relief but may not prevent heat related illnesses if it is above 35oC
• applying cool tap water intermittently to large areas of skin will reduce cardiovascular strain
• there are several benefits from using cool foot baths
• it is safer to stay in the shade
• it is recommended to only do strenuous activity such as sports and demanding manual tasks in the cooler evening or very early morning (and taking breaks to rest and rehydrate is important)
• animals and young children should not be left in parked vehicles
• many medicines should be kept below 25oC so it is recommended to store them in a fridge during heat waves
• it is advisable to keep the body hydrated through:
• taking cool baths or showers
• wearing light loose fitting clothes, wide-brimmed headwear and sunglasses
• drink plenty of water avoiding excessive alcohol or caffeine, which is a diuretic
• eat regular small meals avoiding high protein foods
• it is important to help others especially the very young and old to ensure they are taking the correct precautions, getting the correct fluid intake and not being left alone. (WHO, 2018)

National government should:

• ensure that the national grid electricity infrastructure has sufficient capacity to provide for more air-conditioning that will be likely to be installed and operated in the future. This is even more important when considering the anticipated massive increase in electricity demand with the plans for more electric vehicles
• continue to provide early warning systems and heat alerts
• promote and support research into sustainable cooling systems acknowledging that for many there are additional benefits such as economic advantages, reduced energy consumption, in addition to wellbeing and mental health benefits for people having access to green spaces
• do more to ensure the transition to electric vehicles since road traffic is currently predominately powered by internal combustion engines that generate large amounts of excess heat in urban centres. So, a workable strategy, with the accompanying infrastructure targets, is advisable
• legislate to ensure that all new buildings have renewable energy technology included in the planning and construction stages that will help to reduce carbon emissions and thermal costs.

Local authorities can help by:

• open air-conditioned cooling centres such as libraries, town halls and other public buildings
• subsidise access to swimming pools and increase to green space such as council owned gardens
• protecting urban forests, shaded parks, tree lined streets and other green spaces, all of which help to reduce UHI effects[1]
• provide an increased number of drinking fountains, shaded footpaths, and spray pads
• ensure that blue and green infrastructure is incorporated into all urban landscape design
• designing or remodeling school playgrounds with shaded canopies or sails
• ensuring care homes have adequate ventilation, air conditioning or fans and that staff are trained on low-energy intensive personal cooling techniques such as those listed above
• updating building regulations to ensure more green roofs and similar technologies are adopted
• provide information, grants and materials to promote tree planting and property insulation
• support the development of infrastructure at local levels to ensure the rapid transition to electric transport and legislate to limit the use of fossil powered vehicles in urban areas
• provide information and warnings on keeping cool especially at mass gatherings

What role might reversible heat pumps (which can act as both heating and cooling systems) and other emerging technological solutions, such as the development of smart materials, play in meeting future cooling demands?

Green infrastructural technologies include trees, roof coverage as well as vertical surfaces with potential for cooling effects (Koc, Osmond and Peters, 2018). Further environmental heat sinks for buildings, according to Kamal (2012) include:

• convection designs for air flow
• the use of water for evaporative cooling
• heat loss through longwave infra-red radiation to the night sky
• conduction of heat by transfer to the ground

At the most basic level it is vital to include shading in the design of new buildings, ensure maximum insulation is utilized and limit the amount of glass window coverage facing south and southwest. Heat pumps can also be used for cooling. Although air source heat pumps are about three times more efficient than fossil fuel boilers for heating, they do require electricity to run so may add to the overall grid demand. The government has a target of 600,000 heat pumps being installed every year within 5 years from now. Grants are being made available through the Boiler Upgrade Scheme. However, there are several barriers that are making people hesitant to adopt the conversion from gas boilers to heat pumps:

• the comparative cost
• the size of the technology
• the relatively lower level and rate of heat transfer
• the practicalities of installation including re-plumbing of pipework
• new improved technology is still being developed

For all of the above reasons many people are cautious and even skeptical about the promise of reversible heat pumps, and in some cases local planning regulations further complicate the process. In Hong Kong and Copenhagen, the use of huge seawater reservoirs has been proven to reduce energy costs of running community cooling systems. There could be scope for such systems in large coastal cities of the south of England such as London, Bristol, Brighton and Hove, Plymouth or Bournemouth and Poole. Less expensive and more universally available are solar reflective surfaces for buildings and pavements that have been tested and show promise in some cities (Gopalakrishnan et al, 2017; Middel et al, 2020; Manni and Nicolini, 2021). However, there are some drawbacks negative environmental effects on the acquisition, synthesis and processing of nanoparticle based materials, performance of retroreflective materials at low angles and the inclusion of toxic metals in phase change materials (Mourou et al, 2022).

Smart materials such as breathing skin, hydroceramics and hydromembranes can help to regulate internal humidity and cooling rates. Some smart systems can also help with automated shading and irrigation of green roof installations. Whether these innovations can deliver cost-benefits in the real world remains to be seen. Future possibilities include electrochromic materials that can change colour or opacity (Rao et al, 2021) and smart coatings such as those based on titanium oxide nanoparticles, along with fluorescent and glass microparticles (Xue, 2020). However, currently these are not quite at the commercialisation stage.

Summary recommendations

To protect the most vulnerable there must be clear and well broadcast information sharing campaigns and warnings, including some very basic advise as list above. The government must also work to coordinate work between departments to ensure that renewable energy strategies are aligned and ensure that health departments, energy, new building, construction and urban planning authorities all work towards the same goals of greening cities and ensuring a healthier and cleaner environment.

August 2023

References

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Bayulken, B., Huisingh, D. and Fisher, P.M.J. (2021) “How are nature based solutions helping in the greening of cities in the context of crises such as climate change and pandemics? A comprehensive review.” Journal of Cleaner Production 228:125569

Ebi, K.L. et al. (2021) “Hot weather and heat extremes: health risks.” Lancet 398: 698-708

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