Responses to extreme heat in the UK should consider implications for reducing emissions

Candice Howarth details some of the complexities involved in increasing the country’s preparation and resilience to the growing threat of heatwaves, including the need to ensure that solutions do not contribute additional greenhouse gas emissions.

The Grantham Research Institute continues to lead work on the UK’s response and strategies to enhance the country’s resilience to extreme heat. Often, this is considered a seasonal issue, only relevant to the summer months, but the picture is more complicated than that, with even milder temperatures being able to severely affect certain people. Adding to this complexity is the need to ensure that responses to extreme heat do not lead to unintended consequences or ‘maladaptation’.

The need for a greater and more strategic response

The year 2024 was the warmest year on record, with average temperatures close to 1.55°C above pre-industrial levels. Global greenhouse gas emissions continue to rise, meaning the impacts of climate change will continue to deepen. Higher temperature and the projected increase in frequency, magnitude and duration of heatwaves pose significant challenges. In the UK alone, extreme heat is expected to directly impact people’s health as well as the energy and transport sectors, our buildings and infrastructure, health and care services, crop production and air quality, as highlighted in our report published in 2024.

The heatwave periods experienced in the UK during the summer of 2022, when temperatures reached over 40°C and the Government declared a national emergency following the Met Office’s first ever red ‘extreme heat’ warning, were associated with 2,985 excess deaths. The UK is still not prepared for extreme heat, with its extreme heat response being piecemeal, lacking a multi-sectoral approach, and not sufficiently incorporating solutions that reflect local opportunities or challenges. A way forward could be the establishment of a National Heat Risk Commission, as discussed in our inaugural Adeline Talks series roundtable in February 2025.

Measures such as the Heat Health Alert system play an important role in ensuring the nation is on alert and resources are deployed appropriately during the summer. But this is faced with behavioural and cultural barriers and will only be effective if it is part of a wider strategic focus that seeks to enhance our preparedness to overheating in the long term and not just confined to summer months. Such a strategic focus should consider, among other factors, that heat does not affect people equally, either in terms of direct impacts (and how circumstances and surrounding environment influence these) or in terms of people’s means to prepare, adapt and respond to heat events. For instance, evidence shows that certain neighbourhoods and building typologies can be more impacted by overheating than others.

A workshop we held in October 2024 explored how preparations for extreme heat in London underscore the importance of coordinated strategies to tackle the rising risk of heatwaves in the context of multiple or concurrent risks (e.g. power outages or wildfires). Participants from first responder organisations, charities, local authorities and government organisations highlighted the need to develop both short- and long-term cooling solutions that would not increase greenhouse gas emissions. Short-term strategies include enhancing access to air conditioning and implementing mobile cooling solutions such as electric vehicle-based cooling systems. Long-term approaches focus on reducing greenhouse gas emissions by exploring sustainable alternatives such as green infrastructure (e.g. planting trees for shade) and heat-resilient urban planning. Addressing the combined risks of heatwaves, wildfires and potential power outages emerged as a critical area for further attention, with stakeholders stressing the need for targeted contingency plans.

Additionally, the research findings point to the need for robust training for frontline workers and public officials to respond effectively to extreme heat events. Public awareness campaigns are deemed vital to inform residents about heat risk and protective measures, especially for vulnerable people such as the elderly and those with pre-existing health conditions. We have also found that cultural barriers and lack of awareness can significantly hinder the uptake of measures to mitigate the impacts of heat. This is further compounded by insufficient consideration for how to do this in a way that is low in emissions.

Building a low-emissions response to heat

The Met Office’s three-month outlook published on 1 April 2025 indicates that the period April to June 2025 is likely to be warmer than average. We know that we do not need to reach the record-breaking temperatures experienced in 2022 for the health impacts of heat to be felt, so the country needs to be prepared. We must continue to put measures in place to adapt and respond to the impacts of heat while minimising avoidable increases in emissions.

Our research is ongoing but below we outline a series of recommendations principally for the UK but that are applicable more widely.

1. Give higher prominence to low greenhouse gas emission approaches to enhance heat risk preparedness. Siloed approaches to heat risk preparedness, prevention and protection fail to provide a full picture of the complexity of the issue. Low-emission responses are needed to ensure effective responses do not make the underlying issue worse, and that unintended consequences and complexities are fully considered.
2. Implement fully-funded, year-round, complementary low-emission preparedness and responses to heat risk. Efforts to tackle the impacts of extreme heat and better prepare the UK for these impacts without increasing emissions must be appropriately funded and bring together passive and active measures that are behavioural and/or cultural, institutional, infrastructural and/or technological, and ecosystem- or nature-based. These responses and general preparedness to heat need to be considered as a year-round issue, not just limited to summer periods.
3. Reduce over-reliance on responsive measures. Proactive responses to heat risk are needed to enhance low-emission approaches to improve heat risk preparedness and resilience. Behavioural and cultural measures must be rebalanced to enable more room for preparatory and preventative approaches that would reduce an over-reliance on reactive and protective responses.
4. Identify and integrate ‘non-negotiable’ elements into measures. Essential, ‘non-negotiable’ elements must be identified and carefully integrated into heat preparedness and responses to ensure the use of active responses (such as energy-intensive air conditioning systems) that may result in emissions are part of a broader solution for heat risk preparedness in which those most affected and vulnerable to heat are not put further at risk (e.g. in hospitals, prisons and those in domiciliary care, school and care settings).
5. Learn from others. Institutional approaches to low-emission heat preparedness and prevention in the UK must learn from international experience and carefully consider establishing appropriate mechanisms such as Heat Officers and localised Heat Health Action Plans to pre-empt the severity and urgency of heat risk the nation will face during and outside heatwave periods.
6. Address heat inequalities and unintended consequences. While effective low-emission cooling measures can be implemented, such as green spaces or urban water parks, if access to these facilities is not equal or fair, or unintended consequences are not properly considered, this can further enhance disparities between vulnerable groups.
7. Approach heat vulnerability as a dynamic phenomenon. The way in which vulnerability to heat is determined needs to be reviewed to better prioritise low-emission approaches. Those who are not considered vulnerable to heat could become vulnerable particularly during Level 4 Heat Health Alerts. Although groups most vulnerable to heat are known (and include children under the age of 5, adults over 65, those with underlying health conditions, pregnant women and outdoor workers), research suggests some of these groups (e.g. those over the age of 65) do not tend to identify as vulnerable, which may limit their awareness, knowledge and take-up of behavioural protective measures that can minimise their exposure to heat.
8. Develop and implement Monitoring, Evaluation, Accountability and Learning (MEAL) standards and practices. The implementation of heat adaptation and mitigation measures (e.g. behavioural and/or cultural, institutional, infrastructural and/or technological, and ecosystem- or nature-based) need to incorporate monitoring and reporting systems that provide reliable success measures and incorporate information related to emissions and emissions-saving alternatives.

We will continue to explore practical ways to inform ongoing processes that can enhance preparedness to extreme heat, mitigate its impacts and do so in a way that minimises emissions.

Read our detailed findings in a newly published report, ‘Resilient net zero: exploring low-emission cooling solutions to extreme heat’, made possible by a Fellowship funded by the British Academy and led by Dr Candice Howarth.