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One in 250-year event underway high in the atmosphere.

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2 months ago

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For the first time since records began in the mid 20th century , this extended winter period (November to March) is the first in our observational records to see three Sudden Stratospheric Warming (SSW) events. Met Office research suggests the likelihood of having three SSW events in one winter period is just a one in 250-year chance, although it is more likely to happen during an El Niño winter, such as this winter.

The record of SSW events goes back to the 1950s with the introduction of radiosonde balloons which are used to take observations high in the stratosphere on a routine basis. Since then, there has been typically one SSW every two extended winters. However, there are occasional runs of years with no warming events at all e.g. in the 1990s. There are also winters with two warmings such as the winter of 2009/10.

Professor Adam Scaife, Head of Long-Range Forecasting at the Met Office, said: “Although we have not seen it before, we recently documented the chances of an unprecedented three SSW events happening in one winter. Our research work, using multiple computer simulations, showed that this could occur about once in every 250 winters.”

Professor Scaife added, “Although this is very rare, we also found that the chance of multiple SSW events is increased during El Niño and so the chance of multiple events this winter is raised.”

3rd SSW winter

Forecast pressure for mid-March showing relatively high pressure over Iceland and low pressure over mid latitudes (Units: hPa).

A SSW is a disruption of the normal westerly air flow 10 to 50 km above the earth. This often makes the jet stream meander more, which can lead to the development of a large area of high pressure over northern Europe at the Earth’s surface. This can ‘block’ the Atlantic low-pressure systems which are responsible for the relatively mild, wet and windy weather that often occurs in UK winters. This blocking pattern increases the chance of cold, dry weather in the UK and mild, wet and windy conditions for southern Europe. However, the impacts of an SSW do not always equate to cold weather, for example, we have only seen intermittent drops in temperature around the two SSW events early this winter and typically around 70% of events are associated with a cold snap.

SSW is just one of a number of global drivers that can affect weather in the UK, the current SSW is consistent with the latest long-range outlook for March which suggests a continued increased chance of blocked, high-pressure conditions to the north of the UK and a southward shift in the Atlantic jet stream.



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Building resilience: climate solutions for a changing world

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1 week ago

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May 9, 2024

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In an era defined by environmental uncertainty, the need to fortify our communities against the impacts of climate change has never been more pressing. Climate resilience – a term often heard in discussions surrounding climate action – refers to humanity’s capacity to adapt and withstand the adverse effects of climate change while maintaining essential functions and minimizing disruption to livelihoods and ecosystems.

But what exactly are climate resilience and climate solutions?

Understanding Climate Resilience: Climate resilience encompasses a spectrum of strategies aimed at softening the risks posed by climate change. It involves building robust infrastructure, implementing sustainable land-use practices, fostering community preparedness, and enhancing ecosystem resilience. Essentially, it’s about future-proofing societies and environments against the challenges of a changing climate.

Defining Climate Solutions: Climate solutions refer to the various interventions, technologies, and policies designed to address climate change and enhance resilience. These solutions span a wide range of sectors, from renewable energy and sustainable agriculture to disaster risk reduction and climate-smart infrastructure. By adopting and scaling up these solutions, society can partially adapt to climate impacts, and build a more sustainable future.

Case Studies: Met Office’s Climate Resilience Initiatives:

  1. Climate Services for Developing Nations: The Met Office, in collaboration with international partners, provides climate services to developing nations to enhance their resilience to climate change. These services include tailored climate information, early warning systems for extreme weather events, and capacity-building initiatives to empower local communities to manage climate risks effectively. By equipping vulnerable regions with the tools and knowledge needed to anticipate and respond to climate impacts, the Met Office is helping build resilience on a global scale.
  2. Climate Change Adaptation in Urban Environments: With rapid urbanisation and population growth, cities face unique challenges in the face of climate change. The Met Office is involved in research and development projects aimed at enhancing climate resilience in urban environments. This includes modelling future climate scenarios, assessing climate risks to infrastructure and communities, and developing adaptation strategies to bolster resilience. By integrating climate considerations into urban planning and infrastructure development, cities can better withstand the impacts of extreme weather events and changing climate patterns.
  3. Enhancing Agricultural Resilience: Agriculture is particularly vulnerable to the impacts of climate change, with shifting weather patterns, extreme temperatures, and fluctuations in rainfall posing significant challenges to food security and livelihoods. The Met Office collaborates with agricultural stakeholders to consider climate-smart farming practices, improve crop forecasting capabilities, and provide climate information to farmers. By promoting sustainable agriculture and supporting adaptive measures, the Met Office is helping farmers build resilience to climate variability and ensure food security for future generations.

In conclusion, ‘resilience’ is not just a buzzword; it’s critical for safeguarding our planet and securing a sustainable future for all. By embracing climate solutions and investing in resilience-building initiatives, we can navigate the challenges of a changing climate and create a more resilient, equitable, and prosperous world for generations to come.



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A wet and dull April

Published

3 weeks ago

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May 1, 2024

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It will be no surprise for many to hear that April 2024 has been a wet month. In what has felt like an unsettled spring so far, the UK has had its sixth wettest April since the series began in 1836, according to provisional statistics from the Met Office.  

Sunshine has been in short supply, with the UK provisionally recording just 79% of its long-term average for the month.

Wetter than average

The UK experienced 55% more rainfall than an average April, with 111.4mm falling across the month, making it the sixth wettest April in the series and the wettest April since 2012.

Many areas recorded more than their long-term average monthly rainfall, with Scotland experiencing its fourth wettest April in a series which started in 1836. It saw 148.9mm of rainfall across the month – more than 60% of its average and the wettest April since 1947.

Some places in Scotland saw more than double their average rainfall for the month. Edinburgh in particular saw very large rainfall totals, receiving 239% of its average April rainfall, which is its second wettest on record, falling only behind totals in 2000. East and West Lothian, Aberdeen, Clackmannan, Berwickshire and Cumbria, among others, also recorded more than double their average rainfall in the month. A rain-gauge at Honister Pass in the English Lake District recorded more than 400mm of rain.

Met Office Scientist Emily Carlisle said: “April has been a continuation of the past few months: often wet, windy and unsettled. April showers were present from the beginning of the month, with frontal systems bringing persistent precipitation across the UK. Although a high-pressure system moved over the UK on the 20th bringing some drier weather, by the end of the month, low pressure was back in charge, bringing with it more rain.”

Temperatures around average

April was a month of two halves when it comes to temperatures. The month started off warm, particularly along the southeast coast of England. Writtle in Essex recorded 21.8°C, making it the hottest day of 2024 so far in the UK.

Temperatures then dropped, remaining slightly below average for most of the last two weeks of April. This balanced out the warmer temperatures at the start of the month and resulted in a provisional average mean temperature of 8.3°C for the UK, only 0.4°C higher above the 1991-2020 long-term average.

Cloudy conditions often resulted in overnight temperatures being held up, with the average minimum temperature being above average (+0.8°C).

A dull month

Along with being a wet month, April has also been a dull month. The UK provisionally recorded 79% of the long-term average sunshine duration, with 122.9 hours.

One named storm

April saw Storm Kathleen arrive on the 6th, bringing heavy rain to Scotland, Wales, parts of Northern Ireland and the west coast of England. Kathleen also brought strong winds across the UK, with gales along coasts, particularly in the north and west of the UK. Kathleen was the eleventh named storm of the 2023/24 season. This is only the second time that the Met Office has reached the letter K since they began naming storms in 2015.

Spring so far…

Meteorological spring (March to May) so far has been wet. Both England and Wales have already seen more than their long-term average rainfall for the entirety of the season, while the UK has seen 96%. At this point in the season, we’d expect to see 66% of average.

Provisional April 2024 Mean temp (°C) Sunshine (hours) Rainfall (mm)
Actual  Diff from avg (°C) Actual % of avg Actual % of avg
UK  8.3 0.4   122.9 79  111.4 155
England  9.3 0.6   127.0 78 85.5 152
Wales  8.5 0.4  113.3 72 135.8 154
Scotland  6.6 0.0  119.2 84 148.9 160
N Ireland  8.3 0.3  118.4 80 104.6 141



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Antarctic sea ice in 2023

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1 month ago

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April 17, 2024

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Each year, from June-October, polar climate scientists from the Met Office produce a series of monthly sea ice briefings for the government and the general public. These briefings describe the state of Arctic and Antarctic sea ice, compare how these relate to historic patterns, and, where possible, assess causes of unusual behaviour.

Sea ice is frozen seawater that floats on the surface of the ocean and is found when temperatures are cold enough for sea water to freeze. The extent of sea ice is a key climate indicator, because sea ice cover insulates the ocean in winter and reflects sunlight in summer, as well as providing a habitat for a range of species. 

A view of Antarctica showing patches of sea ice, ice bergs and the Antarctic continent's mountains in the distance.

Here, Senior Scientist Alex West talks about the 2023 Antarctic sea ice minimum and its interaction with the ocean and atmosphere.

Lowest sea ice extent on record

Antarctic average sea ice extent for 2023 was the lowest on record. During the ice growth season from June-October, ice extent was exceptionally low for the time of year, reaching over 1 million square km below previous record lows and setting a new record low maximum extent by a very large margin. For much of the rest of the year, the ice was at record or near-record low levels, recording a second successive record low minimum in February (Figure 1).

The annual cycle of Antarctic sea ice build up and loss with individual years highlighted. 2023 was a record low year for Antarctic sea ice extent.

Figure 1. Antarctic sea ice extent in 2023 (bold black line) with other recent years indicated, as well as earlier years with notably low sea ice extent. The 1981-2010 average is also shown, with the shaded region indicating 2 standard deviation intervals.

The very low extent from June-October was partly caused by enhanced warm northerly winds, associated with persistent areas of high and low pressure (Ionita, 2024). Early in the ice growth season, from May-July, these were concentrated near the Antarctic Peninsula, in the Weddell and Bellingshausen Sea regions; later in the growth season, from August-October, the strongest winds were to be found further west, in the Ross Sea. The position of the lowest sea ice conditions changed similarly.

However, it is likely that the ocean also played a part. The low extent of 2023 continues a pattern of very high variability in Antarctic sea ice since 2007, with first high and then low sea ice conditions persisting for long periods of time, in a way unlikely to be caused by known atmospheric changes (Hobbs et al., 2024). A key moment in this period of high variability was a large reduction that occurred in 2016, and this is thought to be linked to changes in the upper ocean caused by stronger westerly winds mixing warmer waters below towards the surface (Earys et al., 2021; Zhang et al., 2022). Further mixing of warm waters cannot be ruled out as an additional cause of the very low extent of 2023.

The precise contribution of anthropogenic (human-caused) global warming to the record low sea ice of 2023 is not yet known. While climate models predict that Antarctic sea ice extent will decrease in response to anthropogenic warming, variability in the past 15 years has been considerable, with very high extent from 2012-2014 followed by the current period of very low extent (Figure 2). Further extreme variability in either direction remains possible in the years ahead.

The monthly extent of Antarctic sea ice from 1979 compared with the average from 1981-2010. This view makes it easier to see long-term changes in sea ice.

Figure 2. Antarctic sea ice monthly anomalies over the period of satellite observations. For each month, the 1981-2010 average ice extent for that month is subtracted. This largely removes the seasonal cycle so that subtler long-term changes can be viewed more easily.

During April we are exploring the topic of the ocean and climate. Follow the #GetClimateReady hashtag on X (formerly Twitter) to learn more throughout the month.

References

Eayrs, C., X. Li, M.N. Raphael and D.M. Holland (2021) Rapid decline in Antarctic sea ice in recent years hints at future change. Nat. Geosci., 14, 460–464. https://doi.org/10.1038/s41561-021-00768-3

Hobbs, W., and Coauthors (2024): Observational Evidence for a Regime Shift in Summer Antarctic Sea Ice. J. Climate, 37, 2263–2275, https://doi.org/10.1175/JCLI-D-23-0479.1

Ionita M (2024) Large-scale drivers of the exceptionally low winter Antarctic sea ice extent in 2023. Front. Earth Sci. 12:1333706, https://doi.org/10.3389/feart.2024.1333706

Zhang, L., T.L. Delworth, X. Yang, F. Zeng, F. Lu, Y. Morioka and M. Bushuk (2022) The relative role of the subsurface Southern Ocean in driving negative Antarctic Sea ice extent anomalies in 2016–2021. Commun. Earth Environ., 3, 302. https://doi.org/10.1038/s43247-022-00624-1

Antarctica map showing Antarctic Peninsula

A map of Antarctica showing the Antarctic Peninsula separated by the Bellingshausen and Weddell Seas. Map: Adobe Stock.



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