Staying on track in summer heat and winter chills 

The weather impacting travel plans isn’t anything new. But for the UK’s railways, our varied and changing climate introduces additional challenges.  

A changing climate increases the frequency of severe weather events. Warmer air can hold more water, so rainfall is increasing on average across the world. In some places, rainfall is becoming more intense as well. 

In addition, record-high temperatures are being seen more frequently. Summer 2022 saw the UK record breaking a new all-time high of 40.3°C during a heatwave when 46 stations met or exceeded the previous national record of 38.7°C. With records highs, railways in the UK also have to endure sub-zero conditions in the winter, and even high-impact storms.  

Image: Shutterstock

During Storm Eunice in February 2022 – which struck during a week of three named storms – cancellations on the rail network was at 44.1%. 

The Office of Rail and Road (ORR) is the independent regulator responsible for safety monitoring on Britain’s railways; an area of the UK’s travel infrastructure that can be sensitive to variations in the weather.  

ORR’s role for Britain’s railways involves working with train operators to ensure safety procedures are being followed and that people can get around safely on Britain’s trains, whatever the weather.  

Paul Appleton is Deputy Director of Railway Safety at ORR and his team is busy working with operators through the winter season. He said: “Temperature range is a very interesting issue when it comes to the ability of Britain’s railways to run safely. 

“At the cold end of the spectrum, the steel on our railways contracts, which can put them under massive tension and expose any underlying flaws. When it gets hotter, the steel expands and if it gets to extreme levels of heat then that expanding rail will risk buckling and possibly derailing a train.” 

In 2022 temperature extremes weren’t hard to come by. The record maximum temperature of 40.3°C was recorded at Coningsby in July as part of a severe and widespread heatwave. At the other end of the scale, -17.3°C was the lowest temperature recorded in 2022, in Aberdeenshire in December. Train operators are often forced to impose speed restrictions to mitigate risks at either end of the spectrum.  

Part of ORR’s remit is to ensure train operators have the processes in place to manage variations in temperature; something that can be traced back to selecting the type of steel used for Britain’s railways. 

Paul said: “Rail temperature is very different to air temperature and there’s an operable range for steel railways. You can design your steel to work within a certain range, but you can’t extend that range. If you want the railways to be able to withstand 40°C summer heat, you’ll lose some of its reliability in lower temperatures during the cold winter months.” 

Winter weather 

As cold winter weather has come back into force in recent days, ORR’s focus has shifted towards low temperatures, snow, ice and the possibility of named storms.  

“With snow, the problem is pretty obvious. If there is enough of it, it blocks the railway. With ice, there’s a risk of it forming on the 3rd rail which can prevent trains from drawing sufficient power,” said Paul.  

Image: Shutterstock

Fortunately, rail operators, much like the public at large, take preventative action to mitigate the impacts of severe weather.  

In the early hours of the morning, while much of the country is still sleeping, trains take to tracks all over the country clearing leaves from the line and de-icing the surface of the 3rd rail.  

“Leaves on the line can be a big issue at this time of year. When trains run over leaves on a track, it creates a poor adhesion environment, where trains – which are obviously very heavy – struggle to get the friction required to move and stop efficiently.  

“Just one way that risk is managed is with trains being sent out with high pressure jet washers to keep leaves off the line and ensure trains have the best possible contact with the track. This will often also include applying a substance to improve grip.” 

According to Rail and Standards Board figures, poor adhesion costs the rail industry and wider society an estimated £355million every autumn. The Met Office works with many leaf adhesion services to help improve efficiencies throughout the year.  

Be prepared 

Tracks have an operable temperature range which can be sensitive in a UK climate. (Image: Shutterstock)

With steps taken to prepare railways ahead of severe weather, the public also have a role to play in keeping Britain’s railways running smoothly.  

For ORR, a ‘severely disrupted day’ of rail travel is when cancellations are at 5% or more. During Storm Eunice on 18 February, that rate was at 44.1%.  

Paul says the preparedness of the public for severe weather can help mitigate the disruption on days of severe weather.  

“After a storm, debris on the line is one of the leading causes of ongoing disruption to rail services. Of course, some of this is down to fallen trees, but we also get a lot of garden furniture and trampolines on the tracks which all has to be dealt with before services can fully resume.  

“Taking some time ahead of a storm to check for things that could be blown away would help and could also prevent delays on roads as well. 

“If you’re looking to travel after a storm, take some time to check your train operator’s website to see if there are likely to be any issues. It’s thanks to the Met Office that they know when weather conditions will be impactful enough to disrupt operations, so do also check the Met Office website or App ahead of travel.” 

The Met Office’s WeatherReady website brings together seasonal advice from expert partners  to help you stay safe and make the most of the weather all year round. WeatherReady provides simple preparedness tips anyone can do to help them prepare ahead of severe weather.

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The temperate rainforests of Dartmoor

Last week, Dr Debbie Hemming, Scientific Manager of the Met Office Vegetation-Climate Interactions (VCI) group, took part in filming and podcast recording for the Sky Climate Show on the subject of temperate rainforests. Here, Debbie explains why she is so interested in temperate rainforests and why they are an area of scientific research.  

It might sound strange, but contrary to belief we do have rainforests here in the UK. Indeed, you don’t have to travel far from our Exeter HQ to find them. Nestled in isolated pockets along the moisture-laden west coasts of the UK and Ireland are fragments of lush ancient woodland that belong to the ecological group known as Coastal Temperate Rainforest.

Although these habitats occur in other locations around the world, they are limited to small, isolated pockets and are therefore considered rare and threatened by changes in climate, land use and associated impacts, such as wildfires or pests and diseases.

I was recently approached by Tom Heap from the Sky Climate Show who was interested to learn more about these fascinating ecosystems, why they are important and how they might be at risk from climate change.

We met at a spot almost right in the middle of Dartmoor on a suitably wet and windy morning and walked a short distance to find one of these magical locations.

Dr Debbie Hemming being interviewed by Tom Heap for the Sky Climate Show. Image: Met Office

Temperate rainforests are fascinating, diverse ecosystems. In the UK, they occur in isolated areas with at least 1,500mm of rainfall each year, although in Scotland this can be over 4,000 mm per year which is more than in many tropical rainforests. The ecosystems are characterised by oak trees, often stunted and contorted by the extreme conditions, interspersed with hazel, birch, rowan, ash and holly trees.

Covering everything in sight are vibrant green mosses and diverse lichen, which further support a community of ferns and other epiphytes. Various species of small animals, birds and insects are attracted to the benefits that these habitats provide.  The abundance of mosses and lichen also indicate a requirement for clean air.

As well as being a landscape that can benefit wellbeing, temperate rainforest ecosystems provide us other services. By supporting flora and fauna that wouldn’t otherwise survive in these areas they increase the biodiversity of the region and provide a carbon sink that would not otherwise exist. They also play a role in flood control by slowing the transport of intense rainfall to the rivers.

However, with our changing climate and continued pressure on land use, the risks to temperate rainforests are likely to increase. We expect to see more weather and climate extremes as a consequence of our warming climate. Further hot, dry spells could threaten these habitats as they rely on high levels of rainfall and humidity to function. Increases in wildfires could also pose a risk to the small patches of land occupied by temperate rainforests.

It’s therefore important for scientists to understand the changes that climate extremes and trends are likely to have on temperate rainforests, and indeed other habitats around the world, in order to provide scientific advice to support their sustainable management into the future.

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Changing climate brings impacts for hay fever sufferers 

For this month’s climate theme, we are focusing on health. In this blog post, we’re discussing pollen, the impacts that it can cause for hay fever sufferers, and whether a changing climate will influence pollen levels throughout the year.  

Pollen and hay fever 
Respiratory allergies are more common than ever, and recent studies in Europe have found that some pollen types are increasing in severity, season duration and seeing an earlier onset as a result of climate change. 
Pollen is made up of tiny particles which are released by plants and trees as part of their reproductive cycle. When inhaled, pollen can cause significant irritation and inflammation in people or animals who are allergic to it.  

Hay fever symptoms usually appear when the pollen count reaches moderate or high, depending on the individual’s sensitivity to the pollen allergens. 11% of UK adults suffer from severe hay fever and common symptoms include sneezing, runny or blocked nose, and itchy eyes, mouth and throat. 

How weather and the seasons affect pollen levels 
Rain, wind, temperature and sunshine all affect how much pollen will be produced and how much it will be dispersed. On warm, dry days with gentle to moderate winds, pollen spreads easily but on rainy days, pollen can be cleared from the air. On sunny days, the pollen count is highest in the early evening which is therefore when you are most likely to suffer from hay fever symptoms. 

Seasonality and pollen 

As well as the weather at the time of pollen dispersal, there are seasonal weather patterns that change things. We know that, on a daily basis, any rainfall decreases pollen, but a warm spring with sufficient rain will allow for good pollen production in grasses and the potential then for high summer pollen counts.

Conversely, very dry weather in spring suppresses pollen production in grasses, reducing the potential, and very hot and dry weather actually prevents grasses from growing at all. For tree pollen, the production occurs in the catkins in the previous summer and if June and July are very warm, then there will be more pollen produced. This is happening more frequently due to climate change increasing the summer temperatures. 

The influence of climate change on UK seasons 

The UK has a temperate maritime climate which means that we generally have a cool and mild climate with changeable weather. As a result of climate change however, we can expect to see some changes to the weather we see in the UK. In the future, whilst we will still see a lot of the same weather that we experience today, the intensity of some weather types will change. Across the UK, we are already seeing and expect that we will continue to experience: 

  • Warmer and wetter winters 
  • Hotter and drier summers 
  • More frequent and intense weather extremes 

Research to explore the climate change/pollen link

A recently conducted study looked at pollen trends in the UK over the last 26 years to better understand the relationship between these trends and meteorological factors.  Led by the University of Worcester, the study examined a range of UK pollen sites, with a focus on the key pollen types: grass, birch and oak.  

The results of the study revealed a somewhat mixed picture of how different types of pollen are affected by climate change. One of the key findings was the fact that oak and grass pollen seasons are starting earlier, and the birch season is getting more severe. The study also highlighted how increasingly unusual weather – as a result of climate change – coincided with increasingly erratic pollen seasons. It was also noted that a trend to lower wind levels is reducing dispersal of grass pollen grains in the summer. 

Dr Beverley Adams-Groom, senior pollen forecaster at the University of Worcester and lead author of the study, said: “Climate change is impacting on seasons. It’s difficult to predict the long-term future as there are many factors at play. What we do know is that there are going to be more extreme weather events – that’s documented, and that can impact on the seasons.” 

The future? More pollen unpredictability

Whilst the study findings may not indicate a drastic influence from climate change in terms of increasing pollen levels, what is clear is that if the current climate trajectory remains the same, the trends that have been identified are expected to continue. 

Climate change will very likely cause increasingly erratic and unpredictable seasons and weather patterns. The biggest defence for hay fever sufferers is to be prepared, something which these changes caused by climate change will make more difficult.  

We are already seeing the impacts of climate change, including on pollen, and change will continue to occur. We can still mitigate against the worst impacts, however, by rapidly reducing emissions.  

In addition to our daily weather forecasting services, we provide pollen forecasts for five days ahead across the whole of the UK during the pollen season. These forecasts are produced by combining data from the pollen count monitoring network with Met Office weather data and expertise from organisations such as the National Pollen and Aerobiological Unit. You can learn more about our pollen forecasts and find advice on preparing for and managing the symptoms of hay fever on our website 

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Heat in cities – the health impacts of a changing climate

Health is already impacted by the weather, with heat in particular causing heat-related illnesses, exacerbating existing heath conditions and excess deaths. In a changing climate, these impacts can be expected to increase. Urban areas are particularly vulnerable to changes in heat and as more people move into urbanised areas, it is important to understand how extreme heat will affect health and how these impacts can be minimised.

Extreme heat

Last year, the UK experienced an unprecedented heatwave in July, where temperatures exceeded 40°C for the first time. This was a milestone in UK climate history, which was complemented by the first ever red severe weather warning for heat issued by the Met Office. Some areas of southern England recorded their highest ever temperatures by extraordinary margins of 3-4°C.

A Met Office study has recently been supported by the World Weather Attribution, which found that the likelihood of seeing 40°C in the UK has been ‘rapidly increasing’ and what once would have been an extremely unlikely event without climate change, has now become an unmistakable possibility. Both studies found that human induced climate change has made the chance of 40°C in the UK about 10 times more likely when compared with pre-industrial levels.

According to an analysis by the Office of National Statistics, from 10-25 July 2022, spanning the dates encompassing the new record temperature was hit, excess deaths were 10.4% above average for that period. This short-term increase in mortality is common during heatwaves. For example, the 2003 heatwave accounted for over 2,000 excess deaths in the UK: and in 2019 a heatwave which caused temperatures in England to reach 38.7°C caused 892 deaths. Direct increases in mortality and morbidity are usually amongst the most vulnerable groups which include people aged 75 years and over, infants and those with chronic medical conditions. These effects can be expected to increase especially among the elderly as the demography of the population shifts to include an increasing proportion of old-age citizens. High temperatures can also lead to an increase in heat-related illnesses such as heat stroke and heat exhaustion. Symptoms include nausea, dizziness, muscle weakness and high body temperature.   

Urban heat island effect

Living in a city can increase vulnerability to heat. Many deaths during heatwaves occur because of the combined effect of high temperatures and the urban micro-climate. In addition to background warming an additional factor facing city residents is the urban heat island effect. Buildings absorb rather than reflect the sun’s heat, and waste heat from air conditioners and vehicles can add warmth to the surroundings, increasing temperatures. Additionally, tall buildings and narrow streets reduce wind speeds, and the removal of trees reduces the natural cooling effect of shading and evaporation. Air pollution can also cause the effect of a micro greenhouse gas layer, stopping heat from radiating back into the atmosphere.

As more people move to urban areas in the UK, more people will become vulnerable to changes in climate and extreme weather events. Heat risks in urbanised areas can be minimised by utilising the amount of green space available, for example by planting trees in open spaces and in the streets. Heat reduction policies and rules could also be put into place at a local level.

Raising awareness

It is also important that local communities are educated about the risks associated with heat. Four in ten adults in England think heatwaves are “a normal part of summer”1 and have positive views about hot weather. Most people do not see heatwaves as a threat so are less likely to take protective measures. Additionally, most people in England do not consider themselves as at risk from the heat, even those from high-risk groups including elderly adults ages 75 and over. If the impacts of heatwaves that are posed by climate change are not clear, people are more likely to be exposed to the risks. It is important that people understand the real dangers of extreme heat and prepare for this, particularly as the climate changes and these events become more frequent, intense and of longer duration.

Utilising climate information for adaptation

Cities therefore need to be informed by the latest climate research and observational data to increase their ability to adapt to climate change and minimise these risks. At the Met Office, our Urban Climate Services team have created Heat Packs which consist of fact sheets containing information about how extreme heat events may change this century due to climate change. The Heat Packs have currently been generated for Bristol, Belfast and Hull. This work has also been combined with socio-economic data to understand which areas are more vulnerable to heat risks within the city. These Heat Packs can be used to understand the risks of heat in particular cities so that these areas can be better prepared against extreme events as we make our way into an uncertain future. This is supported by the Climate Programme Manager from Belfast City Council who said, “The Belfast Heat Pack is an important resource for Belfast and is being used to support both city and council climate planning and the development and delivery of climate projects such as the UPSURGE project and Belfast One Million Trees Project. We need to understand the impacts of heat on the city and on our residents as we plan for future climate changes and the Heat Pack is extremely helpful in supporting that”.

1. British Red Cross, (2021). ‘Feeling the heat: a British Red Cross briefing on heatwaves in the UK’. [online] Available at: Feeling the heat: a British Red Cross briefing on heatwaves in the UK | British Red Cross

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Climate change and health

Climate change affects our daily lives. The climate influences the type of food we grow and eat; water availability; the way we cool our homes; and deciding where to build new accommodation for a growing and moving population. Cross-cutting all of these themes, linking climate change with food, water, sanitation, shelter and migration, is health. Ahead of the UN’s Climate Conference, COP27, in November 2022, WHO highlighted the need for urgent climate change action for health.

Climate-related health risks

Professor Dann Mitchell, Professor of climate science at the University of Bristol, explains that “Weather and climate are already impacting health; even as far back as the infamous 2003 European heatwave we know that around half the deaths could have been avoided if climate change had been halted.

“To fully understand the health impact of climate change, we must consider the exposure across short- and long-time scales. At one end of the spectrum daily extreme temperatures act immediately on the cardiovascular system, at the other end, decades or persistent warm nights act on the cognitive system”.

Risks from a changing climate include an increase in heat-related illness, respiratory illness, mental health problems and vector-borne diseases, such as dengue or malaria. Whether a disease is passed through the air, water or carried by insects, the impacts of climate and extreme weather increase the risk.

As with other climate-related risks, the most vulnerable in society are likely to be the most impacted, whether that be people with underlying health conditions or those living in developing countries where climate impacts might be greater and/or healthcare provision may be less advanced.

Image showing stethoscope and medical book.
Image: Shutterstock

Mitigate and adapt

Whilst we are already seeing the effects of our changing climate, there is still time to mitigate against the worst impacts by rapidly reducing carbon emissions. This also has additional co-benefits such as reduced air pollution which is a serious public health problem. The University of Leeds, working with the Met Office, developed a new tool for policymakers, academics and industry to see how single actions can have multiple benefits for people’s lives, including on health.

Adapting to the changes we are already seeing and will see in future, will also make society and individuals more resilient to the health impacts of climate change. This can include making sure people are aware of immediate risks, such as through severe weather warnings – the Met Office introduced a new severe weather warning for heat in 2021, reflecting the fact that the UK can expect more extreme heat as a result of climate change. Adapting homes and buildings as well as healthcare provision will also be vital to tackle climate change impacts.

During January, we will be exploring the theme of climate change and health, looking at some of the ways our health could be impacted and sharing research from the Met Office and our partners to better understand the risks and tackle the issues. Follow #GetClimateReady on Twitter to find out more.

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What’s driving the UK weather this January?

Weather headlines have been in demand in recent weeks, with a recent deep freeze in North America taking wind-chill temperatures as low as -48°C and much of Europe seeing in the new year with record-breaking mild weather for at least eight countries. 

However, despite the noteworthy weather in recent weeks and days to the east and west of the UK, a more typical winter weather pattern is most likely in January, with a number of factors driving an unsettled outlook.  

Recent cold in North America

Although the coldest conditions have now relented in North America, the temperature contrast had been helping to invigorate the jet stream, which is the driving force behind much of the UK’s weather.  

Met Office Deputy Chief Meteorologist Rebekah Sherwin said: “The temperature drop in North America before the end of 2022 was the underlying cause of our wet and windy weather in the run-up to New Year. The conditions across the Atlantic served to strengthen the jet stream and help send low pressure systems and weather fronts towards the UK, resulting in the recent unsettled conditions.  

“Those incredibly low temperatures have now passed in North America and there will not be any direct impacts from that period of weather on the UK in terms of any potential snowfall events.”

A snowy street in North America.
North America has seen some impactful snow and ice in recent weeks (Image: Shutterstock)

Mild Europe

Exceptionally high temperatures have started the year for much of Europe with Poland, Denmark, the Czech Republic and Belarus, among others, already having recorded their warmest January day on record.  

In Brest, Belarus, temperatures would normally be around 0°C at this time of year but reached a balmy 15.9°C on New Year’s Day, eclipsing its previous January record by a considerable margin. 

The driving force behind this exceptional heat was a warm air mass from the west coast of Africa, which moved across Europe, bringing unseasonably warm conditions.  

Rosie Oakes is a Climate Scientist at the Met Office. She said: “Although this specific event can’t be attributed to climate change without a formal study, the increases in average global temperatures caused by human activities such as burning fossil fuels makes it more likely that temperature records will be broken.  

“What’s noteworthy about this event is how widespread it is as well as the amount previous records have been exceeded by. Climate models projects that both the frequency and intensity of these warm weather events will increase in the future, not just in the summer but in the winter too.” 

An image of Brest, Belarus in mild conditions.
Brest, Belarus, eclipsed its January temperature record by a considerable margin (Image: Shutterstock)

Has this had an impact on the UK outlook?

The influence of the North American Christmas cold weather on the strength of the jet stream has now passed. However, other cold air outbreaks across North America and the Pacific, both recent and upcoming, are likely to affect North Atlantic jet streams in a similar fashion in the coming days. This means a continued wet and windy outlook for the UK, at least through the first part of January, with weather systems likely to impact the UK from the west.   

Another underlying factor behind the UK long-range outlook is the ongoing La Nina event, which sees episodes of cooler than average sea surface temperature in the equatorial Pacific. This can often lead to a drier and cooler first half of winter, before a transition to more unsettled conditions in January and February, with frequent wind and rain moving into the UK from the west.  

Rebekah Sherwin added: “A westerly regime is most likely for the UK in the first part of January, which means wet and windy conditions for many. Rain or showers will often be heaviest and most frequent in the west and northwest but areas further south and east are by no means immune. Temperatures are expected to be near or above average overall, with any sleet or snow most likely restricted to high ground in the north. 

“Towards the middle of the month there are some indications that the jet stream will weaken, which may be related to current and upcoming patterns of thunderstorm activity in the tropics. This may well lead to less unsettled conditions developing for a time, with an increased chance of colder, drier spells for many parts of the UK, although there aren’t currently any significant signs of long-lasting cold weather.” 

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Cold December concludes warmest year on record for UK 

NOTE: This blog has been updated on 3 January to include the full provisional statistics for December 2022.

A cold December bucked the trend of 2022 and ended the year as the only month which saw below-average temperatures, according to provisional Met Office figures.  

With 2022 provisionally confirmed as the UK’s warmest year on record for the UK December ended a 15-month run of above average temperatures (from September 2021) with an overall cool, dry and sunny month for the UK compared to 1991-2020 long-term averages.  

Mostly cold and dry

The first two weeks of December were the coldest start to meteorological winter since 2010, with high pressure and a cool northerly airflow resulting in a prolonged spell of low temperatures with snow and icy conditions at times, albeit with interludes of clear skies.  

A weather station at Braemar, Aberdeenshire, recorded the lowest daily maximum temperature of the year, with -9.3°C the highest it reached on 12 December. In the early hours of the following morning, the same station recorded the lowest minimum temperature of the year with –17.3°C.  

The cold snap ended with a dramatic change to much milder conditions bringing widespread thaw conditions. Temperatures for the remainder of the month were mostly above average for the time of year, though December overall will still go down as a cool month for the UK with the average mean temperature at 2.9°C, which is 1.3°C cooler than the 1991-2020 average.  

Map of the UK with December's mean temperature against long term averages. The map shows a cooler than average month for the UK.
December 2022 mean temperature

Those cool conditions were replicated across the UK with England, Wales, Scotland and Northern Ireland all seeing temperatures around 1.4°C lower than their average for the month, though not cold enough to trouble any records. For comparison, December 2010, the UK’s coldest December on record in a series from 1884, was an exceptional 5.1°C colder than the 1991-2020 average. 

Mike Kendon is a climate information scientist working for the National Climate Information Centre in the Met Office. He said: “December’s weather will principally be remembered for the notably cold start to the month, with prolonged low temperatures, hard frosts and snow and ice at times, even to areas further south in the UK.  

“This cool weather was principally brought on by an Arctic Maritime airmass, with daytime temperatures struggling to rise above freezing for many in what was one of the most significant spells of low winter temperatures since the exceptional December of 2010.” 

Cold weather and climate change

Although the UK will continue to experience a number of cold spells of weather, the frequency, severity and durations of these temperatures has declined as a result of climate change, as can be seen in observational data and as part of a post-event report on early December’s low temperatures.

Graph showing the number of days per year with UK mean temperature below "C and below 0C. The graph shows a declining trend.

The graph’s blue and red lines show the number of days in each calendar year from 1960 when the UK-wide mean temperature was below 2°C and 0°C respectively, with the hatched lines showing a downward trend.  

Mike Kendon added: “Such is the variability of the UK climate, we’ll always experience cold weather. However, what our observed data shows is the decreasing prevalence and severity of these events in a changing climate. Using 30-year climate averaging periods from 1961-1990 and 1991-2020, the number of days where mean temperature for the UK was below 2°C has decreased by a third within this thirty-year period, and the number of days below 0°C has halved. These are dramatic changes. 

“The fact that we’ve seen the warmest year on record for the UK in 2022 despite the cold December weather demonstrates how persistently warm the rest of the year was, with every season’s mean temperature sitting in its top 10 on record in a series which goes back to 1884.”

Dry December

Map of the UK showing rainfall amount in December 2022 versus long term averages. The map shows a mainly dry month for the UK, albeit nearer average further south.
December 2022 rainfall amount

Despite late-month rainfall bringing figures up, December remained drier than average for the UK. With milder Atlantic air and associated rain-bearing fronts blocked during the cold spell, there was little precipitation overall across many parts of the UK for the first half of the month.  

The UK had 111mm of rain in December, which is 87% of the average.  

Northern Ireland has been the driest of the UK regions, with 89.1mm of rain in the month putting it at around three quarters (74%) of what you’d expect in December. England saw 89.3mm (97% of average) and Wales 165.3mm (94% of average).  

Sun shines for most

A map showing the UK's sunshine amount for December 2022 versus the long term average. The map shows a mainly sunnier than average month, though the north of Scotland had fewer sunshine hours than average.
December 2022 sunshine hours

High pressure and clear Arctic air resulted in plentiful clear skies to be found in December, with the exception of northern Scotland, and the UK seeing 16% more sunshine hours than average.  

Western areas generally saw more in the way of sunshine, but the vast majority of the UK has had a bright, albeit cold, month of weather. Northern Ireland has seen more than a third more sunshine hours than average (134% of average), Wales 24% more than its average and England 17% more than its average. Scotland will end the month with near-average figures for sunshine.  

Provisional December 2022Mean temp (°C) Sunshine (hours) Rainfall (mm) 
 Actual Diff from avg (°C)Actual% of avgActual% of avg
UK 2.9 -1.3 49.4116  111.0 87
England 3.5 -1.3 59.7117 89.3 97
Wales 3.4 -1.4 51.0124 165.3 94
Scotland 1.6 -1.4 31.4105 136.6 79
N Ireland 3.4 -1.3 51.2134 89.1 74
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Reflection of a sustainable ‘grand oasis’ in space

Met Office scientist Nick Dunstone reflects on the latest ‘Earthrise’ image captured recently by Artemis 1 and how our climate has changed in the 54 years since Apollo 8 took the original iconic photo.

“Oh my God! Look at that picture over there! There’s the Earth coming up. Wow, that’s pretty,” said NASA astronaut Bill Anders’ when seeing the Earth appearing to rise above the lunar horizon as their Apollo 8 spacecraft came around the moon on Christmas Eve 1968.

It was a unique vantage point: the first-time any human had seen our planet at such a distance, and from another celestial body.

As fellow astronaut Jim Lovell said a few hours later: “The Earth from here is a grand oasis in the big vastness of space.”

Images: NASA

That original Earthrise image is widely credited with helping to set the mainstream environmental movement in motion. Although I wasn’t born when the original Apollo 8 photo was taken, a framed print of it hangs above my desk as a reminder of the beauty and fragility of our planet.

Artemis is the new NASA programme to return humans to the Moon and then beyond to Mars. Artemis 1 is the unmanned test flight before the crewed Artemis 2 mission in 2024, and so there was no one scrambling to find the colour film for this new image. Much has changed since 1968, and I wanted to reflect briefly on the changes to our planet between these two beautiful images, taken 54 years apart.

Firstly, there are a lot more of us on the planet now. This year we passed the 8 billion global population milestone, meaning the number of people on the planet has more than doubled from the ~3.5 billion in 1968. Half a century of continued industrial development – driven primarily by burning fossil fuels – has led to a rapid increase in the concentration of carbon dioxide (and other greenhouse gases) in our atmosphere.

This is clearly illustrated by the iconic ‘Keeling curve’, which plots the continuous record of atmospheric carbon dioxide from Mauna Loa Observatory in Hawaii (started by Charles Keeling in 1958).

This curve, shown below, shows a steep and steady upwards trajectory, increasing from ~320 ppm in 1968 to almost 420 ppm in 2022 – that’s a 100 ppm (31%) increase – with no sign yet of slowing down.

Observed timeseries of atmospheric carbon dioxide concentration and global mean surface temperature with added logos for the Apollo 8 and Artemis 1 missions. For latest updates on these and other key climate change indicators, visit the Met Office climate dashboard.

This additional ‘blanket’ of greenhouse gases has increased the surface temperature of our planet. The World Meteorological Organisation (WMO) global temperature record is plotted above and made from five different analyses of global temperature data, including the Met Office’s own HadCRUT5. It shows the Earth’s surface has warmed by approximately +1°C since the Apollo 8 Earthrise photo was taken.

Given that current global temperature is +1.2°C above the pre-industrial 19th Century climate, we can see that by far the most of this warming has occurred in the last half century. Whilst an average global temperature increase of +1°C may not sound large, it means that extreme hot climate events are much more likely. For example, the UK experienced another very warm summer this year placing it amongst the hottest five summers on record, with four of those five having occurred since 2000. 

During this summer, the UK experienced a new daily maximum temperature record, when 40.3°C was recorded at Coningsby, Lincolnshire on 19 July. This is the first time that 40°C has been recorded in the UK, and Met Office research has estimated that this event is as much as 10 times more likely in the current climate than under a natural climate unaffected by human influence.

There is an enduring legacy of the technologies developed during the mid-20th century space race that have transformed our ability to understand, monitor and predict changes to our climate. Thanks to the many Earth observation satellites launched in the past half century we now have continuous monitoring of many key components of the climate system, including sea-surface temperature, sea level, polar sea-ice extent, glaciers and land-surface changes.

Unfortunately, many of these reveal worrying trends, such as increased frequency of terrestrial and marine heatwaves, Arctic sea-ice loss, glacial retreat, ice sheet mass loss, deforestation of tropical rainforests and relentless sea-level rise. The other technological ‘quantum leap’ since 1968 is the enormous increase in computing power that allows us to simulate the global climate system.

By combining improved Earth observations and climate models run on powerful supercomputers, we can seamlessly predict global weather and climate from hours to centuries. Thanks to these efforts our understanding of the global mean climate response due to rising greenhouse gases is now mature and provides clear evidence for the mitigation pathways needed to avoid dangerous levels of climate change.

However, one of the key remaining challenges in climate science is understanding the detailed dynamical changes that will drive regional climate change. For example, the regional changes in monsoon systems and the mid-latitude jet streams are still uncertain with a large spread in their projected changes between different climate models.

Recent work – led by Met Office scientists – has used seasonal to decadal climate predictions, which are on timescales short enough to be verified, to identify that current climate models have spuriously weak signals in extratropical circulation. Whilst we do not yet fully understand the cause of this issue, we are becoming increasingly aware that such large-scale dynamics is connected via feedback loops to small-scale processes, such as transient eddies in the atmosphere, air-sea interactions and intense local convection.

Many of these physical features are not explicitly simulated at the relatively coarse resolutions (~50-150 km grid spacing) of the current generation of climate models that are used to make decadal to centennial climate predictions. Therefore, we are now striving as a community to push towards higher-resolution global climate models where these processes can be modelled more fully; allowing us to better quantify the regional responses to climate variability and change. To enable us to start running such models we are taking advantage of more powerful supercomputer facilities and optimising our climate models to make best use of them.

Looking ahead, I hope that by the time astronauts take the first Earthrise photo from Mars (perhaps in the mid to late 2030s), we as a global society are making good on our carbon emission reduction pledges. Then, as we head towards net-zero carbon emissions, the Keeling curve will be starting to level-off and global temperature will have begun to stabilise. Achieving net-zero is this century’s ‘Moonshot’ and the prize is minimising the severity of the worst of the projected climate impacts of global heating (including heatwaves, droughts, floods, sea-level rise) and hence leaving our children, and future generations, with a sustainable ‘grand oasis’ in space.

Nick Dunstone’s work at the Met Office includes the global temperature forecast. The forecast for 2023 has been published here.

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Improving habitat resilience in Devon

Devon has long supported a rich diversity of important habitats and species. However, many of these habitats have experienced significant declines in recent years. Much of the Devon landscape has been simplified as a result of the focus on commercial agriculture, forestry, and urbanisation.  

The loss of habitats and species has been considerable. Arguably Devon’s most important habitat, Culm Grassland, declined in extent by 50% between 1984 and 1990. During this period more widespread habitats such as hedges declined by 20% and alarmingly only 41% remain in good condition today.  

The Met Office developed the Habitat Resilience Tool for Devon as a joint venture with the Devon Wildlife Trust (DWT) in 2012. This has been used extensively by DWT to support their nature recovery projects across Devon. Ten years since the tool was developed, some of the people who worked on it from the Met Office and DWT look back on the development process and how the Devon landscape has changed in the years that followed. 

Supporting decision-making

The challenge was clear: to restore habitat resilience as well as the components required to secure habitats, helping them to increase in number, become larger in size and improve in quality. In order to identify habitat resilience in Devon, the team developed five indexes to represent different components that collectively influence how robust our habitats are. 

  1. Habitat status index – reflects the relative importance of the habitat. Habitats with higher status and better legal protection are given higher resilience values. 
  1. Positive management index – ranks areas across Devon by how well managed the land is. Better managed land is assumed to relate to a habitat with higher resilience.  
  1. Climate sensitivity index – the sensitivity of habitats to the effects of climate variability and climate change. More sensitive habitats are given lower resilience values; less sensitive habitats have higher resilience values.  
  1. Habitat fragmentation index – the size, shape and distance from one wildlife rich area to another affect the resilience of that habitat. The ability for species to move between habitat fragments was also incorporated. Higher resilience areas occur in larger, connected regions with high quality matrix of land in between.  
  1. Topographic index – a more varied landscape allows species to move and populations to change at a given site. This index links areas with greater variation in elevation, slope and aspect to those with higher habitat resilience. 

According to Dr Debbie Hemming and Neil Kaye from the Met Office, who worked on developing the tool, “The Habitat resilience tool has been designed to support Devon Wildlife Trust, and other land managers, to make appropriate decisions to manage our environment, such as implementing measures for species conservation or planning land use and green infrastructure activities. The tool combines Met Office expertise in plant science and geographical web tool development with knowledge and information on our environment held by Devon Wildlife Trust and Devon Biodiversity Records Centre.”  

Peter Burgess, the Director of Nature Recovery at DWT, also helped develop the tool and is the main user. He said, “The Habitat Resilience Tool has proven to be a great asset in supporting the development of large-scale nature recovery projects in Devon – from works to reconnect landscapes to threatened great horseshoe bat populations which forage over large landscapes, to targeting of focal landscapes for the restoration of internationally important Culm grasslands. The tool supports high level decisions to prioritise key landscapes for concerted conservation effort between DWT and a wide range of partners.” 

Improving habitats

Photo credit: Mike Symes, DWT

The population of Greater Horseshoe Bats (GHB) has declined by 90% in the UK during the last 100 years. Similar trends are seen across northern Europe, with Devon now a stronghold for the species. 

Another species which has flourished in Devon over the past decade is the wild beaver. This has been reintroduced as part of the River Otter Beaver Trial, England’s first wild beaver re-introduction project, pioneered by Devon Wildlife Trust. In 2022, Devon has thriving beaver populations on several rivers in addition to the River Otter, including growing beaver populations on the River Tamar and the River Taw.  

Photo credit: Mike Symes, DWT

Encouraging biodiversity

A key area of biodiversity in North Devon is the Culm Grassland, located between Exmoor and Dartmoor, which has led to many referring to it as ‘the land between the moors’. Its name refers to the predominance of Culm Grassland, a mix of purple moor grass and rush pasture. 

It is also a landscape facing enormous challenges. Many elements of modern farming do not support the financial health of the small, mixed farms that predominate in the Culm; tourism is underdeveloped and the area’s geographical isolation all means that this is a place of significant economic deprivation. The unique landscape that is so key to the economic health of the area and to people’s well-being is disappearing. 90% of the Culm’s unique habitat has been lost since 1950.

Photo credit: Mike Symes, DWT

Working in partnership

Using the Habitat Resilience Tool, DWT and other land managers across Devon are able to track and study landscapes and habitats more thoroughly and pinpoint areas which are in need of more resources.  

The success of the Habitat Resilience Tool for Devon for supporting DWT with the development of large-scale nature recovery projects in Devon has highlighted the potential for this tool to be replicated at other locations. This possibility is currently being explored for other wider Wildlife Trust areas across the UK. 

DWT will continue to use the tool to help strategically guide new and ambitious projects alongside the Devon Nature Recovery Network Map. DWT is currently exploring the feasibility of reintroducing wildcats to the South West and the tool has already informed initial landscape appraisals. 

During December we have been exploring the topic of biodiversity – follow #GetClimateReady on Twitter to learn more. 

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International collaboration ‘vital’ for space weather scientists

The borderless potential impacts of space weather means international collaboration is ‘vital’, according to Kate Brand, National Manager of the Australian Space Weather Forecasting Centre.

Kate’s team has been on a tour of space weather forecasting centres in the Northern Hemisphere and spent three days with the Met Office Space Weather Operations Centre (MOSWOC), sharing knowledge and collaborating on space weather services.

“We see the Met Office as a global standard for space weather forecasting centres,” said Kate.

“We wanted to develop our relationship with the centre here and share the way we do things and also find out how the Met Office operates and work out areas we can collaborate and build on each other’s strengths.”

Image of the Sun

Similarly to the Met Office, the Australian space weather forecasters work under the umbrella of their national meteorological service and provide a 24/7 space weather forecasting service, keeping an eye on the sun for solar flares, solar radiation storms, and coronal mass ejections which can cause geomagnetic storms on Earth.

While coronal mass ejections are responsible for the Aurora Borealis and Aurora Australis, powerful geomagnetic storms also have the potential to impact communications systems and, in exceptional circumstances, ground-based infrastructure. Forecasting for the events helps key industries take steps to mitigate the worst impacts.

It’s because of those potentially wide-reaching impacts that Kate says visits like the ones they’ve been undertaking are vital for space weather scientists.

Kate said: “It’s vital to link up with others on this. The space weather community is relatively small and there are many problems to solve. I don’t think any centre could do everything on their own so it’s important to work together globally.”

Met Office Senior Account Manager of Space Weather Krista Hammond said: “It has been great having the Australian Space Weather Forecasting Centre come to visit us at the Met Office.

“We’ve been talking through the different challenges we face in terms of forecasting for different industries, how to best communicate these messages, and how we can potentially work more closely together in the future.”

With recent news of the long-awaited Vigil mission officially getting the green light, Kate concluded that it’s a good time to see more developments in the field.

“Vigil is going to be a critical mission for future space weather forecasting capabilities going forward so we’re excited that it’s all going ahead,” said Kate.

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