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expert reaction to hot weather and climate change

A heat-health alert has been issued for parts of the UK this week as the Met Office forecasts high temperatures.


Dr Mark McCarthy, head of the Met Office National Climate Information Centre, said:

“The highest temperatures experienced in the UK tend to occur when our weather is influenced by air masses from continental Europe or North Africa, as it will be at the weekend.  There is already a strongly-embedded warming due to climate change across the continent that is increasing the likelihood of challenging the existing UK temperature record.”


Dr Melissa Lazenby, Lecturer in Climate Change at the University of Sussex, said:

“Heatwaves have increased in intensity, frequency and duration in observations and are predicted to continue on this upward trend in future. This is a result of human induced climate change and the evidence is clear, as we are currently experiencing a heatwave in the UK which has the potential to break the current maximum temperature record later this week. Heatwaves and their associated impacts are going to be something that we need to get used to and make sure we can adapt to now and in the future.”


Dr Radhika Khosla, Associate Professor at the Smith School of Enterprise and Environment, University of Oxford.

“The heat we are seeing this week is quickly becoming the ‘new normal’ for the UK. Responding to rising temperatures, just a few months ago the Met Office even raised the threshold of what counts as a heatwave in some parts of the UK.

“But we must be careful not to downplay the risks of heatwaves, which can be deadly for the vulnerable, elderly and very young, and hamper food supply and human productivity.

“As overall temperatures rise in the UK due to climate change it’s important to adapt to extreme heat with sustainable cooling options that don’t contribute to making the problem worse.”


Dr Laurence Wainwright, Departmental Lecturer at the Smith School of Enterprise and the Environment, University of Oxford, said:

“Heatwave events can have a significant impact on both physical and mental health. Key areas of the brain – especially those responsible for solving complex cognitive tasks – are impaired by heat stress.

“There are significant and positive associations between daily high temperatures and suicide. Roughly speaking, for every 1℃ increase in monthly average temperature, suicide rates increase by 1-2%.

“There is strong evidence that heatwaves exacerbate symptoms in those with underlying mental health conditions. Acute and sub-acute weather events – including heatwaves – have been linked to a rise in the manifestation of depressive symptoms in those with an underlying diagnosis of Major Depressive Disorder. The same is true of anxiety symptoms in those with Generalized Anxiety Disorder. 

“There is strong evidence linking extreme heat with aggression, and subsequent rates of violent assault. Various studies have shown a moderate rise in violent assault on hot days. Even just a one or two degree Celsius increase in average monthly temperatures can lead to a 5-10% spike in assaults. 

“Further problems are posed by the fact that the effectiveness of key medications used to treat psychiatric illnesses can be reduced by the effects of heat. Some of these drugs increase the risk for heat related mortality, for example antipsychotics, which can suppress thirst.

“But there is reason for hope. Heatwaves, as disruptive as they can be, give us a unique opportunity to study mental health conditions in a novel manner – and in doing so provide a window of opportunity for identifying new methods of treatment and management and better understanding how medications work. They also provide us with a very tangible reminder that the best thing we can do to do help ourselves, and future generations, manage the health impacts of heatwaves, is to act on climate change.”


Dr Vikki Thompson, Climate Scientist at the University of Bristol Cabot Institute for the Environment, said:

“Climate change is making heatwaves hotter and last longer around the world. Scientists have shown that many specific heatwaves are more intense because of human-caused climate change. The climate change signal is even detectable in the number of deaths linked to heatwaves. Here in the UK the hottest day of the year is, on average, nearly 1°C warmer than in the 1970s. Across Britain extended periods of hot weather have doubled in length since the period 1961-1990. Southeast England has seen the greatest changes – with a tripling of warm spells. 

“The UK record temperature is 38.7 °C from Cambridge in 2019. Forecasts are suggesting this could be broken in the coming weeks, with record smashing temperatures over 40°C possible, according to some models, but not likely.

“Heatwaves are one of the most deadly natural hazards, in the UK ~3000 deaths were linked to heatwaves in 2021. The health issues related to heat include direct effects, such as heat stroke and cardiovascular failure, and indirect effects including poorer mental health and an increase in accidents such as car crashes and drownings. To keep safe make sure you stay cool, drink plenty of water, and wear suncream. Look out for the more vulnerable such as young children and older people.”


Dr Eunice Lo, a climate scientist at the University of Bristol Cabot Institute for the Environment, said:

“The current hottest UK temperature is 38.7C, recorded at Cambridge Botanic Garden in July 2019. Scientists expect this record to be broken in the future because of climate change, and temperatures this weekend are forecast to come close to this.”

“Heatwaves are becoming more frequent and intense as the globe warms up, so we can expect more and hotter heatwaves in future. Scientists have linked past heatwaves to human-induced emissions of greenhouse gases, which have contributed to climate change. The more greenhouse gases we put into the atmosphere, the more likely it is to have record-breaking temperatures.

“Extreme heat can be dangerous to human health. The UK Health Security Agency estimated that more than 2,000 extra deaths were related to heatwaves in 2020. It is important to stay hydrated, stay indoors or under shade, and check on friends and family during a heatwave, especially children, older people and those who have underlying health conditions. While sunny weather is often much-welcomed, it’s important not to underestimate the health impacts of heat and to take appropriate precautions.”


Prof Hannah Cloke, a natural hazards researcher at the University of Reading, said:

“This current hot spell in the UK is forecast to intensify over the coming days. While there is still some uncertainty in the forecasts for a week from now, the indications are that there is a small chance that we will hit record maximum temperatures in the UK, with highs close to 40 degrees Celsius.

“This is a dangerous level of heat on its own. We should remember that heat is most dangerous when it is persistent over several days, especially for those who cannot escape it or gain respite at night time.

“Extreme cold is currently still the biggest weather killer of people in the UK, but studies have shown that heatwaves will begin to take over as the most dangerous natural hazard in years to come, if climate change continues without radical cuts to greenhouse gases.

“Whatever our future holds, that people are dying of heat or cold in Britain in 2022 is frankly a national disgrace. There is clearly a short-term link with the rising costs of heating or cooling our homes. But there is a much more significant long-term link with poorly designed buildings and infrastructure, that only carefully co-ordinated, far-sighted planning can overcome.

“We have made great strides in forecasting extreme weather and climate conditions in recent years. Now we need the systems in place so that people and governments act on the warnings we can provide, whether three hours, three days, or three decades in advance.”


Prof Richard Allan, Professor of Climate Science, University of Reading, said:

“Heatwaves are caused by weather patterns that produce persistent high pressure, cloud-free conditions and dry continental winds during summer. Climate change is intensifying these heatwaves as greenhouse gas increases raise temperatures and a warmer, more thirsty atmosphere dries out the soil so that more of the sun’s energy is available to heat the ground rather than evaporating water.

“Extreme heat and drought is already affecting western and southern Europe and so when pulses of this hot, arid continental air blow from the south the heat rapidly builds across southern Britain and moves north.”


Prof Nigel Arnell, Department of Meteorology, University of Reading, said:

“The current heatwave has certainly made the headlines. It’s not the first this year, and probably won’t be the last. And we’ll get more next year, and the year after, and so on. Our analysis1 shows that we are highly likely to get more and longer heatwaves in the future due to climate change, for the numbers of heat-health alerts, heat-stress days – days when it is too hot to work – and damaging heat extremes to increase.  Work by colleagues in the Department of Meteorology2 shows that heat-related mortality will increase. Not only does this affect individuals, families and communities, it all puts pressure on our health services and economy.

“We’re not really geared up to deal with more frequent heatwaves, other than through enacting emergency plans, and we can’t really run in crisis mode each and every summer. New building regulations have just come into force to reduce overheating risks in homes, but that will take years to have an impact. We urgently need to improve our existing housing stock to better insulate against both hot and cold weather – and that will help reduce our exposure to rising energy bills too. It’s a win-win, but it’s complicated because lots of different departments, organisations and householders need to be involved: it needs to be given a much higher priority by government than it has now.”

1Arnell, N.W. & Freeman, A. (2021) The impact of climate change on policy-relevant indicators of temperature extremes in the United Kingdom. Climate Resilience and Sustainability doi. 10.1002/cli2.12

2Huang, W.T.K., Braithwaite, I., Charlton-Perez, A., Sarran, C. and Sun, T. (2022) Non-Linear Response to Global Climate Change of Temperature-Related Mortality Risk in England and Wales. Environmental Research Letters 17, 034017


Dr Michael Byrne, Reader in Earth & Environmental Sciences at the University of St Andrews, said:

“The current heatwave is a dangerous reminder of the accelerating impacts of global warming. With London expected to feel like Barcelona by 2050, the UK is braced for more frequent and severe heatwaves over coming years.

“Extreme heat is a severe threat to public health that – as pointed out by the UK Climate Change Committee only last year – the UK is woefully under-prepared to deal with. We urgently need to overhaul UK infrastructure to keep us cool & healthy in a rapidly warming world.” 


Dr Friederike Otto, Senior Lecturer in Climate Science, The Grantham Institute for Climate Change, Imperial College London, said:

“When it comes to summer heat, climate change is a complete game changer and has already turned what would once have called exceptional heat into very frequent summer conditions. Every heatwave we experience today has been made hotter because of the fossil fuels we have burned over the last decades in particular.

“This is no reason to cheer, heatwaves are by far the deadliest extremes in Europe. In 2020, in the UK alone more than 2500 people died because of hot days – and those were less hot and less frequent than what we are already seeing this year.”



Declared interests

Prof Nigel Arnell: “no conflicts of interest.”

Prof Hannah Cloke is a natural hazards researcher & climate expert. Her research is funded by UKRI NERC, UKRI EPSRC, FCDO & the European Commission. She is a member of UKRI NERC council and a fellow of ECMWF. She advises the Environment Agency and DEFRA on environmental hazards.

For all other experts, no reply to our request for DOIs was received.

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