With temperatures set to smash records and even reach 40 degrees Celsius, the government has declared England’s first national heatwave emergency.

On Sunday, Monday, and Tuesday, an Extreme Heat Warning is in effect for all of England and Wales, as well as parts of Scotland.

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During those hours, the temperature is expected to rival the hottest ever recorded – 38.7 degrees Celsius in Cambridge in 2019.

The COBRA committee of the government convened and resolved to raise the Heatwave Alert Level to 4, triggering a national emergency.

It refers to “illness and death occurring among the fit and healthy – and not just in high-risk groups.”

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When the UK sees three consecutive days of maximum daily temperatures exceeding a specific threshold, the Met Office declares a heatwave.

Thresholds vary by county, although the South and East of England have the highest levels.

What are the Heatwave Alert Levels?

Level 0

This basic notice urges authorities to have preparations in place all year to “reduce the impact of climate change and ensure maximum adaptation to reduce harm from heatwaves.”

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Level 1

Between the 1st and 15th of June each year, the Heatwave Alert Level remains at 1 in anticipation of the hotter summer weather.

This only serves as a reminder to social and healthcare agencies to be prepared.

Level 2

This is when the Met Office predicts that temperatures will be high enough on two consecutive days to have an impact on people’s health.

Level 2 is normally announced two or three days in advance since death rates climb as temperatures rise, and mitigation is critical.

Level 3

When the Met Office determines that threshold temperatures have been achieved in at least one region, this is declared.

To protect high-risk groups, quick action is required.

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Level 4

A Level 4 heatwave is classified as a “major incident” and a “national emergency.”

When “a heatwave is so severe and/or prolonged,” “illness and death may occur among the fit and healthy – and not just in high-risk groups.”

Power and water shortages are possible.

What may happen in the event of a national heatwave?

During a heatwave, the elderly, babies and young children, and those who are seriously physically or mentally ill are particularly at risk.

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Individuals living alone or in secluded places, in south-facing top-floor flats, those with drug and alcohol addictions, and the homeless are also at risk.

People outside of those groups, however, are at risk of becoming very ill or dying during a Level 4 emergency.

In terms of transportation, road surfaces are “susceptible to melting,” owing to direct sunshine.

Train tracks can also “warp or buckle under extreme prolonged temperatures,” requiring temporary speed limitations to prevent trains from derailing.

There are specific health hazards linked with the London Underground, where hot weather warnings and bottled water should be provided, as well as precautions needed to prevent the tracks from buckling.

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High temperatures reduce power plant efficiency, with nuclear reactors at risk of tripping at 40 degrees Celsius.

Water quality could be harmed, resulting in toxic algal blooms that destroy fish and other aquatic life.

Wildfires can be sparked by drier-than-usual grass and vegetation.

Officials also warn of the “potential for an increase in the number of pet fatalities due to irresponsible owners leaving them in restricted enclosures with poor ventilation.”

Increased demand for water resources, particularly in the south, might lead to local hosepipe restrictions.

If classrooms grow excessively hot, they may have to be closed and students sent home.

Extreme heat can also result in crop damage, spoilt produce due to overheated storage conditions, and lower-than-normal yields of fruits, vegetables, and grains.

On July 25, 2019, the hottest temperature ever recorded in England was 38.7 degrees Celsius at Cambridge Botanic Garden.