Four ways winter heatwaves affect humans and nature

Temperature anomaly in Europe, Jan 1. Much of the continent was 10°C or more (dark red and grey) above the long-term average.
WX Charts, CC BY-NC

An extreme winter heatwave meant countries across Europe experienced a record-breaking New Year’s Day. New daily temperature records for the month of January were set in at least eight countries: Belarus, Czechia, Denmark, Latvia, Liechtenstein, Lithuania, Netherlands and Poland.

In many cases the temperatures were not just breaking the old highs, but smashing them by massive margins. On a typical January day in Warsaw, Poland, temperatures would barely go above freezing, yet the city recently experienced 19℃, breaking the previous January high by 5.1℃.

New January records were set at thousands of individual stations in many other countries such as 25.1℃ at Bilbao airport in Spain, 0.7℃ hotter than the previous record set only last year. Large areas of central and Eastern Europe experienced temperatures 10℃ to 15℃ warmer than average for this time of year – and that has persisted through the week.

When Europe experienced extreme heat in July of last year, more than 20,000 died. Fortunately winter heatwaves are much less deadly, but they can still affect both human society and natural ecosystems in many ways.

1. Less energy is needed

In Europe deaths due to cold weather vastly outweigh those caused by extreme high temperatures – in the UK there are ten times more. Warmer winters will reduce this excess mortality and, with the current cost-of-living crisis, many will have been relieved that a heatwave meant less energy was needed to heat their homes.

Electricity demand is influenced by things like the time of day, the day of the week and socio-economic factors like the COVID pandemic or the war in Ukraine. The weather also makes a difference. For example, in Poland and the Netherlands demand was noticeably lower than average, especially since January 1 was a Sunday. The extent of the heatwave also meant countries could refill some of their winter gas reserves, or large batteries.

Energy consumption in Poland December 28 to January 5. The red line shows the 2022-2023 heatwave period, and the grey lines show available data from 2015-2022.
Hannah Bloomfield / data: transparency.entsoe.eu, Author provided

2. Reduced yields for some crops

Winter warm spells don’t always have such a positive impact though. For instance a lack of snow in the mountains affects agriculture and can reduce crop yield, since snow creates an insulating blanket that prevents frost from penetrating into the soil. This means snow can actually increase soil moisture more than rainfall, thus improving growing conditions later in the season.

The big snow melt in spring time replenishes reservoirs and allows hydroelectricity generation, but unexpected snow melt can lead to flooding. Changes to the timings of these events will require preparation and adaptation to enable a steady supply of water to where we need it.

Warmer temperatures will create longer growing seasons in many regions. This is not always the case though. A recent study showed that for alpine grasslands an earlier growing season (the point when snow has melted entirely) leads to ageing and browning of the grasses in the later part of the summer.

3. The snow economy is in trouble

The heatwave caused ski resorts across the Alps to close in what should be their busiest time of year. In January the slopes would be expected to have a good covering of snow – but instead we saw green grassy fields.

This hits the local economy where many people rely on winter sports tourism. Events such as the Adelboden alpine ski World Cup are relying on artificial snow, which comes with a further environmental cost increasing the carbon footprint of ski resorts and requiring a large water supply. Indeed, the Beijing winter Olympics used the equivalent of daily drinking water for 900 million people to generate the artificial snow it required.

4. Animals out of sync with the climate

We humans are perhaps fortunate, as we are able to adapt. Some ski resorts have already opened mountain bike trails in winter to offer alternative tourism, but wildlife and ecosystems cannot adjust so rapidly.

In the mountains many species, such as ptarmigan and mountain hares, change their colouring for winter to camouflage in the white snow. The timing of this change is determined by length of day – not the temperature or amount of snow. These creatures are at greater risk of being preyed on when it is warmer.

White rabbit, brown background
Mountain hares are dressed for a climate that has changed.
Mark Medcalf / shutterstock

Over the past century heat extremes in Europe have increased in intensity and frequency. Both the general warming and heatwave events have been firmly attributed to humans.

Future projections suggest these trends will continue and heatwaves in both summer and winter will get hotter, last longer, and occur more often. We need to learn to adapt for these changes in all seasons and think about the impacts on everyone – and everything – on our planet.The Conversation

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This blog is written by Cabot Institute for the Environment members Dr Vikki Thompson, Senior Research Associate in Geographical Sciences, University of Bristol and Dr Hannah Bloomfield, Postdoctoral Researcher in Climate Risk Analytics, University of BristolThis article is republished from The Conversation under a Creative Commons license. Read the original article.

India heatwave: why the region should prepare for even more extreme heat in the near future

An extreme heatwave in India and Pakistan has left more than a billion people in one of the most densely populated parts of the world facing temperatures well above 40℃. Although this has not broken all-time records for the regions, the hottest part of the year is yet to come.

Though the heatwave is already testing people’s ability to survive, and has led to crop failures and power blackouts, the really scary thing is that it could be worse: based on what has happened elsewhere at some point India is “due” an even more intense heatwave.

Together with a few other climate scientists, we recently looked for the most extreme heatwaves globally over the past 60 years – based on the greatest difference from expected temperature variability in that area, rather than by maximum heat alone. India and Pakistan do not feature in our results, now published in the journal Science Advances. Despite regularly having extremely high temperatures and levels of heat stress in absolute terms, when defined in terms of deviation from the local normal, heatwaves in India and Pakistan to date have not been all that extreme.

In fact, we highlighted India as a region with a particularly low greatest historical extreme. In the data we assessed, we didn’t find any heatwaves in India or Pakistan outside three standard deviations from the mean, when statistically such an event would be expected once every 30 or so years. The most severe heatwave we identified, in southeast Asia in 1998, was five standard deviations from the mean. An equivalent outlier heatwave in India today would mean temperatures of over 50℃ across large swaths of the country – such temperatures have only been seen at localised points so far.

Our work therefore suggests India may experience even more extreme heat. Assuming the statistical distribution of daily maximum temperatures is broadly the same across the world, statistically a record-breaking heatwave is likely to occur in India at some point. The region has not yet had reason to adapt to such temperatures, so may be particularly vulnerable.

Harvests and health

Although the current heatwave has not broken any all-time records, it is still exceptional. Many parts of India have experienced their hottest April on record. Such heat this early in the year will have devastating impacts on crops in a region where many rely on the wheat harvest both to eat and to earn a living. Usually, extreme heat in this area is closely followed by cooling monsoons – but these are still months away.

It is not just crop harvests that will bear the brunt, as heatwaves affect infrastructure, ecosystems and human health. The impacts on human health are complex as both meteorological factors (how hot and humid it is) and socioeconomic factors (how people live and how they are able to adapt) come into play. We do know that heat stress can lead to long-term health issues such as cardiovascular diseases, kidney failure, respiratory distress and liver failure, though we will be unable to know exactly how many people will die in this heatwave due to the lack of necessary health data from India and Pakistan.

What the future holds

To consider the impact of extreme heat over the next few decades, we have to look at both climate change and population growth, since it is a combination of the two that will amplify the human-health impacts of heat extremes in the Indian subcontinent.

world map with some countries shaded yellow
Hotspots of population increases over the next 50 years (red circles), all coincide with locations where no daily mortality data exists (yellow).
Mitchell, Nature Climate Change (2021), CC BY-SA

In our new study, we investigated how extremes are projected to increase in the future. We used a large ensemble of climate model simulations, which gave us many times more data than is available for the real world. We found that the statistical distribution of extremes, relative to a shift in the underlying climate as it generally gets warmer, does not change. In the climate models the daily temperature extremes increase at the same rate as the shift in the mean climate. The IPCC’s latest report stated that heat waves will become more intense and more frequent in south Asia this century. Our results support this.

The current heatwave is affecting over 1.5 billion people and over the next 50 years the population of the Indian subcontinent is projected to increase by a further 30%. That means hundreds of millions more people will be born into a region that is likely to experience more frequent and more severe heatwaves. With even larger numbers of people being affected by even greater heat extremes in the future, measures to adapt to climate change must be accelerated – urgently.The Conversation

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This blog is written by Cabot Institute for the Environment members Dr Vikki Thompson, Senior Research Associate in Geographical Sciences, University of Bristol and Dr Alan Thomas Kennedy-Asser, Research Associate in Climate Science, University of Bristol.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Violence and mental health are likely to get worse in a warming world

As heat levels increase, mental health conditions are likely to worsen.
Pxfuel

Extreme weather has been the cause of some of the biggest public health crises across the world in recent years. In many cases, these have been enhanced by human-induced climate change. For instance, in 2003, high summer temperatures in Europe were believed to cause 50,000 to 70,000 excess deaths across 16 European countries.

Globally, it’s been estimated that a total of 296,000 deaths over the past two decades have been related to heat.

But heat doesn’t just affect physical health. It can have equally serious effects on mental health conditions. Research has shown that rising temperatures are associated with an increase in suicides and in violent behaviour, as well as exacerbating mood and anxiety disorders.

Studies in England and Wales conducted between 1993 and 2003 have revealed that, when temperatures were above 18°C, every 1°C rise in temperature was associated with a 3.8% increased risk of suicide across the population.

Between 1996 and 2013 in Finland, every 1°C increase in temperature accounted for a 1.7% increase in violent crime across the country. It has even been estimated that 1.2 million more assaults might occur in the United States between 2010 to 2099 than would without climate change.

The association between high temperatures and mental health is an active area of research. Scientists have found that some health consequences of increased heat, like disturbed sleep and levels of serotonin – a hormone critical for adjusting our feelings, emotions and behaviours – might play a role in triggering the appearance of mental health conditions.

A world map coloured red, with darker areas indicating greater temperature rises (up to 6°C).
This map shows the projected changes in daily temperature extremes at 1.5°C of global warming compared to the pre-industrial period (since 1861).
Author provided

Sleep deprivation often occurs during heatwaves, which then may lead to frustration, irritability, impulsive behaviours and even violence.

Extreme temperatures, such as those observed during heatwaves, are also found to be associated with some forms of dementia and disturbed mental health states, especially for those who are already in vulnerable conditions such as psychiatric patients.

And low levels of serotonin are associated with depression, anxiety, impulsivity, aggression and occurrence of violent incidents.

Implications

In the future, heatwaves will be hotter and last longer. Temperature records are likely to be broken ever more frequently as the world continues to warm. In north-west Asia, for example, temperatures could increase by 8.4°C by 2100.

A world that is on average 1.5°C warmer will see many average regional temperatures rise by more than this. This problem is compounded as the population – and therefore the number of people living in cities – increases. By 2050, it is projected that two thirds of the world’s population will live in urban areas.

A city in summer
Cities are often hotter than rural regions, exacerbating negative mental health effects caused by heat.
PedroFigueras/Pixabay

Urban environments are known to be warmer than their rural surroundings, a phenomenon known as the “urban heat island”. Climate projections show not only that cities will warm faster than rural areas, but that this effect is increased at night. This may further exacerbate the effects of heat extremes on our sleep.

Both adaptation to and mitigation of climate change will be necessary to lessen these potentially devastating effects as much as possible.

Options for adapting our lives to a warmer world could include increasing air circulation within buildings and adjusted work hours in times of extreme heat. Paris, for example, has already created a network of “cool islands”: green and blue spaces such as parks, ponds and swimming pools which provide places to seek refuge from the heat.

Most simply, educating people on the potential impacts of heat on mental health, aggression and violence – allowing them to understand exactly why it is so important to support initiatives that help keep our planet cool – could support better mental health at the same time as fighting the climate crisis.

—————————————–The Conversation

This blog is written by Cabot Institute for the Environment members Dr Mary Zhang, Senior Research Associate in Policy Studies, University of Bristol; Professor Dann Mitchell, Associate Professor in Atmospheric Sciences, University of Bristol, and Dr Vikki Thompson, Senior Research Associate in Geographical Sciences, University of Bristol

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Dann Mitchell
Mary Zhang
Vikki Thompson

 

 

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