December on track to be the mildest on record

24 12 2015

Mowing the lawn has been the reality for some so far this December, with unseasonably high temperatures. It looks as though the UK is on track to break the record for the warmest December since records began in 1910 and some areas have also seen their wettest.

The latest temperatures for December (1st to 22nd) reveal that the month so far has been far warmer than normal. Early provisional figures* reveal that the mean temperature for December in the UK has so far has been 8.1C, which is 4.2C above the long-term average for the month and well above the previous record of 6.9C set in 1934.

The December figure for England has so far been 9.5C, that’s 5.1C above the same long-term average and 2C above the record of 7.5C set in 1934, and the other UK nations have been similarly warm:

  • the mean temperature of 9.3C in Wales, higher than the previous post-1910 record of 7.5C set in 1934, and 4.8C above average
  • the mean temperature of 5.6°C in Scotland is 2.8C above average, but is so far slightly lower than the previous December record of 5.8C set in 1988
  • the mean temperature of 7.5°C in Northern Ireland is 3C higher than average, and marginally higher than the 1988 December record

Tim Legg of the Met Office National Climate Information Centre said: “With no sign of any significantly cold weather to come in the remaining 9 days of the month, we’re on track to break the warmest December record which was set back in 1934.”

Rainfall 1 - 22 Dec 2015

Rainfall 1 – 22 Dec 2015

MeanTemperature Dec 1 - 22, 2015

MeanTemperature Dec 1 – 22, 2015

 

 

 

 

 

 

 

 

 

 

Rainfall and sunshine figures so far confirm December has been dull and wet across most of the UK, with sunshine well down on the long-term average while precipitation (which of course has fallen mainly as rain) has been well above.  Some places have seen record breaking rainfall:

  • Cumberland 310.9mm rainfall 1 – 22nd Dec (previous record 248.2mm 2006),
  • Westmorland 474.4mm 1 – 22nd Dec (previous record 365.1mm 2006)
  • Dumfriesshire 314mm rainfall 1 – 22nd Dec (previous record 307.5mm 2013)
  • Carnarvonshire 441.3mm rainfall 1 – 22nd Dec (previous record 376.6mm 1965)
  • Roxburghshire 237.8mm rainfall 1 – 22nd Dec (previous record 219.7mm 2013)

 

EARLY mean temperature sunshine duration precipitation
1-22 Dec 2015 Act Anom Act Anom   Act Anom
  Deg C Deg C hours % mm %
UK 8.1 4.2 17.7 43 148.0 123
England 9.5 5.1 19.8 42 86.5 99
Wales 9.3 4.8 16.3 39 237.1 143
Scotland 5.6 2.8 14.1 46 229.1 140
N Ireland 7.5 3.0 20.7 56 130.4 114

 

You can find out what the rest of the year has been like on our climate pages.

*Data from the Met Office’s UK digitised records dating back to 1910.

Please note that these provisional figures, especially for rainfall and sunshine, are subject to revision. Anomalies are expressed relative to the 1981-2010 averaging period.





The science questions following a global deal on climate

15 12 2015

There has been a huge amount of worldwide media coverage following the weekend’s announcement of a globally agreed deal to try to limit global warming to 2 °C or less. Here Professor Stephen Belcher, the Director of the Met Office’s Hadley Centre for Climate Science and Services, discusses some of the scientific questions raised by the agreement.

At the heart of the Paris agreement is the aim to hold “the increase in the global average temperature to well below 2 °C above pre-industrial levels”*. Why 2 °C? Because global governments have previously agreed this is an achievable target which could reduce some of the most dangerous impacts of climate change – such as melting of ice in places like the Greenland which would cause large scale sea level rise.

The agreement went even further, however, by saying efforts should be pursued to “limit the temperature increase to 1.5 °C”. This is a more ambitious target, especially given news from the Met Office in November that the world has reached the 1 °C above pre-industrial marker for the first time this year.

It raises some interesting questions for scientists as to how we can achieve this: how much do we need to cut global greenhouse gas emissions? How quickly do we need to make those cuts? What else might we need to do to be able to keep warming to 1.5 °C – for example, would we need to develop technologies that actually remove CO2 from the atmosphere? If temperatures overshot 1.5 °C and then reduced to 1.5 °C, would sea level also overshoot and then reduce?

To answer these questions more precisely will require scientists to get an even more detailed understanding of how sensitive our climate is to CO2 and other greenhouse gases.

Key to this will be improving understanding of what we call ‘Earth system feedbacks’. These are natural feedback processes which could either increase or decrease the amount of warming we might expect in response to a given amount of greenhouse gases. For example, we know that there are stores of greenhouse gases ‘locked away’ under frozen ground (permafrost) in some parts of the world, such as northern  Russia. If that permafrost melts due to climate change, the gases would be released – which could further increase warming.

Scientists around the world are already working on providing answers to these questions by developing a new breed of ‘Earth System Models’ (essentially complex simulations of our planet run on powerful supercomputers), which take more of these feedback processes into account, and so will help inform planning of emissions to achieve the warming targets agreed in Paris.

Whether we limit warming to 2 °C or 1.5 °C, it’s clear we can expect some further change to our global climate over the coming decades. Research shows us that this will lead to some impacts and it’s vital that we understand in more detail what this means at a regional and local level.

For example, research tells us that some parts of the world can expect more extreme weather – including heat waves and increases in extreme rainfall. For those planning everything from future homes, to flood defences, to vital infrastructure, the detail on what to expect is essential.

Again, these are questions which science is already working to answer by harnessing new research and ever more powerful supercomputing technology. At the Met Office, we’ve published papers showing that we can expect more intense summer downpours for the UK in future – which raises the risk of flash flooding. We’ve also shown how the chances of summer heatwaves in Europe have dramatically increased.

There’s still much more work to do in this area and it will be vital that the information generated by this research is presented in a way that allows everyone to make informed decisions about how we can become more resilient to our climate – whatever changes we can expect.

*There’s a lot of scientific debate about exactly what ‘pre-industrial levels’ means and how you would measure that, but here we use the average of temperatures during the period 1850-1899 as our representation.





Did climate change have an impact on Storm Desmond?

7 12 2015

The exceptional rainfall in Cumbria over the past few days saw the fall of numerous records and has led many to ask whether it is linked to climate change. The records are based on digitised data going back to the 19th Century.

A gauge at Honister Pass recorded 341.4mm of rainfall in the 24-hours up to 1800 GMT on 5 December 2015, making for a new UK record for any 24-hour period. This beat the previous record of 316.4mm set in November 2009 at Seathwaite, also in Cumbria. A new 48-hour record (from 0900 to 0900 hrs) was also set, when 405mm was recorded at Thirlmere in Cumbria in just 38 hrs.

The weekend’s record rainfall was associated with a persistent, south-westerly flow bringing a ‘river of moisture’ from as far away as the Caribbean and the Gulf of Mexico. Ocean temperatures in the West Atlantic are currently well above normal and may well have contributed to the very high levels of moisture in the air masses which unleashed rainfall on the Cumbrian fells.

Professor Dame Julia Slingo, Met Office Chief Scientist, says “It’s too early to say definitively whether climate change has made a contribution to the exceptional rainfall. We anticipated a wet, stormy start to winter in our three-month outlooks, associated with the strong El Niño and other factors.

“However, just as with the stormy winter of two years ago, all the evidence from fundamental physics, and our understanding of our weather systems, suggests there may be a link between climate change and record-breaking winter rainfall. Last month, we published a paper showing that for the same weather pattern, an extended period of extreme UK winter rainfall is now seven times more likely than in a world without human emissions of greenhouse gases.”





2015 likely to be the warmest on record

25 11 2015

This year’s global average surface temperature is likely to be the warmest on record according to data from the Met Office, and is expected to continue the trend showing 15 of the top 16 warmest years have happened since 2001.

These findings concur with the World Meteorological Organisation (WMO) findings also announced today.

2015 a more ‘clear-cut’ record

Provisional figures up to the end of October show this year’s near-surface global temperature as estimated from the HadCRUT dataset has been around 0.71 ±0.1 °C above the 1961-1990 average of 14.0 °C.

This is in-line with the Met Office’s forecast, issued in December 2014, which predicted 2015 global temperatures would be between 0.52 °C and 0.76 °C* above the 1961-1990 average, with a central estimate of 0.64 °C.

In HadCRUT, this year is clearly warmer than 2014, the previous nominal warmest year in the record, which was 0.57 ±0.1 °C above the 1961-1990 average.

Global Temperature graph

Colin Morice, a climate monitoring scientist at the Met Office, said: “Last year was nominally the warmest year in our records but wasn’t much higher than the other top warmest years. This year the temperature is markedly warmer than anything we’ve previously seen in the 166-year record, meaning its position at the top of the rankings looks set to be much more clear cut.”

 

The HadCRUT dataset, jointly compiled by the Met Office and Climatic Research Unit at the University of East Anglia, uses data from more than 6, 000 observation sites around the world and observations from ships and buoys at sea. It is recognised as one of the world’s leading indices of global temperature.

Temperatures 1 °C above ‘pre-industrial’ for first time

2015 is set to mark the first time in the record that annual global temperatures reach 1 °C above ‘pre-industrial’ temperatures (taken here as an average of the 1850-1900 period*).

This is important because governments around the world have agreed the aim of trying to limit warming to 2 °C or less above pre-industrial to try to avoid the most dangerous impacts of climate change.

Leading independently-run datasets agree

Findings from HadCRUT are very similar to independently-run global temperature datasets compiled by the US National Oceanic and Atmospheric Administration and NASA Goddard Institute of Space Studies.

Information from all three datasets is included in an announcement from the World Meteorological Organization (WMO) on global temperature, which also concludes this year is likely to be the warmest on record.

Where did 2015’s warmth come from?

This year has seen a strong El Niño develop, with unusually warm sea surface temperatures across the Tropical Pacific, releasing heat into the atmosphere and pushing up global temperatures.

Global Temperature chart

Global Temperature chart

While this has contributed to 2015’s warmth, this is likely to be comparatively small compared to the long-term influence of warming caused by human greenhouse gas emissions.

This is backed up by research from the Met Office last year which showed global temperatures seen in recent years would be highly unlikely in a world without human influence on the climate.

What’s in store for the year ahead?

Last year saw record or near record warmth globally, this year is warmer still and the current expectation is that next year will also be warm.

This is due to two factors: firstly, the ongoing warming due to human influence, and secondly although the current El Niño is expected to peak around the end of this year, its main warming influence is usually felt in the months afterwards. For example, a strong El Niño peaked at the end of 1997 – but it was 1998 which went on to become a record (at the time) by some margin.

There are other natural factors – such as changes in longer term ocean cycles or volcanic eruptions – which could act to reduce global temperatures next year, so there will always be some uncertainty.

The Met Office will give more detail in the expected global temperature for 2016 when it publishes its forecast in the latter part of December.

 

* While late 19th century temperatures are commonly taken to be indicative of pre-industrial, there is no fixed period that is used as standard and a variety of other periods have been used for observational and palaeo datasets. There are limitations in available data in the early instrumental record, making the average temperature in the reference period less certain. There is not a reliable indicator of global temperatures back to 1750, which is the era widely assumed to represent pre-industrial conditions. Therefore 1850-1900 is chosen here as the most reliable reference period, which also corresponds to the period chosen by IPCC to represent a suitable earlier reference period.





How much does the weather influence what we put in our grocery basket?

14 10 2015

What do you think determines what we buy when we go food shopping? Whilst the odd item may catch our eye and lead to one of those ‘impulse purchases’, British consumers can in some ways be rather predictable when it comes to what influences their choices.

For example, when Christmas comes around, it isn’t hard to predict that we’re going to be looking for turkey and sprouts. And when the economy is doing well, the chances are we’ll be buying a few more bottles of expensive wine.

But one of the most important factors – in fact one which around half of the decision makers at UK retailers and suppliers would count in their top three – is the weather. And whilst Santa’s sleigh may come to town once a year like clockwork, us Brits – more so than most – know that the weather doesn’t quite work in such a predictable manner.

Capture

The weather can have a significant impact on what we choose to buy when in store, and ultimately on retailer performance. For example, a four degree increase in temperature can lead to sales of burgers increasing by nearly half, according to one leading supermarket.

When the weather changes, retailers risk losing millions through low stock levels, empty shelves and disappointed customers. It can lead to unexpected fluctuations in store footfall and sales, shortages in availability, and impact the costs and efficiencies of the whole supply chain – this is particularly true for fresh, chilled and seasonal products.

We wanted to understand a bit more about how the UK grocery sector as a whole accounts for the weather in its planning, so we have developed a new report based on opinions of key executives and managers across over 200 food suppliers and retailers in the UK. The report looks at just how much the weather impacts their business – and how they use weather products to make those all-important stock predictions. After all, no one likes going to the supermarket to find that their favourite food item is sold out.





What do we know about the coming winter?

15 09 2015

There has been some speculation in the media today that we may be in for a long, bitterly cold winter because an El Niño is under way in the tropical Pacific.  However it is still far too early to speculate about what sort of winter the UK will have.

During an El Niño sea surface temperature in the east Pacific warms, altering weather patterns around the globe.  The influence of an El Niño over the UK and western Europe tends to be weaker and less predictable than elsewhere because of how far away we are from the event itself.  There is a link in late winter, when we can see a slightly higher risk of a colder than usual end to winter in El Niño years.

This map shows the effect El Nino has on temperatures around the globe.

This map shows the effect El Nino has on temperatures around the globe.

 

That’s not where it ends when looking at the UK winter, though. Other factors also have an influence, such as sea surface temperature in the North Atlantic, the Sun’s output, and changes in winds high in the atmosphere above the Equator known as the Quasi-Biennial Oscillation. These could wipe out the influence from El Niño, and all of them need to be taken into account to predict the winter.

Scientist and Manager of Met Office Predictability Research, Dr Doug Smith, said: “We continue to make improvements in the developing area of long-range forecasting but with all the competing influences in the climate it remains too early to predict the coming winter with much confidence.”

Our 30-day forecasts remain the best way for the public to get a long-range look at the weather we’ll see, while our detailed 5-day forecasts and warnings will keep everyone up-to-date for any periods of severe weather.

 





So what happened to our summer?

28 08 2015

Our Chief Scientist Professor Dame Julia Slingo OBE FRS reflects on this summer’s weather and what has influenced it:

No-one can deny that we have had a pretty disappointing summer with a lot of unsettled weather and only a few warm spells, especially through July and August. Our weather has been dominated by low pressure over and to the west of the country that has brought us periods of heavy rain from the south – what we call the Spanish Plume. So what has been happening?

If we look beyond our shores there have been some big changes in the global climate this year. El Niño is in full flight, disturbing weather patterns around the world. The low pressure that has dominated our weather is part of a pattern of waves in the jet stream around the world that has brought crippling heat waves to places like Poland and Japan. And, looking back over past El Niños, you could have expected that a more unsettled summer might be on the cards for the UK. Closer to home the North Atlantic is more than 2 degrees colder than normal. It seems quite likely that the unusually cold North Atlantic has strengthened and pushed our jet stream south, also contributing to the low pressure systems that have dominated our weather.

So could all this have been anticipated? Seasonal forecasts for this summer suggested that temperatures and rainfall would be near normal. However, as the season progressed all the leading models around the world failed to capture the signal for unsettled weather over the UK. We all know that forecasting months and seasons ahead is still in its infancy and much more research needs to be done. On the other hand our day-to-day forecasts have been really successful in allowing us to warn of bad weather, highlighting yet again the benefits of our research that has delivered year-on-year and decade-by-decade improvements in forecasting skill. Our 5-day forecast is now as accurate as our 1-day forecast was when I started my career. This enables us to make so many decisions that keep us safe, protect our property, keep our infrastructure running and even when to go out and enjoy the sunshine!

All of this cannot happen without improvements to research and technology, and this week the first phase of our new supercomputer went live, five weeks ahead of schedule. This will enable us to provide even more accurate and relevant weather and climate forecasts to all of us, our government, emergency responders, and our many other customers at home and abroad.

The news that the BBC has decided that the Met Office won’t be their main weather provider when the current contract ends has raised the question of where will the new provider get their information from. It’s important to understand that no weather forecasting organization, whether it is a National Met Service like the Met Office or an independent company, can provide a service without a forecast, and that it is the leading meteorological agencies, like the Met Office, that build and deliver those forecasts. So whoever the BBC chooses to deliver their weather services in future, you can be sure that Met Office observations and forecasts will continue to be at the heart of them. We are committed to driving forward the skill and usefulness of our forecasts and ensuring that all of us benefit from the advances the Met Office makes in the coming years with our new supercomputer.





Met Office in the Media – 7 August 2015

7 08 2015

Earth from space

An article published today makes a number of claims about Met Office weather and climate science.

It would be difficult to cover all the points raised in this blog, but here we look at the science and facts behind a few of the assertions.

The first decadal forecast issued in 2007

We did indeed publish the first groundbreaking decadal forecast in 2007. It had two headline statements:

  1. that half of all years after 2009 would be warmer globally than the record year at that time (1998) – This is doing well so far with two out of five years (2010 and 2014) warmer than 1998 and given current temperature levels, it’s likely this will be 3 out of 6 by the end of this year, consistent with our forecast for 2015
  2. that 2014 would be 0.3 °C ± 0.21 °C warmer than 2004 (giving a range of 0.09 °C to 0.51 °C) – WMO figures show the global temperature for 2014 was 0.13 °C higher than that in 2004; which is within the range of the forecast

Adjustments to global temperature data

The article says we adjust our temperature figures ‘without justifying why it is scientifically appropriate’. In fact, numerous peer-reviewed science papers from research centres across the world provide detailed explanations of how and why datasets are adjusted to ensure they are as accurate as possible. This is available for anyone to view and analyse.

The conclusion that the world has warmed is supported by independent analysis of global temperature data.

European heatwaves

We published a paper stating heatwaves like that seen across Europe in 2003 would become more frequent under climate change. Subsequent observations back up these conclusions; 2006 saw comparable heat in the UK, 2010 saw intense heat across eastern Europe, and there’s been a prolonged heatwave across much of Europe this year (although not in the UK).

Weather extremes

Met Office research supports climate research centres around the world which concludes we expect more extremes of heat and rainfall as the world continues to warm. The article says this ‘simply hasn’t happened’ but in fact, research shows there has been an increase in both. While here in the UK, we have also seen an increase in the number of temperature and rainfall records.

The article also states ‘the Met Office did all it could to claim the rain that caused last year’s exceptional flooding… was the worst ever recorded.’ We’ve done studies (here and here) of the exceptional rainfall in winter 2013/14., which across southern England was one of the, if not the most, exceptional periods for winter rainfall in around 250 years. Here’s a fuller research piece about the winter 2013/14 storms.

Greenland ice

The article says that we claimed Greenland ice would melt in future due to global warming. We did, and we were clear that it would take thousands of years to happen, not ‘any time soon’. Observations show Greenland has been losing 300 gigatonnes (1 gigatonne is 1000,000,000 tonnes) of ice a year over the last 12 years and research shows surface temperatures have clearly risen.

Other claims

A series of other claims are made in the article, mostly focusing on our forecasts over seasonal to decadal timescales. The Met Office is at the forefront of this pioneering area of research and we are increasing skill in this area.

According to standards set by the World Meteorological Organization the Met Office is ranked as the most accurate global met service in the world. We will continue our research in collaboration with our global scientific partners to improve this vital area of science.





Record hot to record cold in a July of extremes

3 08 2015

While this year’s July may not have broken any monthly records – it was book-ended with some localised daily records at both extremes of the temperature spectrum.

The month started with the highest recorded July temperature in our UK climate records with 36.7C recorded at Heathrow on 1 July.

Then on the last day of the month, we saw the opposite extreme – with a number of stations across the UK breaking their lowest recorded July temperature.

Some of these stations have fairly long records – below we’ve highlighted those stations which broke their July low record which have observations going back for 30 years or more.

STATION COUNTY PREVIOUS RECORD PREVIOUS RECORD DATE YEARS OF DATA TEMP 31/07/15
ALICE HOLT LODGE Surrey 3.9 03/07/1984 64 3.5
KEELE Staffordshire 5.2 16/07/2001 63 5
EXETER AIRPORT Devon 3.3 01/07/2011 50 2
CHIVENOR Devon 5.7 07/07/1996 38 5.6
PERSHORE Worcestershire 3 04/07/1965 36 2.7

These temperatures came about after several days of a northerly airflow which brought colder than average air over the UK. Clear skies allowed temperatures to drop rapidly overnight across many spots, leading to some of the localised records.

None of these new station records came close to breaking the all-time UK record for July of -2.5C which was set at both St Harmon (Powys) on 9 July 1986 and Lagganlia (Inverness-shire) on 15 July 1977. It’s worth noting here that lowest daily temperature records exclude stations above 500 metres above mean sea-level.

Other extremes for July 2015 are:

  • The wettest day was recorded at Cambridge Botanic Garden on the 16th, with 87.1mm of rain recorded in 24 hours. This is significantly more than the whole-month average for July at that station, which is 50.7mm.
  • The strongest gust was recorded at the Needles on the Isle of Wight on the 26th, with 60mph.
  • The Sunniest day was on Fair Isle, Shetland, on the 26th, with 16 hours of sunshine recorded.
  • The coldest temperature recorded during the month was a chilly -0.6C at Katesbridge in Down, Northern Ireland on 15 July – although this wasn’t a record for that station.
  • The warmest temperature was 36.7C recorded at Heathrow on 1 July – you can read more about that on our blog.




Early July sees big rainfall contrasts

20 07 2015

After a hot and humid start to the month, when record daily maximum temperatures were recorded at several stations across the country on 1 July, it has been a fairly average month so far for the UK as a whole. However, on a regional scale there are some contrasts.

Using figures up to 15 July, mean temperatures have been close to or above average, with counties in eastern and southeastern England highest relative to average.

Meanwhile, for rainfall there are more notable variations, with eastern parts of England having received around or less than half the amount of rainfall that would be expected by mid-month. For example, Surrey and Sussex have both recorded less than 20% of the month’s average rainfall with 7.8mm and 9.9mm respectively. By the 15th of the month you would normally expect around 48% of the whole-month average.

This is in comparison with parts of Eastern Scotland where some places have already recorded more rainfall than the whole-July average. Aberdeenshire and Kincardineshire have already seen rainfall in excess of July’s average at 79mm and 106.6mm.

After the hot, sunny start to the month there have been periods of unsettled weather, with weather systems arriving from the Atlantic bringing rain or showers at times. This has been interspersed with drier, sunny spells.

With west or southwesterly winds dominating, there have been some rather cloudy days in the south, leading to mild nights.

The table below shows figures for the 1-15 July. You would normally expect about 48% of the full-month average for sunshine and rainfall at this point in the month.

Mean temperature Sunshine duration Rainfall
1-15 July
Act (°C) Diff from avg (°C) Act (hrs) % of avg Act (mm) % of avg
UK 15.5 0.4 88.0 51 46.9 60
England 17.0 0.7 103.7 54 30.5 49
Wales 15.4 0.2 89.2 50 56.4 61
Scotland 13.3 0.0 66.8 47 71.9 72
N Ireland 14.2 -0.4 57.7 41 45.9 57

 








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