What is the EU Taxonomy?
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Discover the EU Taxonomy: what it is, how it defines sustainable activities, and its impact on businesses and financial markets.
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Surviving a UK Heatwave: Tips for People and Companies
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The UK used to be known for its mild, damp summers – more drizzle than danger. But that reputation no longer holds. In just the past three years, the country has experienced its hottest years on record, relentless heatwaves, and record-breaking rainfall. This summer alone, much of the UK has already endured three separate heatwaves, with scorching temperatures stretching from the southeast to Scotland and Northern Ireland.
“According to the Met Office’s latest report, this isn’t a one-off – extreme weather is now the new normal. Heatwaves are more frequent, last longer, and affect more people. And while we’re getting hotter, we’re also getting wetter, with winter rainfall up 16% compared to historical averages. For individuals and companies alike, the UK’s changing climate brings growing risks to health, infrastructure, and daily life.”
So how can we adapt?
In this article, we’ll explore:
- What causes heatwaves – and why they’re getting worse
- What the latest 2025 data tells us about the UK’s changing climate
- How extreme heat impacts our health, cities, and nature
- What companies can do to protect employees and operations
- Practical tips to stay safe and resilient during future heatwaves
What is a heatwave? A quick overview
“A heatwave is an extended period of abnormally hot weather, typically lasting several days or more. It occurs when temperatures remain well above the seasonal average, often accompanied by high humidity, which can make the heat feel even more intense.”
Heatwaves usually form when a high-pressure system becomes stationary over a region. This system traps warm air near the surface and suppresses cloud formation, leading to dry weather and allowing uninterrupted sunshine to heat the ground and the air above it. Without cooler air moving in, temperatures continue to build over time.
These events are more than just uncomfortable, they can have serious consequences. From increased risks of heat-related illness to pressure on infrastructure, agriculture, and energy supply, heatwaves are among the most disruptive and dangerous types of extreme weather, especially in regions not used to prolonged high temperatures.
What causes a heatwave?
Heatwaves might feel simple, but the conditions that create them are anything but. These events are driven by a combination of atmospheric patterns, ground-level conditions, and climate-related feedback loops. Understanding what causes a heatwave helps explain why they’ve become more frequent, more intense, and harder to predict.
| Cause | What it is | How it contributes to a heatwave |
|---|---|---|
|
Persistent high-pressure systems
|
Large-scale zones of sinking air in the atmosphere | These systems suppress cloud formation and block cooler air from entering. The descending air compresses and warms, leading to prolonged periods of heat and minimal cloud cover. |
|
Jet stream disruption
|
A high-altitude ribbon of fast-moving air that guides weather systems | When the jet stream becomes wavy or weak, it can trap high-pressure systems over one region — preventing cooler systems from moving in and allowing heat to build. |
|
Clear skies and solar radiation
|
A result of high-pressure systems inhibiting cloud formation | Without cloud cover, more solar energy reaches the ground, rapidly heating the surface and the air above it. Nights remain warm too, as less heat escapes. |
|
Urban heat island effect
|
The tendency for urban areas to retain more heat than rural surroundings | Dense surfaces like concrete and asphalt absorb heat during the day and release it slowly at night, making cities hotter — especially during heatwaves. |
|
Dry soil and land-surface feedback
|
Lack of soil moisture, often due to prior drought or low rainfall | With less moisture to evaporate, more solar energy goes into heating the surface, intensifying and prolonging heatwaves. This is a positive feedback loop. |
|
Climate change
|
Long-term increase in global surface temperatures due to greenhouse gas emissions | A warmer climate raises the baseline for all weather, making heatwaves more frequent, more intense, and more likely to exceed historical extremes. |
Why does this matter?
Heatwaves are no longer rare or isolated events. Studies show that in the UK, extreme temperatures above 30°C are now significantly more likely than they were before industrialisation - around 10 times more likely for multi-day heatwaves, and up to 100 times more likely for single-day temperature spikes above 32°C in parts of southern England.
This sharp rise is largely due to human-induced warming. And it’s not just about temperature extremes: these conditions trigger a cascade of impacts, from droughts and crop failures to health emergencies.
By understanding the science behind heatwaves, we can better predict, prepare for, and mitigate their growing impact.
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Why is climate change making heatwaves worse?
Human influence is intensifying heatwaves by altering the very systems that regulate our planet’s temperature. The key factor is the rising concentration of greenhouse gases, like carbon dioxide and methane, in the atmosphere. These gases trap more of the sun’s heat – a process known as the enhanced greenhouse effect – which raises global surface temperatures over time.
As the Earth warms, this has several knock-on effects that make heatwaves more likely and more severe:
Higher baseline temperatures
Mean that when a heatwave does occur, it starts from an already elevated level, so peaks are hotter, and extremes are easier to reach.
Faster soil drying
Soil dries out more quickly in warmer conditions, reducing evaporative cooling. This allows surface temperatures to rise even faster during hot spells.
Jet stream disruption
Warmer oceans and land surfaces feed back into the atmosphere, altering jet stream patterns and increasing the likelihood of “blocking highs” (the stalled high-pressure systems that cause prolonged heat).
Hotter nights
Nighttime temperatures also rise, giving less relief during heatwaves and amplifying health risks.
In short, climate change shifts the odds. Events that might have happened once a century are now happening far more often and with more dangerous consequences.
“2024 was the hottest year on record, with temperatures approaching the critical 1.5°C threshold. As emissions continue, the risk of extreme heat will only grow.”
UK heatwaves: What's happening?
“The UK has always been known for unpredictable weather, but in recent years, the unpredictability has taken on a new dimension. Heatwaves are no longer rare or regional. They’re now recurring, widespread, and increasingly disruptive.”
In the summer of 2025, the UK has already experienced three separate heatwaves, starting as early as mid-June, with temperatures climbing to 33–34 °C across much of England, Wales, Northern Ireland, and even parts of Scotland - levels more commonly seen in western and southern Europe. June 2025 was confirmed as the hottest June on record for England, and the second hottest for the UK as a whole since records began in 1884.
The Met Office has also warned of more frequent “tropical nights” - where the overnight minimum temperature doesn't drop below 20 °C - making it harder for people to recover between hot days. Meanwhile, multiple English regions, including Yorkshire and the North West, have been moved into formal drought status, with hosepipe bans already in place.
These events are not one-offs. Data from hundreds of UK weather stations show that:
The number of days with temperatures 5°C above the 1961–1990 average temperatures has doubled in the past decade.
Days exceeding 8°C above average have trebled, and 10°C exceedances have quadrupled.
The past three years – 2023, 2024, and 2025 – are now among the hottest on record for the UK.
“As the UK warms, what once felt like a rare anomaly is now becoming a pattern, raising serious concerns for public health, infrastructure, and water security.”
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What counts as a heatwave in the UK?
“In the UK, a heatwave is officially declared by the Met Office when a location records temperatures at or above a specific threshold for three consecutive days. These daily maximum temperature thresholds vary across the country to reflect local climate norms - what's extreme in Scotland may be typical for parts of southern England.”
| UK Region | Heatwave Temperature Threshold (°C) |
|---|---|
|
Scotland, Northern Ireland
|
25 °C |
|
Northern England, Wales, South West England
|
25 °C |
|
Central and South East England
|
26 °C to 28 °C |
Note: These thresholds are reviewed regularly and may be adjusted over time as UK temperatures continue to rise.
How does this compare globally?
What’s considered a heatwave also varies by country, both in terms of temperature and definition. Here's how the UK stacks up:
| Country | Typical Heatwave Threshold | Definition |
|---|---|---|
🇬🇧 United Kingdom |
25–28 °C (region-specific) | 3+ consecutive days at or above threshold |
🇺🇸 United States |
32 °C+ (90 °F) | Often defined by local norms + heat index |
🇮🇳 India |
40 °C (plains), 30–37 °C (hills) | Must persist for 2+ days; 45 °C = severe |
🇫🇷 France |
Varies by département, generally 30–35 °C | Declared alongside health alerts (Plan Canicule) |
🇦🇺 Australia |
Varies by region; often 35 °C+ | Also includes overnight minimums |
“While UK thresholds may seem modest compared to other countries, it's important to remember that infrastructure, housing, and public health systems here are not designed for prolonged heat, making these temperatures disproportionately disruptive.”
Is climate change making heatwaves worse in the UK?
“Yes - and the evidence is clear. The UK is now seeing the clear and growing impacts of climate change. Extreme heat, heavy rainfall, and sudden weather swings are becoming increasingly common, forcing policymakers, scientists, and the public to rethink how we prepare for and respond to these events.”
As global temperatures rise, so too does the frequency and severity of heatwaves, and the UK is not immune. What were once rare spikes in summer heat are now becoming regular, prolonged episodes. These changes pose risks not only to public health and infrastructure, but also to the UK’s natural landscapes and cultural heritage. During the 2022 heatwave, for example, a fire near Stonehenge came dangerously close to one of the country’s most iconic sites.
At the same time, the climate is becoming more unpredictable. The summer of 2024 was a case in point, marked by a bizarre mix of cool spells, heavy downpours, and record-breaking heat, sometimes within the same month. Events like Wimbledon, Glastonbury, and school term endings were all disrupted by weather extremes, revealing just how quickly our traditional seasons are becoming blurred.
“This volatility underscores a key point: climate change isn’t just making the UK hotter, it’s making the weather more unstable. And in a country where infrastructure was built for temperate conditions, that shift carries serious consequences.”
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How do heatwaves impact the UK?
Heatwaves are not just uncomfortable, they have far-reaching effects on people, nature, infrastructure, and the economy. And in a country like the UK, where buildings and systems were designed for milder conditions, the risks are especially acute.
Impact on people and public health
The health effects of heatwaves are often underestimated. But as temperatures climb, so does the risk to human life:
🧓👶 Vulnerable groups
Older adults, babies, pregnant women, people with chronic conditions, and those without access to cooling (like the homeless or people in poorly ventilated housing) are especially at risk.
🌆 Urban heat islands
Cities like London trap more heat due to dense buildings, tarmac, air pollution, and limited green space - raising temperatures even further for residents.
💔 Health impacts
- Heat exhaustion, stroke, cramps – with symptoms like muscle pain, dizziness, nausea
- Increased risk of heart attacks and strokes
- Respiratory issues, especially for people with asthma
📈 Rising fatalities
In 2023, the UK saw an estimated 2,295 heat-related deaths, according to the UK Health Security Agency.
“During the July 2022 heatwave, record-breaking temperatures meant that the UK had to issue its first-ever national heat emergency with a Level 4 alert, highlighting just how dangerous prolonged heat has become, even in temperate climates.”
Impact on nature and wildlife
The UK’s ecosystems are also feeling the pressure of hotter, drier summers:
Drought conditions
Prolonged heat reduces water levels in rivers and reservoirs.
Increases the risk of hosepipe bans and agricultural water stress.
Wildfires
Heatwaves dry out grasslands and moorlands, raising the risk of fires.
Includes threats near protected sites like Stonehenge (2022).
Biodiversity disruption
Shifts in seasonal timing signal ecological imbalance.
Earlier nesting, frogspawn, or hazel flowering are signs of disruption.
Heat stress on animals
Wildlife and livestock suffer in high temperatures.
Especially when water and shelter are scarce.
Impact on infrastructure
The UK’s infrastructure wasn’t built with extreme heat in mind, and the cracks are starting to show:
Transport disruptions
Railways buckle, roads melt, and flights get grounded.
High temperatures deform infrastructure, halting movement.
Building design
Many homes and public buildings trap heat in summer.
Poor ventilation can make schools and hospitals dangerously hot.
Power and water strain
Cooling and water demand surges during heatwaves.
Can lead to outages and overwhelmed systems.
In many UK homes and public buildings, air conditioning is still rare, meaning there’s often no way to escape the heat indoors.
Impact on businesses and the economy
From farms to offices, heatwaves disrupt operations and hit productivity:
🌾 Agriculture
- Heat and drought reduce crop yields
- Livestock face heat stress and reduced grazing capacity
👷 Workforce productivity
- Outdoor workers (e.g. farmers, builders) are vulnerable to heat exhaustion
- Indoor workers in poorly ventilated offices and schools struggle to focus and perform
🚚 Supply chain issues
- Delays caused by transport disruptions
- Spoilage of perishable goods in transit
💡 Energy costs
- Surge in air conditioning use leads to higher energy bills and grid strain
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How can companies protect their employees during a heatwave?
Employers can’t control the weather, but they can take meaningful steps to safeguard staff health and maintain productivity when temperatures rise.
🩺 Health & Well-being
- Monitor indoor temperatures regularly
- Identify vulnerable employees (eg. pregnant, health conditions, medication-sensitive)
🏢 Work Environment
- Provide cold drinking water
- Improve ventilation or install portable AC units
- Relax dress codes for breathable clothing
🕓 Flexible Working
- Allow remote work where possible
- Shift working hours to cooler times of day
☀️ Heat Safety Protocols
- Train staff to recognise heat stress symptoms
- Schedule frequent breaks in shaded or cooled spaces
- Prioritise rest for outdoor workers
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How to stay safe during a heatwave
While businesses play a role in protecting workers, it’s also important that individuals take steps to look after themselves and others when extreme heat hits. Small changes can make a big difference to your comfort, health, and resilience.
Here are some simple but effective actions you can take:
🤝
Stay connected and check on others
- Look out for vulnerable people – especially older people, friends, and relatives with medical conditions.
- Stay in touch during heatwaves – even a quick call or text helps.
🪟
Keep your home cool
- Close blinds or curtains during the day to block sunlight.
- Open windows at night to let cooler air in.
- Avoid using ovens or stovetops during the day.
🏃♀️
Avoid exertion
- Avoid intense physical activity during the hottest part of the day.
- If needed, exercise early in the morning or later in the evening.
🌞
Limit sun exposure
- Stay indoors from 11 am to 3 pm if possible.
- If going out, wear sunscreen, sunglasses, and a wide-brimmed hat.
❄️
Use fans or AC wisely
- Use electric fans or air conditioning to cool your space.
- Avoid fans if indoor temps are above 35°C – they may make it worse.
💧
Stay hydrated
- Drink water regularly – don’t wait to feel thirsty.
- Avoid alcohol, sugary drinks, and too much caffeine.
🧊
Prepare in advance
- Check the forecast and sign up for heat health alerts.
- Ensure cooling devices are working properly.
- Stock up on water, food, and essential medications.
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How can we reduce the risk of future heatwaves?
While personal actions can help us cope with extreme heat, long-term solutions require systemic change. To reduce the frequency and intensity of heatwaves, we need to tackle the root cause: climate change.
As the planet warms, these extreme events are becoming more common, and without decisive action, the risks to our health, economy, and environment will continue to rise.
What needs to happen?
🌍
Prevent further global warming
The most effective way to limit future heatwaves is by reducing global emissions. This means shifting away from fossil fuels and investing in renewable energy sources like wind and solar.
🏙️
Support sustainable infrastructure and transport
Improving building insulation, reducing car dependency, and expanding public transport options can help lower emissions and improve our heat resilience.
🌱
Adopt more sustainable lifestyles
From cutting down on meat and waste to saving energy and water, individual choices matter, especially when amplified at scale.
📢
Back bold climate policies
Governments must be held accountable for delivering on climate targets. Support for net-zero strategies, nature restoration, and climate adaptation plans is essential.
“If we act now, we can limit warming and reduce the risk of extreme heat becoming the new norm.”
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How can Greenly help?
To effectively combat climate change and its impacts, companies need to take proactive steps in reducing their carbon footprint. Greenly offers a suite of sustainability services designed to help businesses achieve this goal.
| Service Area | What It Includes |
|---|---|
|
Carbon management
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Decarbonising your supply chain
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Intuitive and seamless platform
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Greenly offers comprehensive support for your sustainability journey, from carbon measurement and custom action plans to supply chain decarbonisation and platform integration. With our help, your business can significantly reduce its environmental impact and achieve lasting sustainability.
Contact Greenly today to start leading the way in sustainability and build a greener future for your company.
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